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					Chemrock Highlight 1999


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Date:         Tue, 16 Feb 1999 18:37:44 -0500
Reply-To:     Chemical Propulsion Research <CHEMROC@UGA.CC.UGA.EDU>
Sender:       Chemical Propulsion Research <CHEMROC@UGA.CC.UGA.EDU>
From:         "James E. Lanier" <jelanier@BELLSOUTH.NET>
Subject:      Ammonium Perchlorate Synthesis
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    I called a manufacturer of AP to satisfy my curiosity about questions I
had. For one thing, they use PbO2 anodes but are looking at the feasibility
of using platinum. Why?..Because they replace anodes several times daily!
    They use ammonium chloride in an electrolytic bath to precipitate the AP
(from sodium perchlorate). I asked if they used an additive to help remove
the chlorate ion and they said they did not. One thing I didn't ask was if
they were using ceramic substrates for the PbO2 anodes. Maybe next time I
will remember.

Jim

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Date:         Tue, 16 Feb 1999 21:18:57 -0500
Reply-To:     weaver_r@mediasoft.net
Sender:       Chemical Propulsion Research <CHEMROC@UGA.CC.UGA.EDU>
From:         Rich Weaver <weaver_r@MEDIASOFT.NET>
Organization: At home in the mountains
Subject:      Re: Ammonium Perchlorate Synthesis
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"James E. Lanier" wrote:
>
>     I called a manufacturer of AP to satisfy my curiosity about questions I
> had. For one thing, they use PbO2 anodes but are looking at the feasibility
> of using platinum. Why?..Because they replace anodes several times daily!

I find this quite strange. They must be using one hellofa current density. Some
of the articles I've read state run lives of 2000 - 9000 hours for PbO2 anodes.

>     They use ammonium chloride in an electrolytic bath to precipitate the AP
> (from sodium perchlorate). I asked if they used an additive to help remove
> the chlorate ion and they said they did not. One thing I didn't ask was if

So what do they do with the waste? Do the recycle it or dump it? If they recycle
it, that pesky ammonia could cause some problems.

> they were using ceramic substrates for the PbO2 anodes. Maybe next time I
> will remember.
>

I would like to hear that answer and I would like to know who/where they buy
them or if they make them. Some PbO2 anodes have no substrate, others graphite,
titanium, tantalum etc.

Rich

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Date:         Wed, 17 Feb 1999 17:52:46 -0500
Reply-To:     Chemical Propulsion Research <CHEMROC@UGA.CC.UGA.EDU>
Sender:       Chemical Propulsion Research <CHEMROC@UGA.CC.UGA.EDU>
From:         "James E. Lanier" <jelanier@BELLSOUTH.NET>
Subject:      Welcome to a new member of Chemroc
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As a number of us have expressed an interest in perchlorate synthesis, I
thought it would be nice to have a chemroc member from the professional
ranks. I asked such a person to join and he is now a chemroc member. Let's
welcome Kent Richman who manages AMPAC (in ammonium perchlorate manufacture)
laboratories. Kent also worked with Thiokol as a propellant development
chemist. As chemroc list-manager I would like to personally welcome Kent to
the group.


James E. Lanier
chemroc list-manager
jelanier@uga.edu
jelanier@bellsouth.net


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Date:         Thu, 18 Feb 1999 00:31:22 +0100
Reply-To:     "Javier D." <javier.d@teleline.es>
Sender:       Chemical Propulsion Research <CHEMROC@UGA.CC.UGA.EDU>
From:         "Javier D." <javier.d@TELELINE.ES>
Subject:      Ammonium NItrate
Comments: To: arocket@nmt.edu
MIME-Version: 1.0
Content-Type: multipart/alternative;
              boundary="----=_NextPart_000_002C_01BE5AD6.02AC4CA0"

This is a multi-part message in MIME format.

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Hello everybody,

We work normaly with KNO3+sorbitol, We are studing a powerfull =
propellant, the common powerfull=20
propellant is AP+HTPB+Al but the temperature chamber is over 3.200=BA K =
and we can not obtain in=20
Spain a graphite rods with 50mm diameter to make nozzles or insertion =
nozzles. A good propellant=20
is the AP with AN over 50/50 + fuel.

Question.

Can we use the normal AN using only 35% AN in the mixture or with need =
use PSAN grade ?

We have stabilized the AN with Zinc oxide and water,   4kg AN with =
40liter water and 0.12 kg=20
Zinc Oxide, the problem is when the water are evaporated the AN is a big =
and hard crystal, we=20
need use a good anticake agent mix with the water to obtain AN powder.

Question.

What anticake agent we can use in our experiment ?=20


Thanks in advance,
Javier D.

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Date:         Wed, 17 Feb 1999 15:24:24 -0800
Reply-To:     Chemical Propulsion Research <CHEMROC@UGA.CC.UGA.EDU>
Sender:       Chemical Propulsion Research <CHEMROC@UGA.CC.UGA.EDU>
From:         Kent Richman <KRichman@APFC.COM>
Subject:      perchlorate production
MIME-Version: 1.0
Content-Type: text/plain

The way we make ammonium perchlorate is by electrolytically oxidizing a
sodium chloride solution to sodium chlorate, then, in a second step to
sodium perchlorate, which is reacted with ammonium chloride to produce
ammonium perchlorate (precipitated) and sodium chloride (solution). The
residual sodium chlorate present in the sodium perchlorate solution is
chemically treated before the final precipitation step.

=========================================================================
Date:         Sun, 21 Feb 1999 10:37:17 -0500
Reply-To:     Chemical Propulsion Research <CHEMROC@UGA.CC.UGA.EDU>
Sender:       Chemical Propulsion Research <CHEMROC@UGA.CC.UGA.EDU>
From:         "James E. Lanier" <jelanier@BELLSOUTH.NET>
Subject:      CHLORATES AND PERCHLORATES reprint
MIME-Version: 1.0
Content-Type: text/plain; charset="iso-8859-1"
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I chose to post this reprinted article for those interested in chlorate and
perchlorate synthesis. This may or may not be useful. (I see some flaws in
the article in my area of expertise). It will at least give us cause for
comment even if the procedures prove to be dated.


Jim



CHLORATES AND PERCHLORATES:
THEIR PRODUCTION

BY JAMES FINCKBONE

American Pyrotechnist Fireworks News
Volume 7, Number 6 June, 1974

The current drives by pressured bureaurocrats [sic] and safety
authorities to restrict the flow of chemicals with a potential for
abuse to the public, especially to hobbyists (e.g., the Child
Protection and Hazardous Substances Acts of 1966 and 1967),
have substantially achieved their goal, with most bulk-breakers
losing too much money to continue selling chemicals to such
customers. Because of this dwindling supply of certain chemicals,
particularly oxidizers, a few chemists among the deprived
hobbyists are considering a do-it-yourself approach, compounding
their own oxidizers from naturally occurring and relatively abundant
elements, not unlike the efforts during our Revolutionary War to
collect nitrates from every household's privy. But the most
important high-energy oxidizers for the pyrotechnist, the chlorates
and perchlorates, are not found in nature. Here we consider some
of the problems encountered by the hobbyist attempting to produce
these chemicals on a limited scale and with limited equipment. The
writer does not, however, claim the present article to be the final
word on the subject by a long shot, and readers are strongly urged
to forward their own observations and suggestions for printing in
future issues.
The two classes of agents in question did not become widely
available until the advent of the Industrial Revolution, although
they had previously been made by several European chemists by
heating red lead (Pb304) with mixes of prepared chlorine and a
base. Today the chloralkali industry produces chlorine and sodium
hydroxide in abundance, using an electrolytic process and ocean
brine. The chloride ion in the brine is converted to the chlorate ion
by the application of electrical energy (noted in the following
formulas as ''f", designating faradays, unit quantities of electricity),
and finally to the perchlorate ion. A metal donor added to the
solution causes a precipitate to form; e.g., barium carbonate will
precipitate out barium chlorate. The overall reaction is:

Cl - + 3(H20) + 6f -> Cl03-+ 3H2(gas)

Stepwise, the conversion is:

1 NaCl + H20 + 1f   -> NaOH + 1/2(H2) + 1/2(CI2) -1 -0*
2. 1/2(CI2) + H20   + 1f -> NaClO + 1/2(H2) 0-+1
3. NaClO + 2(H20)   + 2f -> NaCl03 + 2(H2) +1 -+5
4. NaCl03 + H20 +   1f -> NaCl04 + H2 +5 -+7

(*oxidation number of the chlorine)

There is an unstable intermediate between steps 2 and 3: the
chlorite ion, C102-.

Considering for the moment only the chemistry of the electrolytic
chlorate cell, free chlorine gas is initially formed at the anode (the
positively-charged electrode) as soon as current flows.
Simultaneously, at the negatively-charged cathode, hydrogen gas
and hydroxyl ions are forming. (Metallic sodium is also formed but
is unstable in water and reduces its hydrogen.) If the electrodes
are not separated by a diaphragm, the dissolved chlorine gas in
the electrolyte diffuses toward the hydroxyl ions and vice-versa,
forming the hypochlorite, hypochlorous acid (HCIO) and the
chloride ion (which is later oxidized). Since the oxidation voltage
for converting hypochlorite to chlorate is the same as for
conversion from chloride to hypochlorite, chlorate soon appears
(the oxygen being derived from the water, as confirmed by
tagged-isotope study), and more hydrogen gas is evolved from the
electrolyte. At the same time, the competing reaction of water
electrolysis is releasing oxygen gas at the anode and hydrogen at
the cathode, so the reaction efficiency is reduced to about 60 to 80
percent of theoretical. The final step, formation of the perchlorate
ion, occurs only when all chloride has been removed or reacted, as
its potential is of a higher value. The acidity (pH) of the solution will
influence other side-reactions, such as the evolution of chlorine
dioxide.

Industrially, chlorates and perchlorates are made in multi-cell
tanks of a corrosion-resistant steel alloy which serve as the
cathode, with dozens to hundreds of rod- or bar-shaped anodes
connected to a bus-bar and projecting vertically from the tank cover
into the electrolyte. Vents are provided to remove hydrogen and
other evolved gases and, along with the electrode connections,
deck the tank cover. Solutions are kept cool by means of a series
of steel pipes running horizontally through the tank, as electrical
resistance can easil send temperatures up to above 100'C if not
checked. Vents on the bottom are used to empty and fill the tank.

Concentrated brine (200-300 grams of sodium chloride to a liter
of water) is introduced into the cell, along with a small amount of
sodium or potassium dichromate (1-7 gms./liter) to hinder reduction
of the chlorate ion and protect the cathode against corrosion.
Dilute hydrochloric acid may also be added to set the pH of the
solution at 6 to 7. There is a potential drop of 3 to 4.5 volts across
each anode and a current often as high as 10,000 to 30,000
amperes per cell. [Assuming a 100 cell tank with 3.75 volts across
the anodes and cathode and 20,000 amperes flowing in each leg
as average values, Ohm's law would show a power consumption of
75 kilowatts, which would rather tend to discourage the amateur
experimenter! --Ed. (Van)] Temperature is held at or below 35'C,
as graphite anodes are most commonly used. If solution
temperature gets above 45'C, such anodes are seriously corroded
and oxidized away to carbon dioxide (catalyzed by the hydroxyl
ion). Graphite anodes are widely used because of low cost and
high efficiency-; but sometimes, more frequently in the past few
years, anodes of steel coated with lead dioxide (Pb02) or mag-
netite (Fe304) have been employed, since they can be used at
higher temperatures.

As solution level drops, more brine is added, until about 500 to
800 gms./liter have been added and 500 to 600 gms. of sodium
chlorate have been formed. Then the electrolyte is pumped out,
boiled, and treated with reducing agents like thiosulfate ion (the
"hypo" used in photographic darkrooms) to destroy remaining
hypochlorite ions, after which the solution is filtered to remove the
chloride ion. Next, evaporation to a smaller volume and chilling to
about 0o C separates the chlorate crystals. These may be bagged
for use elsewhere, converted by precipitation to another chlorate
salt, or put into a cell not unlike the chlorate cell and further oxi-
dized to form the perchlorate ion, which represents the highest
positive state into which chlorine can enter. Perhaps half of the
bagged chlorate may ultimately be converted back to chlorine gas
at its usage point, as that gas is used extensively to bleach textiles
and wheat flour.

In the production of perchlorates, the sodium salt is again
preferred over its potassium counterpart, as it is much more
water-soluble, allowing it to be more easily separated from sodium
chloride, and permitting the cell to be run longer between
drainings. Again, dichromate is added, and the pH is held at 6-7.
Voltages of 5 to 6.5 volts per anode are the most common. Here
the anodes are usually of platinum or of lead dioxide coated steel,
not graphite, for reasons of efficiency. Temperature is usually
40-60'C, and the cell is run until a concentration of 600-800 gms. of
sodium perchlorate per liter is achieved. The electrolyte is now
treated to remove dichromate and chlorate (barium carbonate is
useful), and the perchlorates of ammonium or potassium are
usually formed by double decomposition.

On a small-scale basis, successful chlorate/perchlorate
production is a real challenge, and this chemist was largely a
failure at the effort. The requirements of a high-amperage,
low-voltage power source largely rule out batteries on any
continuous basis. The common 6-volt battery charger is the most
convenient power source but suffers from lack of variability. The
large types used by garages can deliver an output of 50-100
amperes. The problem of varying the voltage might be solved by
use of a rheostat hooked in series with the positive or negative
output lead, but amperage would
(suffer.

The container, whether a beaker, battery jar or other vessel,
must possess several practical qualities: it must be capable of
being cooled, either with ice packs or, preferably, a continuous
stream; it must be resistant to corrosion (if not used as the
cathode), with glass or steel perhaps best qualifying for continuing
use; the top should be able to support connections to the anode
(and cathode) properly and vent the evolved gases without
exposing the operator to their often poisonous fumes (if used
indoors). If a separate cathode is used, platinum, platinized metal
or stainless steel (such as a large spoon) would be best. The
anode cannot be of copper, steel or other base metal, because of
the unbelievably corrosive action of chlorine and oxyacids
attacking it. So it must be of platinum, platinized metal, graphite
for chlorate production only) or lead-dioxide-coated graphite or
metal. Graphite anodes can be made from the central element of
large 1.5-volt dry cells, with the added convenience that they
already have a terminal attached. The local (or mail-order)
rockhound dealer can furnish platinized anodes, but platinum ones
will cost from $30 to $50 each. Stainless steel or graphite
elements can be plated with lead dioxide by making them -the
anodes in a bath of lead nitrate. A copper or steel cathode is used,
and a touch of copper sulfate or nitrate is added to the electrolyte
(see Ref. 2 below).

The clips to the electrodes must be shielded from the fumes or
covered with Saran-Wrap or other plastic to protect them from
corrosion. The electrolyte used for small-scale production is similar
to that described above for industrial use, although the salt
concentration may be less. If lead dioxide anodes are used,
chromate or dichromate should be omitted. If the anodes are made
of graphite and the electrolyte temperature should rise above
30-35'C, the solution will be filled with colloidal graphite. The
evolution of chlorine gas and chlorine dioxide can be minimized by
continual stirring and low temperature, but it may present a health
problem indoors and should be dealt with thoughtfully. Of course,
smoking around an electrolysis apparatus is a no-no!

On the basis of knowing the voltage and amperage between the
electrodes, one can calculate when the conversion to chlorate is
reasonably complete, using the relationship of electrical units to
molecular weight. One faraday (1 mole of electrons) = 96,500
coulombs; one coulomb = one ampere flowing for one second;
conversion to chlorate requires 6 faradays (-1 to +5 oxidation
number) per mole (107 grams).

Some "hypo" from the local camera supply shop can serve to
destroy excess hypochlorite after the remaining table salt crystals
have been separated away. The nitrates of barium and potassium
could be used to precipitate out most of the available chlorate from
a cold solution if it were not to be carried into perchlorate
production. Morton's Salt Substitute could supply potassium
chloride, but it is more expensive per pound than pyro-grade
nitrates. A slight saving in electricity and time could also be
effected by the use of commercially available bleach solutions,
which are 5 or 10 percent by weight of sodium hypochlorite, but the
cost of the bleach itself would tend to offset these savings. A more
concentrated hypochlorite can also be made by reaction of
household washing soda (sodium carbonate decahydrate) with
powdered 70% chlorine pool bleaches, e.g., HTH brand. Solutions
of alkaline earth chlorides or hypochlorites tend to electrolize less
efficently.

Overall, this writer found the biggest drawback of home
production of chlorates and perchlorates to be economics rather
than chemistry, time or safety factors. At today's outrageous prices
for electricity delivered to the home, often 25 cent to 32 cent per
kilowatt-hour, and considering that, at 3.6 volts, one pound of
sodium chlorate requires about 2.4 kilowatt-hours to produce, the
current retail prices don't seem quite so bad. And it takes about 3.6
to 4 kilowatt-hours to produce a pound of perchlorate, so the cost
is even more, in contrast to the usual market price of this chemical.
The home production of chlorates and perchlorates should perhaps
be considered a desperate last resort for the day when all
legitimate and practical sources of the commercial products may be
cut off. It's really much more fun making the compositions than the
chemicals!

REFERENCES FOR FURTHER STUDY:

1. Kirk & Othmer (Editors) ENCYCLOPEDIA OF CHEMICAL
TECHNOLOGY (Second Edition), interscience Publishers, New
York, 1963, Volume 8, "Chlorine Oxides". (an excellent guide to
this topic)

2. Hampel, Clifford A. (Editor) ENCYCLOPEDIA OF
ELECTROCHEMISTRY, Reinhold Publishing Co., New York, 1964.
(much practical information on lead dioxide electrode
manufacturing, chlorates, chlorine manufacturing and perchlorates)

3. Mantell, C. L., INDUSTRIAL ELECTROCHEMISTRY, McGraw
Hill, New York, 1931. (although dated, the book is filled with all
kinds of useful information on the manufacture of oxidizers by
electrolytic means)

4. Milazzo, Giulio, ELECTROCHEMISTRY: THEORETICAL
PRINCIPLES AND PRACTICAL APPLICATIONS, Elsevier, New
York, 1963. (probably the best and clearest guide to the chemical
and practical considerations of cell variables; should be available
in public libraries)

5.Schumacher, J. C., PERCHLORATES, Reinhold, New York
1960. (a thorough, monograph-like treatment, with much
information on electrolytic cells, hardware and processes, etc.)

=========================================================================
Date:         Mon, 22 Feb 1999 00:17:42 -0000
Reply-To:     Chemical Propulsion Research <CHEMROC@UGA.CC.UGA.EDU>
Sender:       Chemical Propulsion Research <CHEMROC@UGA.CC.UGA.EDU>
From:         Michael <mmcardle@IOL.IE>
Subject:      Re: CHLORATES AND PERCHLORATES reprint
MIME-Version: 1.0
Content-Type: text/plain; charset=ISO-8859-1
Content-Transfer-Encoding: 7bit

----------
> From: James E. Lanier <jelanier@BELLSOUTH.NET>
> To: CHEMROC@UGA.CC.UGA.EDU
> Subject: CHLORATES AND PERCHLORATES reprint
> Date: Sunday, February 21, 1999 3:37 PM
>
> I chose to post this reprinted article for those interested in chlorate and
> perchlorate synthesis. This may or may not be useful. (I see some flaws in
> the article in my area of expertise). It will at least give us cause for
> comment even if the procedures prove to be dated.
>
>
> Jim
>
>
>
> CHLORATES AND PERCHLORATES:
> THEIR PRODUCTION
>
> BY JAMES FINCKBONE
>
> American Pyrotechnist Fireworks News
> Volume 7, Number 6 June, 1974
>
>
><snip>
> ion, occurs only when all chloride has been removed or reacted, as
> its potential is of a higher value. The acidity (pH) of the solution will
> influence other side-reactions, such as the evolution of chlorine
> dioxide.

What pH favours chlorine dioxide evolution?

> years, anodes of steel coated with lead dioxide (Pb02) or mag-
> netite (Fe304) have been employed, since they can be used at
> higher temperatures.

Can magnetite electrodes be made by the non professional?

>
>   In the production of perchlorates, the sodium salt is again
>   preferred over its potassium counterpart, as it is much more
>   water-soluble, allowing it to be more easily separated from sodium
>   chloride, and permitting the cell to be run longer between
>   drainings. Again, dichromate is added, and the pH is held at 6-7.

pH, to the best of my knowledge, does not effect current effeciency when making
perchlorate.


> Voltages of 5 to 6.5 volts per anode are the most common. Here
> the anodes are usually of platinum or of lead dioxide coated steel,
> not graphite, for reasons of efficiency.

The graphite gets converted to CO2 at a high rate and the anode disintegrates too
rapidly.


> On a small-scale basis, successful chlorate/perchlorate
> production is a real challenge, and this chemist was largely a
> failure at the effort.

IMHO the biggest block for the small scale production of perchlorate is the obtaining
of
an insoluble anode.


The requirements of a high-amperage,
> low-voltage power source largely rule out batteries on any
> continuous basis. The common 6-volt battery charger is the most
> convenient power source but suffers from lack of variability. The
> large types used by garages can deliver an output of 50-100
> amperes. The problem of varying the voltage might be solved by
> use of a rheostat hooked in series with the positive or negative
> output lead, but amperage would
> (suffer.

 Cells in series will increase the needed power voltage and this might help in matching
the supply (with the cells) that the chemist has available.
Cells could also be put in parallel as another ploy to match the cells to the available
power supply characteristics if the supply has constant current characteristic.
The humble welder is a constant current supply with a variety of current outputs and can
be used to supply a fixed current to the cell or cells, and letting the voltage accross
the cells find its own level at the particular current density (anode/cathode),
temperature and solute concentration that the particular current dictates.
A capicitor would be recommended to smooth the voltage accross the cells.
There are a few different ways that current is limited in welders. I am not too sure
myself if adding a capicator accross the output is ok with all of them.

> The container, whether a beaker, battery jar or other vessel,
> must possess several practical qualities: it must be capable of
> being cooled, either with ice packs or, preferably, a continuous


If your current density (per liter of solution) is not too high cooling may not be
necessary.


> rockhound dealer can furnish platinized anodes, but platinum ones
> will cost from $30 to $50 each. Stainless steel or graphite

Can anybody tell me the price of platinum wire.
I would imagine that to purchase a large surface area of platinum would cost $$$$$$$$.

>    elements can be plated with lead dioxide by making them -the
>    anodes in a bath of lead nitrate. A copper or steel cathode is used,
>    and a touch of copper sulfate or nitrate is added to the electrolyte
>    (see Ref. 2 below).

Can't use sulphate as it will precipitate lead sulphate in the solution, nitrate is ok.

>    Some "hypo" from the local camera supply shop can serve to
>    destroy excess hypochlorite after the remaining table salt crystals
>    have been separated away. The nitrates of barium and potassium
>    could be used to precipitate out most of the available chlorate from
>    a cold solution if it were not to be carried into perchlorate
>    production. Morton's Salt Substitute could supply potassium
>    chloride, but it is more expensive per pound than pyro-grade

I have been adding Barium chloride to my chlorate/perchlorate solution to precipitate
chromates
(yellow colour) that are dissolved, I did not realise that BaCl would precipitate
Ba_chlorate.

,
Michael.

=========================================================================
Date:         Sun, 21 Feb 1999 20:38:28 -0500
Reply-To:     Chemical Propulsion Research <CHEMROC@UGA.CC.UGA.EDU>
Sender:       Chemical Propulsion Research <CHEMROC@UGA.CC.UGA.EDU>
From:         "James E. Lanier" <jelanier@BELLSOUTH.NET>
Subject:      Re: CHLORATES AND PERCHLORATES reprint
MIME-Version: 1.0
Content-Type: text/plain; charset="iso-8859-1"
Content-Transfer-Encoding: 7bit

-
>>    amperes. The problem of varying the voltage might be solved by
>>    use of a rheostat hooked in series with the positive or negative
>>    output lead, but amperage would
>>    (suffer.


This is wrong. This is no way to control output voltage to a load. If you
put 6 volts on a cell, the current is going to be what ever the cell
draws..period! If you had a 12 volts supply and added a series resistance
to get 6 volts on the cell, the current is the same as placing a 6 volt
supply across the cell. What is bad is efficiency. The current is the same
through the series resistance and hence a waste of power. (P=E^2/R) Also,
you have poor voltage regulation. As the cell demands more or less current,
the voltage would swing wildly across the cell.


>
> Cells in series will increase the needed power voltage and this might help
in matching
>the supply (with the cells) that the chemist has available.
>Cells could also be put in parallel as another ploy to match the cells to
the available
>power supply characteristics if the supply has constant current
characteristic.


Again, you must supply enough current to the cell based on what the cell
draws. If you are applying 6 volts to a cell and it only draws 1 amp, then
you need a supply capable of delivering 1 amp. If you want more current,
then you need more surface area to increase it. And you need a supply that
will deliver that higher amount of current. A supply that will deliver 1000
amps at 6 volts isn't going to increase the current in the cell unless the
cell draws it.
    A constant current supply is not desirable here. Constant current
implies increasing the voltage across the load if the impedance rises and
lowering the voltage when impedance falls. In electrochemical cells, the
cell voltages are chosen to get the desired results.
    I don't recommend capacitor input filters. The transformer peak currents
are high and duty cycle is low.

Jim


=========================================================================
Date:         Mon, 22 Feb 1999 21:41:14 -0000
Reply-To:     Chemical Propulsion Research <CHEMROC@UGA.CC.UGA.EDU>
Sender:       Chemical Propulsion Research <CHEMROC@UGA.CC.UGA.EDU>
From:         Michael <mmcardle@IOL.IE>
Subject:      Re: CHLORATES AND PERCHLORATES reprint
MIME-Version: 1.0
Content-Type: text/plain; charset=ISO-8859-1
Content-Transfer-Encoding: 7bit

>   >>   amperes. The problem of varying the voltage might be solved by
>   >>   use of a rheostat hooked in series with the positive or negative
>   >>   output lead, but amperage would
>   >>   (suffer.
>
>
>   This is wrong. This is no way to control output voltage to a load. If you
>   put 6 volts on a cell, the current is going to be what ever the cell
>   draws..period! If you had a 12 volts supply and added a series resistance
>   to get 6 volts on the cell, the current is the same as placing a 6 volt
>   supply across the cell. What is bad is efficiency. The current is the same
>   through the series resistance and hence a waste of power. (P=E^2/R) Also,
>   you have poor voltage regulation. As the cell demands more or less current,
>   the voltage would swing wildly across the cell.

I think what the author was saying was that if you were _stuck_ with, say, an 8V supply
and this was putting too much current into your cell (too much heat or too high a current
density on the anode) then putting a resistor in series would get you away, two volts
(say) will get dropped accross the resistor and you will now have a supply which has
a
6V output which is what you wanted. ( I just assuming for this argument that we want 6V)
The new supply (old supply + resistor ) will now have a worse voltage regulation and will
waste power as you said James.


>
>
>   >
>   > Cells in series will increase the needed power voltage and this might help
>   in matching
>   >the supply (with the cells) that the chemist has available.
>   >Cells could also be put in parallel as another ploy to match the cells to
>   the available
>   >power supply characteristics if   the supply has constant current
>   characteristic.
>
>
>   Again, you must supply enough current to the cell based on what the cell
>   draws. If you are applying 6 volts to a cell and it only draws 1 amp, then
>   you need a supply capable of delivering 1 amp. If you want more current,
>   then you need more surface area to increase it. And you need a supply that
>   will deliver that higher amount of current. A supply that will deliver 1000
>   amps at 6 volts isn't going to increase the current in the cell unless the
>   cell draws it.
>       A constant current supply is not desirable here. Constant current
>   implies increasing the voltage across the load if the impedance rises and
>   lowering the voltage when impedance falls.

Does it really matter if voltage varies a bit as long as its high enough and you are not
too concerned with a bit of *power wastage.
I run a cell at about 25 amps with no cooling (75C) with the welder.
If I was to go out in the morning and get myself a constant voltage supply which would
deliver
 the wanted current and I was to set this constant voltage supply up with the same cell
and set the voltage to put 25A (same current) through my cell,that voltage would be the
same as the voltage that the constant current supply is causing accross my cell at the
moment.
With the constant voltage supply you would have to keep an eye on the current and go out
every few days and slightly increase the voltage to keep the current at 25A (assuming
you
wanted to have the current fearly constant to figure out what your eventual amper hours
was at the end of the run). With the constant current supply you can forget about it and
know that at the end of the run that it is a matter of saying; I have run my cell for
(say) 20 days at 25A.
With the constant voltage supply the current will varie if you do not keep tweaking the
voltage.
Perhaps the current would vary only a little, I dont know myself.
How much will the current vary does anybody know?
What are the characteristics of power supplies used in industry?

* In industry the power wastage is appparantly hugh. The cells have coils of cooling
pipes going through them, but I think that the need for the cooling has more to do with
the fact that
the current density per liter volume of solution is high to keep the cell size small and
therefor the cell alone is not bit enough to dissapite the power.


When making perchlorate (I dont know about chlorate) the current efficiency also
increased as the anode current density increases (to a point) so that is a further
incentive to keep the current high.
Does increasing the current concentration per liter volume of solution increase the
current effeciency does anybody know or it just to save space that the current density
per liter is high in industry.


>In electrochemical cells, the
> cell voltages are chosen to get the desired results.

This is something that I am a little shakey on.
Whem one says that "the cell voltages are chosen to get the desired results"
what does one actually mean.
There is a certain min. voltage that must be supplied to get the desired reaction to
take place
and I would imagine that if you were to supply this min. voltage to the cell the current
that would actually flow would be considered too low for the manufacturing process to
be
complete in a reasonably time frame.
The voltage in increased above this min. voltage (theoritical for the reaction to take
place) in order to get the run times for the cells lower.
There will be a point at which the wasted power in the cells and the bother in cooling
the cells will cost more than the extra savings in time.
Can anybody tell me what is the voltage needed too convert the chloride to hypochlorite,
the hypochlorite into chlorate, and lastly the chlorate into perchlorate.
I believe that the first two are the same.
There is probably no exact voltage (theoritical or practical) that one can give as the
reaction rate is probably increased more and more as the voltage in increased thuough
a
range of values above the theoritical min. much like the way that reactions increase as
temperature increases
  by the Arrhenius rate equation.
I am totally out of my depth discussing this but what I am trying to say is that the
voltage that is to be applied accross a cell is dictated first and foremost by the
theoritical mim. that is needed to make the reaction take place and them some more
voltage will be applied to help make the process more economical in time (which is
money), as more current will flow.



>     I don't recommend capacitor input filters. The transformer peak currents
> are high and duty cycle is low.
>
> Jim

That is true but if you have a welder to hand and you dont want to purchase another
supply
it will get you away if the weder is able to supply say 100A and you are running at an
average current of say 20A.
I have a welder to hand which supplies 25 amps min (thats the min ) it has a max of 180
amps.
Its a constant current supply, at least when you ask it to supply a load that has 3 to
7V
accross it, it has 80V open circuit voltage. If the 25 amps is too much for your cell
(too high a current density on the anode)
then you can consider putting two cells in parallel and say increasing the current out
of
the welder to 40amps and you will get 20A through each cell (reduced from 25A)
It may be difficult to get the current to distribute evenly between the two cells.

The whole artical was written in the spirit that it was the 'home' chemist that was doing
the work and therefor had to try and make do with the power supplies that he/she had to
hand.

Michael.


=========================================================================
Date:         Mon, 22 Feb 1999 18:57:05 -0500
Reply-To:     Chemical Propulsion Research <CHEMROC@UGA.CC.UGA.EDU>
Sender:       Chemical Propulsion Research <CHEMROC@UGA.CC.UGA.EDU>
From:         "James E. Lanier" <jelanier@BELLSOUTH.NET>
Subject:      Re: CHLORATES AND PERCHLORATES reprint
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>>In electrochemical cells, the
>> cell voltages are chosen to get the desired results.
>
>This is something that I am a little shakey on.
>Whem one says that "the cell voltages are chosen to get the desired
results"
>what does one actually mean.
>There is a certain min. voltage that must be supplied to get the desired
reaction to
>take place
>and I would imagine that if you were to supply this min. voltage to the
cell the current


Yes, this is a strange concept. Consider this..Place a power supply of say
12 volts on the cell with a 1K resistor in series to make a trickle charger.
Later, remove the supply and measure the voltage across the cell. (ie the
cell is a battery now). This is the reversible potential of the cell. The
voltage to make things happen has to be at least infinitesimally larger than
this to make a current flow. If the voltage were too high, excessive gassing
would result and maybe undesired products. It is my belief that industry
chooses a happy medium that results in good efficiency with minimal tertiary
products. Keep in mind that this is an educated guess. I can't speak for
industry here. I remember speaking to a very accomplished electrochemist
here on campus and he freaked out when I mentioned potentials of 5-6 volts.
Considering the value of reversible potentials, I see his point. Remember
that the voltage drops near the electrodes are still small. (I have measured
this)
One thing I would like to know is...Why does platinum work..but gold
doesn't. Any takers?

Jim

=========================================================================
Date:         Mon, 22 Feb 1999 19:14:48 +500
Reply-To:     weaver_r@mediasoft.net
Sender:       Chemical Propulsion Research <CHEMROC@UGA.CC.UGA.EDU>
From:         Richard Weaver <weaver_r@MEDIASOFT.NET>
Subject:      Re: CHLORATES AND PERCHLORATES reprint
Comments: To: "James E. Lanier" <jelanier@BELLSOUTH.NET>

James E. Lanier asked:

>One thing I would like to know is...Why does platinum work..but gold
>doesn't. Any takers?
>


That's an easy one...I tried it...gold dissolves. (I was using only 14k though)
I guess 24k would have lasted longer but I think it would have still dissolved.
I was thinking about trying gold leaf at one point but didn't. I think a (real
gold) leaf is somewhere around $5.

Rich

=========================================================================
Date:         Tue, 23 Feb 1999 14:27:32 +0000
Reply-To:     Chemical Propulsion Research <CHEMROC@UGA.CC.UGA.EDU>
Sender:       Chemical Propulsion Research <CHEMROC@UGA.CC.UGA.EDU>
From:         Wouter Visser <w.f.visser@STUD.CHEM.UU.NL>
Subject:      Re: perchlorate
Mime-Version: 1.0
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Michael wrote:
>What pH favours chlorine dioxide evolution?

High pH does.

>pH, to the best of my knowledge, does not effect current effeciency
>when making perchlorate.

While I believe you are right, many articles mention the use of pH control.
(it is usually kept slightly acidic, like in chlorate manufacture). There
must be a reason.
>IMHO the biggest block for the small scale production of perchlorate is
>the >obtaining of an insoluble anode.


That, and the continues maintanance required because of cell

>Can anybody tell me the price of platinum wire.
>I would imagine that to purchase a large surface area of platinum would
>cost >$$$$$$$$.

The best prices I could find:

wire   0.1   mm diameter    $36 per meter
wire   0.2   mm              45
wire   0.3   mm              58
wire   0.5   mm              94

These are approximate, as they were converted from guilders to dollars and
rounded.
>From this, 1 square centimeter of surface area will costs you approx $11.5
in 0.1 mm wire, $7.2 in 0.2 mm wire, $6.2 or $6 in 0.5 mm wire

So from this trend, unexepectly, it seems more cost effective to buy
thicker wire. It could well be though that the trend does not continue
(much) beyond 0.5 mm.

Jim wrote:
>    A constant current supply is not desirable here. Constant current
>implies increasing the voltage across the load if the impedance rises and
>lowering the voltage when impedance falls. In electrochemical cells, the
>cell voltages are chosen to get the desired results.

There is a minimum voltage required to get the reaction going and everything
above that is going to increase the current flowing according to ohms's law.
So it does make sense to have a constant current supply. A constant current
implies a constant reaction rate.

Wouter.

=========================================================================
Date:         Tue, 23 Feb 1999 18:32:19 -0000
Reply-To:     Chemical Propulsion Research <CHEMROC@UGA.CC.UGA.EDU>
Sender:       Chemical Propulsion Research <CHEMROC@UGA.CC.UGA.EDU>
From:         Michael <mmcardle@IOL.IE>
Subject:      Re: perchlorate
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----------
> From: James E. Lanier <jelanier@ARCHES.UGA.EDU>
> To: CHEMROC@UGA.CC.UGA.EDU
> Subject: Re: perchlorate
> Date: Tuesday, February 23, 1999 3:16 PM
>
> >So it does make sense to have a constant current supply. A constant current
> >implies a constant reaction rate.
>
>
> Excessive gassing decreases current flow...voltage rises...a run-away
> condition.

You pick a suitable constant current, for example about 4 amps per DM^2 (ANODE).
This will not give too high a voltage accross the cell. If gassing should increase at
say
the end of the run when salt (or chlorate if its a perchlorate cell)
concentration is low, you will simply get a bit more voltage accross your cell.
You wont get a runaway condition.

Michael.

=========================================================================
Date:         Tue, 23 Feb 1999 18:44:36 -0000
Reply-To:     Chemical Propulsion Research <CHEMROC@UGA.CC.UGA.EDU>
Sender:       Chemical Propulsion Research <CHEMROC@UGA.CC.UGA.EDU>
From:         Michael <mmcardle@IOL.IE>
Subject:      Re: CHLORATES AND PERCHLORATES reprint
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>
>   >>In electrochemical cells, the
>   >> cell voltages are chosen to get the desired results.
>   >
>   >This is something that I am a little shakey on.
>   >Whem one says that "the cell voltages are chosen to get the desired
>   results"
>   >what does one actually mean.
>   >There is a certain min. voltage that must be supplied to get the desired
>   reaction to
>   >take place
>   >and I would imagine that if you were to supply this min. voltage to the
>   cell the current
>
>
>   Yes, this is a strange concept. Consider this..Place a power supply of say
>   12 volts on the cell with a 1K resistor in series to make a trickle charger.
>   Later, remove the supply and measure the voltage across the cell. (ie the
>   cell is a battery now). This is the reversible potential of the cell. The
>   voltage to make things happen has to be at least infinitesimally larger than
>   this to make a current flow. If the voltage were too high, excessive gassing
>   would result and maybe undesired products. It is my belief that industry
>   chooses a happy medium that results in good efficiency with minimal tertiary
>   products. Keep in mind that this is an educated guess. I can't speak for
>   industry here. I remember speaking to a very accomplished electrochemist
>   here on campus and he freaked out when I mentioned potentials of 5-6 volts.
>   Considering the value of reversible potentials, I see his point. Remember
>   that the voltage drops near the electrodes are still small. (I have measured
>   this)


Since you need a higher voltage to make perchlorate does it follow that if you examine
the reverce potential of a perchlorate cell that it will be higher than a chlorate cell.
Is the potential you measure with this suitration reallly a measure of the voltage needed
too make the actual wanted reaction happen. Any salt dissolved in water with two
disimiler metals (or one conduvtive and the other a metal) in it will show a potential
like a battery , it is in fact a battery.
I think there is a diffference between getting a current to flow and having the current
flowing and also the proper min. voltage accross the cell.
IMHO BTW.

Michael.
=========================================================================
Date:         Tue, 23 Feb 1999 15:11:45 -0500
Reply-To:     Chemical Propulsion Research <CHEMROC@UGA.CC.UGA.EDU>
Sender:       Chemical Propulsion Research <CHEMROC@UGA.CC.UGA.EDU>
From:         "James E. Lanier" <jelanier@BELLSOUTH.NET>
Subject:      Re: CHLORATES AND PERCHLORATES reprint
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>
>
>Since you need a higher voltage to make perchlorate does it follow that if
you examine
>the reverce potential of a perchlorate cell that it will be higher than a
chlorate cell.
>Is the potential you measure with this suitration reallly a measure of the
voltage needed
>too make the actual wanted reaction happen. Any salt dissolved in water
with two
>disimiler metals (or one conduvtive and the other a metal) in it will show
a potential
>like a battery , it is in fact a battery.
>I think there is a diffference between getting a current to flow and having
the current
>flowing and also the proper min. voltage accross the cell.
>IMHO BTW.
>
>Michael.


 As I had previously stated, the reversible potentials are very low. ANY
voltage higher than this causes a current to flow. Everything happens at the
electrode. The voltage that is placed across the cell simply has to be
higher than the reversible potential. If, for example, the reversible
potential was 1 volt and you had decided that an appropriate current density
required 5 amps total to flow. The power supply voltage would be raised
until you get that value of current. Lets say it happened to be 5 volts.
Then we know that 4 additional volts are dropped across electrolyte. This
of course is an additional 20 watts of heat. So...the voltage is chosen to
get the desired current. As far as "what is optimum for chlorates and
perchlorates"..I don't know.


Jim
=========================================================================
Date:         Tue, 23 Feb 1999 18:33:56 +500
Reply-To:     weaver_r@mediasoft.net
Sender:       Chemical Propulsion Research <CHEMROC@UGA.CC.UGA.EDU>
From:         Richard Weaver <weaver_r@MEDIASOFT.NET>
Subject:      Re: CHLORATES AND PERCHLORATES reprint
Comments: To: "James E. Lanier" <jelanier@BELLSOUTH.NET>

>>Since you need a higher voltage to make perchlorate does it follow that if

>you examine
>>the reverce potential of a perchlorate cell that it will be higher than a

>chlorate cell.
>>Is the potential you measure with this suitration reallly a measure of the

>voltage needed
>>too make the actual wanted reaction happen. Any salt dissolved in water
>with two
>>disimiler metals (or one conduvtive and the other a metal) in it will show

>a potential
>>like a battery , it is in fact a battery.
>>I think there is a diffference between getting a current to flow and having

>the current
>>flowing and also the proper min. voltage accross the cell.
>>IMHO BTW.
>>
>>Michael.
>
>
> As I had previously stated, the reversible potentials are very low. ANY
>voltage higher than this causes a current to flow. Everything happens at the

>electrode. The voltage that is placed across the cell simply has to be
>higher than the reversible potential. If, for example, the reversible
>potential was 1 volt and you had decided that an appropriate current density

>required 5 amps total to flow. The power supply voltage would be raised
>until you get that value of current. Lets say it happened to be 5 volts.
>Then we know that 4 additional volts are dropped across electrolyte. This

>of course is an additional 20 watts of heat. So...the voltage is chosen to

>get the desired current. As far as "what is optimum for chlorates and
>perchlorates"..I don't know.
>

This whole discussion is a bit too narrow. If you over drive the voltage, locally
you will get an environment that is different from the rest of the electrolyte,
especially with bubbles and voids in the anode. The local environments can give
rise to other reactions. You can get perchlorate in a chlorate cell, oxygen
gas, ozone gas, etc and maybe you are only trying to make hypochlorite bleach.
According to my college chemistry book, with stirred electrolyte, sodium hypochlorite
will be produced to completion [without chlorate] if the proper voltage is held.
This seems imposible if the voltage required for chlorate is the same.

Consider a very long narrow cell with the anode and cathode on opposite ends.
No stirring allowed. Start with a pure NaCl solution. When you run this cell,
the electrolyte around the anode will soon deplete the Cl. O2 would then start
to form unless some OH gets there to capture some Cl2. It doesn't matter that
Cl is still present in the middle while NaOH is forming on the other end.

Untreated carbon rods die because electrolyte is trapped in the pores of the
anode and get depleted of Cl and ClO3 and O2 forms oxidizing the carbon [this
is from a book I have on graphite]. I also believe perchlorate crystals are
formed if KCl is used in the cell. I think these rip apart the carbons like
ice in rocks.

Then there is the overpotential issue. Depending on the overpotential of the
anode, O2 may or may not be created. If you jack the voltage up high enough,
the overpotential will be overcome and the gas will form. This reaction will
not be represented when hooking the cell up as a battery.

If you jack the voltage up high enough, steam will form if the electrodes get
real hot. Or you might get arching and ozone.

Rich

=========================================================================
Date:         Tue, 23 Feb 1999 20:59:47 -0600
Reply-To:     Chemical Propulsion Research <CHEMROC@UGA.CC.UGA.EDU>
Sender:       Chemical Propulsion Research <CHEMROC@UGA.CC.UGA.EDU>
From:         Terry McCreary <terry.mccreary@MURRAYSTATE.EDU>
Subject:      Re: CHLORATES AND PERCHLORATES reprint
Mime-Version: 1.0
Content-Type: text/plain; charset="us-ascii"

>>of course is an additional 20 watts of heat. So...the voltage is chosen to
>>get the desired current. As far as "what is optimum for chlorates and
>>perchlorates"..I don't know.

Nor do I. That's the sort of thing is probably determined by trial, error,
and a little black magic.
>According to my college chemistry book, with stirred electrolyte, sodium
hypochlorite
>will be produced to completion [without chlorate] if the proper voltage is
held.
>This seems imposible if the voltage required for chlorate is the same.


That may be an oversimplification on the part of the author (who may
genuinely not know). FWIW here are some reduction potentials:

Cl2 + 2e -> 2 Cl- 1.36V
HClO + H+ + 2e -> Cl- + H2O  1.48V
ClO- + H2O + 2e -> Cl- + 2 OH-      0.81V
ClO2- + 2H2O + 4e -> Cl- + 4 OH-      0.76V
ClO3- + 6H+ + 6e -> Cl- + 3H2O     1.45V
ClO4- + 8H+ + 8e -> Cl- + 4H2O      1.39V

On the face of it, it would appear that the fourth reaction would be most
favored, requiring the lowest potential to occur. But on a given electrode
surface, there is a certain overvoltage needed to cause the reaction to
actually occur. The overvoltage varies with the half-reaction and with the
electrode surface. 0.76 V vs. the standard hydrogen electrode may be
sufficient to cause chlorite ion to form. Or it may not.

So I don't know whether one could expect to form nothing but chlorate in
such a cell, especially considering the potential of the fourth half-reaction.

P'rfesser

=========================================================================
Date:         Wed, 24 Feb 1999 06:33:11 -0500
Reply-To:     weaver_r@mediasoft.net
Sender:       Chemical Propulsion Research <CHEMROC@UGA.CC.UGA.EDU>
From:         Rich Weaver <weaver_r@MEDIASOFT.NET>
Organization: At home in the mountains
Subject:      Re: CHLORATES AND PERCHLORATES reprint
MIME-Version: 1.0
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Terry McCreary wrote:

>   I wrote:
>   >According to my college chemistry book, with stirred electrolyte, sodium
>   hypochlorite
>   >will be produced to completion [without chlorate] if the proper voltage is
>   held.
>   >This seems imposible if the voltage required for chlorate is the same.
>
>   That may be an oversimplification on the part of the author (who may
>   genuinely not know).

James E. Brady and Gerard E. Humiston, General Chemistry Principles and
Structures, third edition (C) 1982 by John Wiley & Sons, Inc. ISBN 0-471-07806-9
(know anything about these guys and their reputation for truth and
knowledge/research?)

page 524 (bottom)

"If the electrolysis of brine is carried out in a vigerously stirred solution,
the OH- produced at the cathode reacts with the Cl2 formed at the anode. The
raction is
Cl2 + 2OH- -> Cl- + OCl- + H2O
Continued electroylsis therefore gradually converts nearly all the chloride ion
to hypochlorite ion, OCl- and the sodium chloride solution is changed to a
solution of sodium hypochlorite. When diluted to about 5 to 6 percent by weight,
this is sold as liquid laundary bleach (e.g., Clorox(R))"

I guess my memory of the passage wasn't quite perfect.

Page 641 talks about hyophalites disproportionating to halites and halates
automatically with time. It states that disproportionation of OCl- is slow at
room temp.

I would expect an old bottle of bleach to contain chlorate unless some
contaminant is present to prevent it. Over a year ago, I added some KMnO4 to a
fresh bottle of Clorox. The color is still the same as when I added the KMnO4.
(Not so for the KMnO4 I added to ammonia. I am told the KNO3 and MnO2 are
formed.) However, I am not sure since I can't see through the jug if any
crystals of KClO3 have formed or not. Since it is outside and the temperature is
17F, I should decant it and check. Sounds like a good morning project. I'll let
you know what I find after it gets light.

>   FWIW here are some reduction potentials:
>   Cl2 + 2e -> 2 Cl-     1.36V
>   HClO + H+ + 2e -> Cl- + H2O          1.48V
>   ClO- + H2O + 2e -> Cl- + 2 OH-              0.81V
>   ClO2- + 2H2O + 4e -> Cl- + 4 OH-              0.76V
>   ClO3- + 6H+ + 6e -> Cl- + 3H2O             1.45V
>   ClO4- + 8H+ + 8e -> Cl- + 4H2O              1.39V
>
>   On the face of it, it would appear that the fourth reaction would be most
>   favored, requiring the lowest potential to occur. But on a given electrode

Which, with H2O converts to 2 and 3, see the referenced diagram below. Perhaps
it is too unstable to exist for any length of time.

> surface, there is a certain overvoltage needed to cause the reaction to
> actually occur. The overvoltage varies with the half-reaction and with the

Who knows what the overpotentials are with different anode materials for wach of
these substances. That changes the whole picture. These are half reactions with
a hydrogen reference, not carbon, PbO2 or Pt.

>   electrode surface. 0.76 V vs. the standard hydrogen electrode may be
>   sufficient to cause chlorite ion to form. Or it may not.
>
>   So I don't know whether one could expect to form nothing but chlorate in
>   such a cell, especially considering the potential of the fourth half-reaction.

My cells always smell like and act like bleach early in the run. Separating
chlorate crystals via filtering of a hot solution is frot with problems as the
bleach causes the coffee filters to turn to pulp. I hear lab filters fare much
better. I've thought of using fiberglass cloth and ditomaceous earth but have
since abandoned filtering altogether in favor of decanting a warm solution. Its
even eaten holes in those gold plated SS mesh permanent coffee filters.

Check out http://homepages.infoseek.com/~kclox/MBPages/kclo4i.htm The bottom of
the page has an interesting diagram. Seems # 2, 3 and 4 all are the same
oxidation state. Perhaps that has something to do with it. I don't know what the
text describing this diagram stated (It would be nice).

Rich

=========================================================================
Date:         Fri, 26 Feb 1999 02:40:25 -0000
Reply-To:     Chemical Propulsion Research <CHEMROC@UGA.CC.UGA.EDU>
Sender:       Chemical Propulsion Research <CHEMROC@UGA.CC.UGA.EDU>
From:         Michael <mmcardle@IOL.IE>
Subject:      pH and species.
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Hello all,
Enclosed is a graph showing the concentrations of species in a chlorate cell with pH.
The optimum is 6.8 and this is used in industry.
For the home chemist the bother and cost of adding HCl to keep the pH at 6.8 is not worth
the hassle, and cost of HCl.
The pH rise is caused by the excape of chloring gas from the cell.
As the pH rises the chlorine finds it harder and harder to actually excape form the cell
with the result that the cell stabalised at a pH determined by the physical nature of
the
cell.
If you have the anode and cathode spaced laterally far apart the intermedieates cannot
come into contact with each other as easily as if the anode and cathode were close
together
and your cell pH will rise up to a higher pH before it will stabalise.
Some recommend putting the cathode below the anode so that hydrogen coming from the
cathode will sweep the wanted cathode products into contact with the chlorine coming from
the anode and hopefully creat a cell that will stabalise at a lower pH than it might
otherwise do.
The cell where pH is not being controlled by HCl will stabalise at about pH = 9 TO 12.
Looking at the graph it would seem that when your pH rised above about 9 there will be
no
chlorate forming from the so called bulk, effecient, reaction (5) (the reaction that does
not need electrons to be supplied) and all chlorate will be formed by electricity. First
the chlorine is produced at the anode and some intermediate products form spontanously,
to give the hypochlorite species which will be churned into chlorate using more electrons
from supply
via reaction (7), so called ineffecient reaction.


 We would like all our chlorate to form via reaction (5) which has its optimum at pH of
6.8 because there will be the greatest concentrations of wanted 'ingredients for the
reaction' and at the proper proportions at that pH.(see the graph)
If you could get all of the chlorate to form via reaction (5) and get no oxygen evolution
then you would have 100% current effeciency.(damm near, there may be other minor
reactions that I am unaware of {CO2 if using graphite for example}).

The overall reaction as far as electrons is concerned is that it takes 6 electrons to
make one NaCl (salt) molecule into one chlorate molocule if all of the reaction goes by
(2) and then (5). Thats 100% current efficiency.
If some or all of the chlorate is formed by reaction (7) then the current effeciency will
be lower.


If you were to form ALL of the chlorate by reaction (7) (reaction 1 and 2 must happen
first) what will be the current efficiency be?
I cannot figure it out for myself from the equations (for the life of me).!
Assum no other inefficiencies like O2 evolution etc.


_______________________________________________



Reaction Equations (from Mike Browns page)

There are two simultaneous processes of chlorate production that occur in the
electrolysis of aqueous chloride. The first, and most efficient, is the so called
Foerster reaction. The first step is the oxidation of chloride at the anode with
immediate hydrolysis of the anode product (chlorine) to yield the hypochlorous species,
HClO and ClO-. The chloride to chlorate conversion requires about 3.3 volts.

(1)Overall Foerster Reaction:NaCl + 3H2O -> NaClO3 + 3 H2
(2a) Anode: 2 Cl- -> Cl2 + 2e-
(2b) Cathode: 2H2O + 2e- -> H2 + 2OH-

(3) Bulk Soln: Cl2 + H2O -> HOCl + H+ + Cl-

(4) Bulk Soln: HOCl <-> ClO- + H+

(5) Bulk Soln: 2HClO + ClO- + H2O -> ClO3- + H3O+ + 2Cl-

There are also the two side reactions that reduce the current efficiency. Number six is
common in aqueous electrolysis and can sometimes be avoided by chosing an anode with a
high overpotential for O2, a short list of which is given on the persulfate page.

(6) Anode: 2H2O + 2e- -> O2 + 4H+ + 4e-

Reaction number seven is the electrochemical oxidation of hypochlorite at the anode, and
certainly not what one would intuitively consider to be a waste of electricity because
it
does yield the product that we're all after. It is considered a waste because the only
electricity required to get the ClO3- is that needed to drive rxn (2).

(7) Anode: 6OCl- + 9H2O -> 2ClO3- + 6H3O+ + 4Cl- + 3/2O2

(8) Overall:2Cl- + 18 OH- -> 2ClO3- + 9H2O + 3/2O2 + 18 e-

__________________________________________________________

Appoligies for bringing up this old chestnut again but its that damm graph that got me
going!
I would like to think that most (all indeed) of the above is correct but would be
grateful for any contradictions or corrections.

It is very hard to figure out from looking at the equations where the 6 electrons per
molecule of chlorate are accounted for. Or is it just my inept head.

What I was going to say at the start and I have nearly forgot was that temperature helps
speed up the bulk reactions, but if you are running your cell at pH 9 or so then I see
very little advantage in having a hot cell as there will simply be no species to react
together at the high pH.
In industry the cell temperatures when using lead dioxide anodes are in the region of
70C
I believe. Are these temperatures desirable for to help the bulk reactions to take place
(remenber the pH in industry is controlled) or is the temperature that critical at all.
Would the cell simply be run at 70C simply because that is a convenient temperature to
keep it at without excesseve cooling gear, with the cell not being excessively hot as
to
make evaporation a problem.
(High temperature also lowers voltage accross the cells giving less power consumption.)



Cheers,
Michael.

=========================================================================
Date:         Fri, 26 Feb 1999 10:56:30 -0800
Reply-To:     Chemical Propulsion Research <CHEMROC@UGA.CC.UGA.EDU>
Sender:       Chemical Propulsion Research <CHEMROC@UGA.CC.UGA.EDU>
From:         John LeBourgeois <arcmight@EMAIL.MSN.COM>
Subject:      Igniters, EBF's etc..
In-Reply-To: <36D60BCD.1696@michianatoday.com>
MIME-Version: 1.0
Content-Type: text/plain; charset="iso-8859-1"
Content-Transfer-Encoding: 7bit
> -----Original Message-----
> CATS?

Cheap Access To Space

>
> > My current work is designing a boron Kno3 ignition system
>
> Why these two chems in particular?

  Boron and KNO3 produce a good balance between Flame Temperature, hot
particles and low shock wave that allows HTPB composite systems to reliably
ignite with multiple burning surfaces w/o shocking the propellant or
inducing fractures in the grain surface as can sometimes occur with Al +
KClO4 ignition systems. The boron throws a lot of hot particulate material
around that really does the job, plus you can avoid over pressurizing the
system with it. It is used in military igniters, there's a web site on the
hellfire missle that has info on it. The common military surface to
thickness burning area is approximated by a standard 5 grain bayer asprin.

  Note that crystalline boron is inert, you need to use powdered or
amorphous boron


=========================================================================
Date:         Mon, 8 Mar 1999 07:27:28 -0800
Reply-To:     Chemical Propulsion Research <CHEMROC@UGA.CC.UGA.EDU>
Sender:       Chemical Propulsion Research <CHEMROC@UGA.CC.UGA.EDU>
From:         Kent Richman <KRichman@APFC.COM>
Subject:      Re: Chlorate destruction
MIME-Version: 1.0
Content-Type: text/plain

We use sodium metabisulfite. It's cheap, relatively safe, and the
products are easily removed.

> -----Original Message-----
> From: Michael [SMTP:mmcardle@IOL.IE]
> Sent: Friday, March 05, 1999 6:55 PM
> To:   CHEMROC@UGA.CC.UGA.EDU
> Subject:      Chlorate destruction
>
> Hello all,
>
> Can anybody tell me what to use to eliminate the last traces of sodium
> chlorate from my
> sodium perchlorate batch before I convert it into ammonium
> perchlorate.
> I don't want any ammonium chlorate forming.
>
Michael Mc Ardle.

=========================================================================
Date:         Sat, 13 Mar 1999 21:21:18 EST
Reply-To:     Chemical Propulsion Research <CHEMROC@UGA.CC.UGA.EDU>
Sender:       Chemical Propulsion Research <CHEMROC@UGA.CC.UGA.EDU>
From:         Gary Dwyer <MARSTEC@AOL.COM>
Subject:      Re: AN/AP
Mime-Version: 1.0
Content-type: text/plain; charset=US-ASCII
Content-transfer-encoding: 7bit

In a message dated 3/13/99 9:09:23 AM Mountain Standard Time,
aborza@NETZERO.NET writes:
> I have been trying to use AN in simple formulations with very little
> success. I am very interested in having a discussion with anyone about
their
> experience using AN in low signature (non-metallic) motors .
>
AB,
  I build and fly AN motors on a monthly basis and it works. The formula is
60/20/20 mag,AN,R-45. Yes, they can be very hard to ignite, I have to build
very hot igniters for these. I use this in PVC chambers, so I'm limited to
about 500 psi, just enough to get me up and going. There is a company called
CP Technologies that sells a book and software that helps you figure out a lot
of stuff, they also sell the PSAN that you may use if your looking to store
the motors for any length of time.

 Gary

=========================================================================
Date:         Mon, 15 Mar 1999 01:12:36 +0100
Reply-To:     "Javier D." <javier.d@teleline.es>
Sender:       Chemical Propulsion Research <CHEMROC@UGA.CC.UGA.EDU>
From:         "Javier D." <javier.d@TELELINE.ES>
Subject:      AN/AP   the best ----- the worst
Comments: To: arocket@nmt.edu
MIME-Version: 1.0
Content-Type: multipart/alternative;
              boundary="----=_NextPart_000_0028_01BE6E80.E98F3B60"

This is a multi-part message in MIME format.

------=_NextPart_000_0028_01BE6E80.E98F3B60
Content-Type: text/plain;
        charset="iso-8859-1"
Content-Transfer-Encoding: quoted-printable

Hello,
I am working with AN   six month ago, I have select the AN for this =
reason :

AN

The Best                                                         The =
worst

Cheap                                                         Higroscopy       =
=20
Easy to find                                                The phase =
change
Not toxic                                                      Dificult =
to ignite
Very stable                                                  Low density
High ISP
  =20

AP

High ISP                                                       Expensive
High density                                                 Dificult to =
find
Esy to ignite                                                 HCl=20
                                                                         Low =
igniting point =20

In Spain the AP cost about 30$ USD/Kg.

You can read the IBM patent   4.158.583 but I have change the 12% HTPB     =
with 17% HTPB or Epoxy,
The most common catalizer is Potassium Dichromate ( are a little =
toxic=3D HTPB=3D Epoxy aromatics amines )
Is very important use the catalizer increase the burn rate and easy to =
ignite, I work with this formula :

  AN          60%
  AP          10%
  PD            3%
  AL              7%
  Mg            3%
 HTPB   17%

If you use a graphite nozzle you can increase the metalic fuel, this =
mixture have a theoretical temperature 2400K, I use a ceramic insertion =
with 2600K maximun temperature work. =20

Javier D.

 =20

=========================================================================
Date:         Tue, 6 Apr 1999 10:30:52 -0500
Reply-To:     Chemical Propulsion Research <CHEMROC@UGA.CC.UGA.EDU>
Sender:       Chemical Propulsion Research <CHEMROC@UGA.CC.UGA.EDU>
From:         Terry McCreary <terry.mccreary@MURRAYSTATE.EDU>
Subject:      Re: formulas
Mime-Version: 1.0
Content-Type: text/plain; charset="us-ascii"

Here's one I've been working with:

150 g 200 micron AP
75 g 400 micron AP
3 g CuO
48 g PBAN
9 g DER331 epoxy

All chemicals available from Firefox. Must be processed and cured at 55-65
deg C; even at that temp it's like cold peanut butter. Cure time is 2-4
days at this temperature. Sticks nicely to paper casting tubes; no
treatment of the tubes required.

I've not been using vacuum processing; density has been about 0.053-0.054
lb/in^3, a bit over 90% of theoretical. It burns rather quickly. The 29mm
phenolic XX casings from McMaster-Carr give way above Kn=200. It has worked
down to Kn=140; I haven't tried lower area ratios yet.

Nice blue flame with a trace of black smoke.   Very easy to ignite.

P'rfesser

=========================================================================
Date:         Tue, 20 Apr 1999 11:08:45 -0500
Reply-To:     Chemical Propulsion Research <CHEMROC@UGA.CC.UGA.EDU>
Sender:       Chemical Propulsion Research <CHEMROC@UGA.CC.UGA.EDU>
From:         Terry McCreary <terry.mccreary@MURRAYSTATE.EDU>
Subject:      thrust stand works!
Mime-Version: 1.0
Content-Type: text/plain; charset="us-ascii"

Sunday I set up the thrust stand and tested six motors (ca 100 N-s) on it.
All six worked flawlessly (well, one spit the igniter but worked fine on the
second try). Thrust stand worked flawlessly until the last motor, which
maxed out and slightly disassembled the load cell. No real problem, I just
have to replace a stripped screw.
Many thanks to John Horton for providing a very low cost computer for this
work (John, I sent you a pkg today, let me know when you get it).

I'm preparing a web page describing the thrust stand. Total cost for stand,
load cell (to 200 N), data acquisition system, amplifier was about $250.
All new components, no surplus or closeout parts.

Additional notes: These motors were all Bates 3-grain, no exit cone, just a
nozzle throat. The average thrust was determined for each motor, and from
that the average chamber pressure was calculated. Using chamber pressure
and burn rate, values of a and n were determined by plotting log rate vs.
log chamber pressure. Values were: a=0.046, n= 0.187. That's an extremely
low value for the exponent, but it seems to be correct; the propellant
worked from Kn= 280 to Kn=595. And could possibly go lower than 280.

Propellant composition: 77.6% 200 micron AP; 0.2% carbon black, 19.5%
binder mixture (see below); 0.5% PAPI; 1.1% each IPDI and DDI.

The binder mixture was made by mixing 593 g of R45M, 297 g Dioctyl adipate,
49 g castor oil; 10 g Tepanol; 7.6 g triphenylbismuth; and 5 g Fluorad (a
fluorocarbon surfactant; probably not necessary).

Propellant was hand mixed, vacuum processed, hand packed.

This was the first set of tests on the thrust stand. More propellant of
this composition will be prepared this week and tested sometime after final
exams (couple of weeks).

P'rfesser


=========================================================================
Date:         Tue, 20 Apr 1999 12:55:05 -0500
Reply-To:     Chemical Propulsion Research <CHEMROC@UGA.CC.UGA.EDU>
Sender:       Chemical Propulsion Research <CHEMROC@UGA.CC.UGA.EDU>
From:         Terry McCreary <terry.mccreary@MURRAYSTATE.EDU>
Subject:      Re: thrust stand works!
Mime-Version: 1.0
Content-Type: text/plain; charset="us-ascii"

At 12:45 PM 4/20/99 -0400, you wrote:
>Terry,
>Interesting post!
>What was the reason you added carbon black and why in such a low percentage to
>your formula?
>Tom

As an opacifier, just enough to make the grain black and opaque. There's no
burn rate catalyst or metal in this mix, so the propellant would be
semi-translucent. The UV radiation from the flame could penetrate a
significant distance into the propellant, possibly igniting it within. An
opacifier makes the grain opaque so that radiation from the flame is
absorbed very near the surface.

That's the theory, and apparently it was true for some of the old
double-base propellants. I'm not sure how necessary carbon black is in
composite propellant. But I added it anyway to be sure. I'd just as soon
not find out that it WAS necessary...

Incidentally these motors ranged from G58 to G80 in NAR classification.

P'rfesser


=========================================================================
Date:         Sat, 24 Apr 1999 16:10:07 +1000
Reply-To:     Chemical Propulsion Research <CHEMROC@UGA.CC.UGA.EDU>
Sender:       Chemical Propulsion Research <CHEMROC@UGA.CC.UGA.EDU>
From:         "Stephen J. Holden" <rocket@ACEPIA.NET.AU>
Subject:      AN Handling
MIME-Version: 1.0
Content-Type: text/plain; charset=us-ascii
Content-Transfer-Encoding: 7bit

To all,

Just a few words about ammonium nitrate handling. Avoid tools that are
made of brass or copper. I just found out that AN can form a shock
sensitive compound in contact with copper containing materials such as
bronze and brass. I have been using brass as the grinding medium for
years with no problem so far. This is going to change now! Does anyone
know where I can get some griding medium that may be suitable for AN?

Also, avoid dry mixes of finely divided metals of Al, Zn, Cu, Pb, Sb,
Ni, Cd, Ag, Ni, Mg. In the presence of water it may react slowly or
explosively with Al, Fe, Mg, Ti and others.

If you are going to use AN with metallic fuels, then always mix the fuel
into the binder, first, and then add the AN. The binder will separate
the fuel from the AN and prevent adverse reactions.

By the way if anyone has any more informaion about AN reactivity,
experiments that you have done or other insights then please post them.

All the best,
Stephen.


=========================================================================
Date:         Mon, 26 Apr 1999 06:58:56 -0400
Reply-To:     Chemical Propulsion Research <CHEMROC@UGA.CC.UGA.EDU>
Sender:       Chemical Propulsion Research <CHEMROC@UGA.CC.UGA.EDU>
From:         "James E. Lanier" <jelanier@BELLSOUTH.NET>
Subject:      Re: Constant burn area
MIME-Version: 1.0
Content-Type: text/plain; charset="iso-8859-1"
Content-Transfer-Encoding: 7bit

>What is a Bates grain?     I thought I knew, but what I know doesn't jibe with
>the statement above.
>--
>N9VEM


B.A.T.E.S.      Ballistics Test and Evaluation System

The BATES grain is a grain designed for such a system. The example of coned
in ends on a core burner can be made to have more uniform burn area with
time.

Jim

=========================================================================
Date:         Mon, 26 Apr 1999 07:02:07 -0400
Reply-To:     Tony.Midea@moa.net
Sender:       Chemical Propulsion Research <CHEMROC@UGA.CC.UGA.EDU>
From:         Tony Midea <Tony.Midea@MOA.NET>
Organization: Royal Oak Schools
Subject:      Re: Constant burn area
MIME-Version: 1.0
Content-Type: text/plain; charset=us-ascii
Content-Transfer-Encoding: 7bit
James E. Lanier wrote:
>
> >What is a Bates grain? I thought I knew, but what I know doesn't jibe with
> >the statement above.
> >--
> >N9VEM
>
> B.A.T.E.S.   Ballistics Test and Evaluation System
>
> The BATES grain is a grain designed for such a system. The example of coned
> in ends on a core burner can be made to have more uniform burn area with
> time.
>
> Jim

So as I recall, the proper ratio for BATES grains is 1:3:5
port:OD:length
Is this correct for a 'neutral' burn?
Tony

=========================================================================
Date:         Mon, 26 Apr 1999 08:15:20 -0400
Reply-To:     Chemical Propulsion Research <CHEMROC@UGA.CC.UGA.EDU>
Sender:       Chemical Propulsion Research <CHEMROC@UGA.CC.UGA.EDU>
From:         "James E. Lanier" <jelanier@BELLSOUTH.NET>
Subject:      Re: Constant burn area
MIME-Version: 1.0
Content-Type: text/plain; charset="iso-8859-1"
Content-Transfer-Encoding: 7bit

>So as I recall, the proper ratio for BATES grains is 1:3:5
>port:OD:length
>Is this correct for a 'neutral' burn?
>Tony
>

That is one of many. The example you gave has about 17% deviation in burn
area. 1 : 2 : 3.5 gives a deviation of about 7.5%. Both of these examples
start and end the same, but increase burn area in between. Clever geometry
can make grains theoretically perfectly flat or neiutral.


Jim

=========================================================================
Date:         Tue, 27 Apr 1999 13:06:46 -0700
Reply-To:     rocket.science@usa.net
Sender:       Chemical Propulsion Research <CHEMROC@UGA.CC.UGA.EDU>
From:         "Edw Jones, PhD" <rocketnet@CSI.COM>
Organization: Lunaris Memorial Moon Rocket Project
Subject:      Re: Constant burn area
MIME-Version: 1.0
Content-Type: text/plain; charset=us-ascii
Content-Transfer-Encoding: 7bit

David Stoddard wrote:
>
> Edw Jones, PhD writes:
> > These modified star configurations have been used for decades in such
> > motors as those that propel Genie, Terrier, many solid boosters, many
> > modern RATOs/JATOs, *and* for the Tartar and Hawk as dual-propellant,
> > dual-thrust motors (the inner part of the grain is boost phase, then the
> > burn continues to the slower burning sustainer phase).
>
>         This specific topic is something I am very interested in knowing
>            more about. Assuming an AP based formula is used for the boost
>            phase, that type of formula would you use for the slower burning
>            sustainer phase? Are these propellent sections separate stages,
>            or are they actually layered with each other in a single stage?
>
>            Dave Stoddard
>            dgs@us.net

Edw Jones expands his comments:

1)   The sustainer propellants are also exclusively AP-based, as well

2) The specific formulations that I am aware of are simple variations
on the usual HTPB/PBAN composites; unfortunately I have worked most of
my life as a propellant chemist in classified projects, and am unclear
which of these sustainer formulations have been declassified, so am
hesitant to provide [classified, military] formulas.

Hopefully others on this list will be more up-to-date on this, and can
give some info they know to be declassified; when I see what they say, I
will be happy to comment further

3)   They are layered.       The process is done in one of two ways:

           a)   Cast the case-bonded sustainer grain
           b)   Remove the mandrel
           c)   Prepare the inner sustainer grain for bonding to the booster grain
           d)   Insert the booster grain mandrel
           e)   Cast the booster grain, etc

The other mode, sometimes used, but more difficult for small motors
(usually reserved for BIG motors):

           a)   Cast the sustainer propellant, and immediately, while still
'fluid,'
           b)   Insert (press in) the precast, pre-cured booster grain with its
mandrel             still within
           c)   Cure the dual-propellant unit
           d)   Remove the booster mandrel

In a typical dual-thrust motor of this configuration (say the HAWK,
Tartar, Standard, AMRAAM), the booster phase is perhaps 4 to 5 seconds
at maybe 30,000 to 65,000 lbs thrust; the transition to sustain phase is
less than 0.5 sec; the sustain phase is perhaps 20-45 seconds (or more),
at perhaps 2000 to 6000 lbf thrust.

I cannot say with authority, but perhaps dual-propellant, dual-thrust
motors are used on the Patriot, and IIRC, also in the now-defunct
Nike-Zeus AICBM. There must be others too -- who can add to this?

Personally, I have long been curious why "amateur" and sport high-power
rocketeers seem to be "locked into" the separate staging mode of
design. The dual-propellant, dual-thrust mode of design offers *many*
advantages, the foremost being KISS.

Anyone know of others who have done dual-propellant 'amateur' rocketry?

------------------------------------------------------------------
Edward Jones, PhD

rocket.science@usa.net
moon.project@usa.net

"Never let schooling interfere with your education."
Mark Twain
=========================================================================
Date:         Wed, 28 Apr 1999 19:02:26 +1000
Reply-To:     Chemical Propulsion Research <CHEMROC@UGA.CC.UGA.EDU>
Sender:       Chemical Propulsion Research <CHEMROC@UGA.CC.UGA.EDU>
From:         "Stephen J. Holden" <rocket@ACEPIA.NET.AU>
Subject:      Re: BATES Spreadsheet
MIME-Version: 1.0
Content-Type: text/plain; charset=us-ascii
Content-Transfer-Encoding: 7bit

Dennis,
A bates grain is simply a short cylindrical grain with the outer surface
bonded to the wall, and therefore, this surface is "restricted" and can't
burn. The flat ends can either be free to burn "un-restricted" or restricted
by special coatings, such as rubber.
(I am not completely certain what the definition of a bates grain, if their is
one then let me know!).

Volumetric loading is quite an important term when comparing different grain
geometry's. It is defined as:

        volumetric loading VL = propellant volume / chamber volume

It compares how much of the chamber is full of propellant to the chamber's
available space that could be full of propellant. This means that if one can
get a high VL then one has effectively used the available space in the rocket
motor, and therefore,one would expect that one would get a greater total
impulse. There is an optimum value for VL for a given grain geometry and motor
design.

One must combine the burning surface area of the two flat ends of the grain
segment with the surface area contribution of the core. These two burn areas,
combined, can produce almost constant burn area and the thrust will be
approximately constant. You will notice in the spreadsheet that as one
increases the core diameter (d), one can get a more constant burn area for a
given L/D ratio. One can see that at a L/D ratio of approx. 1.75 gives you the
flattest burn area progression for common ranges of (d). Others will be more
progressive or regressive.

The important thing to realize, is, that as the grains core diameter
increases, the lower the VL and hence the lower the total impulse (See Jim's
book as he explains this fore core burning grains). If one is aiming for
larger VL and at the same time constant burn area, then I have a "hunch" (I
think that someone has mentioned this) that tapering the ends of the grain may
yield a better result. But, I need to develop the burn area equation(s) before
I can test this idea. If anyone has done this, then please post the equation.

A bates grain will never produce constant thrust with a restricted outer
surface. It will always have a degree of burn area variation, but it can be
faily close.

Please add to this spreadsheet. There are many useful changes/additions that
can be made to yield useful data and spur new ideas etc........

Have a great day.....Stephen.

Dennis Erwin Thurlow wrote:

>   > I will, when I get the time, add tapered ends to the grain
>   > to see how this effects volumetric loading...
>   > The grain has the outer surface restricted, with both ends free to burn.
>
>   volumetric loading???
>   surface restricted???
>
>   I still can't picture a Bates grain, and "both ends free to burn"
> destroys any ideas I had.
>
> I _do_ see how a cylindrical grain with a cylindrical core running
> its entire length can yield a constant burn surface by tapering
> the ends. A very elegant solution!
> --
> N9VEM
> geosynq@michianatoday.com
http://mem.tcon.net/users/5012/9019/


=========================================================================
Date:         Wed, 28 Apr 1999 11:05:12 -0500
Reply-To:     Chemical Propulsion Research <CHEMROC@UGA.CC.UGA.EDU>
Sender:       Chemical Propulsion Research <CHEMROC@UGA.CC.UGA.EDU>
From:         Terry McCreary <terry.mccreary@MURRAYSTATE.EDU>
Subject:      Re: BATES Spreadsheet
Mime-Version: 1.0
Content-Type: text/plain; charset="us-ascii"

At 10:25 PM 4/27/99 -0400, you wrote:

>I still can't picture a Bates grain, and "both ends free to burn"
>destroys any ideas I had.

Imagine a paper tube of composite propellant a foot long or so, 1" dia, with
a 3/8" core the entire length. Cut the tube into 1.5" long grains. Those
are unrestricted Bates grains. Drop six of them into a casing with nozzle
and forward closure, and you have an H-motor. Even though the propellant
ends touch, they will burn. Oh yes indeedy...

To keep then ends from burning, you could mix a little epoxy to coat the
bare ends. Though if you wanted to do that, it would be just as easy not to
cut the tube into smaller grains...

The restricted grains would burn in the core only, and the burn area
increases during the burn. That's a progressive burn.

If the grains are cut much shorter than 1.5", they'd have maximum surface
area at the beginning, tapering off during the entire burn. That's a
regressive burn.

Aerotech tailors their motors to a certain extent by using eroding phenolic
nozzles and longer-than-usual grains. The grains make for a progressive
burn, but that's balanced somewhat by the nozzle diameter increasing during
the burn. So many of their Bates-grain motors are pretty flat-burning. The
J350 has shorter-than-normal grains; it's pretty regressive.

The modification I was referring to was to machine the ends of each grain to
an "internal taper", i.e., countersink each end. That is supposed to give a
more neutral burn. Never been there, never done that.

One interesting point (well, maybe not...). The motors I tested last week
used three Bates grains each, 0.95" x 1.5" x 3/8" core, graphite nozzle. At
startup there was a little 'hump'. I thought that was erosion but it
occured for each motor, even with a 0.13" nozzle. Hypothesis is that it was
the result of the igniter restricting the nozzle, until said igniter wire
burned through. And the last part of the burn tapered off a fair bit for
each motor.

P'rfesser
=========================================================================

=========================================================================
Date:         Wed, 5 May 1999 00:29:27 -0400
Reply-To:     Chemical Propulsion Research <CHEMROC@UGA.CC.UGA.EDU>
Sender:         Chemical Propulsion Research <CHEMROC@UGA.CC.UGA.EDU>
From:           Robert Rochte <robert@NORDHAUS.COM>
Subject:        Re: PSAN
Comments: cc:   jwckman@trib.com
In-Reply-To:    <372FC118.51305557@hwy97.net>
MIME-Version:   1.0
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Unless you're planning on making and *storing* your motors for long
periods of time -- which then implies that you must also have at least a
federal LEUP (and probably a LEMP) and further, that your magazine is
located at your launch site (since you can't legally transport your
assembled motors without jumping all the DOT hurdles) -- I would question
the need for PSAN to begin with. [Whew -- that was a big sentence...]

If you're looking for volume and price, then why not simply stick with
plain AN? The resulting propellant will be identical to one made with
PSAN, as long as there isn't any significant temperature cycling.

You might even ask Mr Wickman if he can supply garden-variety AN at a
reduced price from his PSAN (which seems a bit pricey, especially once you
add in the handling and HAZMAT fees)....


On Tue, 4 May 1999, Bruce Nolting wrote:

>   Anyone know of any northwest suppliers of phase stabilized ammonium
>   nitrate powder? I already emailed Mr. Wickman and am waiting to hear
>   from him.
>   I will (hopefully) be needing a fairly regular supply so the best price
>   is an issue. Any help would be greatly appreciated.
>
>   Bruce
>

=========================================================================
Date:         Thu, 6 May 1999 21:07:49 -0400
Reply-To:     Chemical Propulsion Research <CHEMROC@UGA.CC.UGA.EDU>
Sender:       Chemical Propulsion Research <CHEMROC@UGA.CC.UGA.EDU>
From:         "James E. Lanier" <jelanier@BELLSOUTH.NET>
Subject:      PSAN...silicon additive
Comments: To: "Chemroc@listserv.uga.edu" <chemroc@listserv.uga.edu>
MIME-Version: 1.0
Content-Type: text/plain; charset="iso-8859-1"
Content-Transfer-Encoding: 7bit

It was I that suggested the use of Silicon in AN formulations. Silicon does
raise the temp and therefore the Isp of AN propellants. The problem is, it
is still hard to ignite. Magnesium reacts with molten AN so it is a thermic
component as well as a catalyst of sorts. I like to use AN and silicon, but
I add some AP to aid in ignition. While doing a patent search, I found that
others have used small amounts of AP in their AN formulations.


"A high performance propellant having greatly reduced hydrogen chloride
emission is disclosed comprising a minor amount of hydrocarbon binder
(10-15%) and at least 85% solids including ammonium nitrate as the primary
oxidizer (about 40% to 70%), a significant amount (5-25%) powdered metal
fuel, such as aluminum, a small amount (5-25%) of ammonium perchlorate as a
supplementary oxidizer and optionally a small amount (0-20%) of a nitramine
such as HMX." US4158583


Jim
=========================================================================
Date:         Fri, 7 May 1999 17:09:26 +1000
Reply-To:     Chemical Propulsion Research <CHEMROC@UGA.CC.UGA.EDU>
Sender:       Chemical Propulsion Research <CHEMROC@UGA.CC.UGA.EDU>
From:         "Stephen J. Holden" <rocket@ACEPIA.NET.AU>
Subject:      Re: PSAN...silicon additive
MIME-Version: 1.0
Content-Type: text/plain; charset=us-ascii
Content-Transfer-Encoding: 7bit

Jim,
It has become apparent to me that most amateur propellants don't need a high
binder content.
Simply adding less binder is the solution to the problem of poor igniterbility
of AN propellants with silicon as the fuel. The small amount of binder can be
distributed through the propellant with an evapourative solvent and compressed
to form the grain and then removal of the solvent by heat. This has become the
idea that I am going to develope for my final year project at University. Thanks
for the suggestion Jim many months ago!....Stephen.

James E. Lanier wrote:

> It was I that suggested the use of Silicon in AN formulations. Silicon does
> raise the temp and therefore the Isp of AN propellants. The problem is, it
> is still hard to ignite. Magnesium reacts with molten AN so it is a thermic
> component as well as a catalyst of sorts. I like to use AN and silicon, but
> I add some AP to aid in ignition. While doing a patent search, I found that
> others have used small amounts of AP in their AN formulations.
>
> "A high performance propellant having greatly reduced hydrogen chloride
> emission is disclosed comprising a minor amount of hydrocarbon binder
> (10-15%) and at least 85% solids including ammonium nitrate as the primary
> oxidizer (about 40% to 70%), a significant amount (5-25%) powdered metal
> fuel, such as aluminum, a small amount (5-25%) of ammonium perchlorate as a
> supplementary oxidizer and optionally a small amount (0-20%) of a nitramine
> such as HMX." US4158583
>
> Jim
>
> >I think that this says it all! As with the propellant that I am developing,
> it was
> >suggested to me to add silicon powder as the fuel. It would be nice if one
> could try
> >this with the CP Technologies propellant. You will get a lower Isp, but the
> silicon
> >powder is allot safer then Mg and is quite cheap by comparison. Silicon can
> be
> >purchased from FireFox for $4.50/lb (not including postage). Does anyone
> know what
> >particle size this is! Another advantage with this is the fact that silicon
> does not
> >react with AN when wet with water like Mg...Have fun....Stephen
=========================================================================
Date:         Fri, 7 May 1999 08:08:40 -0400
Reply-To:     Chemical Propulsion Research <CHEMROC@UGA.CC.UGA.EDU>
Sender:       Chemical Propulsion Research <CHEMROC@UGA.CC.UGA.EDU>
From:         "James E. Lanier" <jelanier@BELLSOUTH.NET>
Subject:      Re: AN..Silicon, Binders ,Additives
MIME-Version: 1.0
Content-Type: text/plain; charset="iso-8859-1"
Content-Transfer-Encoding: 7bit

That reminds me..if AN is ground too finely, it becomes very difficult to
mix with a binder. In fact, it may not even seem like it has been "wetted".
The mix is then compressed into a grain and allowed to cure. The only
problem is that the grain has the consistency of igneous rock
(exaggeration). While this is fine in some cases, the lack of elasticity can
result in a grain split under pressure in other cases. The solvents you
refer to can aid in the mixing process, but the rock hard grain does have
limitations. This is most likely a problem on larger motors. But, as Stephen
says, it may work fine in some amateur applications.

Jim


=========================================================================
Date:         Sat, 8 May 1999 11:10:10 +1000
Reply-To:     Chemical Propulsion Research <CHEMROC@UGA.CC.UGA.EDU>
Sender:       Chemical Propulsion Research <CHEMROC@UGA.CC.UGA.EDU>
From:         "Stephen J. Holden" <rocket@ACEPIA.NET.AU>
Subject:      Re: AN..Silicon, Binders ,Additives
MIME-Version: 1.0
Content-Type: text/plain; charset=us-ascii
Content-Transfer-Encoding: 7bit

If the solvent is alcohol then the this wetting problem does not seem to be a
problem. If one uses a Bates grain with cartridges that slide into the motor,
then essentially the grain is only in compression from the pressure load. Their
is no significant radial load that would accrue if the grain was case bonded.
The grain produced by the method that I am going to use is high in compressive
strength but low in tensile strength. The acceleration loading may be a problem
then.
The elasticity of the grain will be poor, but, since we are using a Bates grain,
I don't think that this is a great problem. Each grain is therefore short in
length and thus the elasticity needed is not as important. For a cylindrical
grain (a long grain) then this is more important......All the best, Stephen.


=========================================================================
Date:         Mon, 10 May 1999 00:16:41 -0400
Reply-To:     Chemical Propulsion Research <CHEMROC@UGA.CC.UGA.EDU>
Sender:       Chemical Propulsion Research <CHEMROC@UGA.CC.UGA.EDU>
From:         Americo Borza <aborza@NETZERO.NET>
Subject:      Re: silicon
MIME-Version: 1.0
Content-Type: multipart/alternative;
              boundary="------------15EDAF24163D0AEC4DD64187"

--------------15EDAF24163D0AEC4DD64187
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Hello Stephen,

You will find what you want from AEE. Less than 5 micron pure silicone at about $17
per pound if you buy about three pounds. It is shipped as a non hazardous non
flammable material in a one quart steel paint type can. This is exactly the stuff
referred to in the Patent data I sent you and that I posted to the ARocket list a
few months age. It is the stuff having the lowest signature.

Here is the URL:

 AEE - AEE Home Page http://www.micronmetals.com/index5.htm

Let me know what comes out of your work.

ab

=========================================================================
Date:         Sun, 16 May 1999 15:36:09 -0400
Reply-To:     Chemical Propulsion Research <CHEMROC@UGA.CC.UGA.EDU>
Sender:       Chemical Propulsion Research <CHEMROC@UGA.CC.UGA.EDU>
From:         Dennis Erwin Thurlow <geosynq@MICHIANATODAY.COM>
Subject:      Pc question
Comments: To: Chemroc - Lanier <chemroc@listserv.uga.edu>
MIME-Version: 1.0
Content-Type: text/plain; charset=us-ascii
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This formula has been given in about half a dozen posts is:

Pc=(c*)(propellant density)(Burn Rate)(Kn)

In one post someone stated that gravity had to be included, and posted:

Pc=(c*)(propellant density)(Burn Rate)(Kn)(g)

For the units to work, you actually need to divide by g!?!
But in subsiquent posts, I don't see either being done.
The difference is significant. Which is correct?
--
N9VEM
geosynq@michianatoday.com
http://mem.tcon.net/users/5012/9019/
=========================================================================
Date:         Sun, 16 May 1999 17:51:57 -0400
Reply-To:     Chemical Propulsion Research <CHEMROC@UGA.CC.UGA.EDU>
Sender:       Chemical Propulsion Research <CHEMROC@UGA.CC.UGA.EDU>
From:         Robert Rochte <robert@NORDHAUS.COM>
Subject:      Re: Pc question
In-Reply-To: <373F1E29.6EDF@michianatoday.com>
MIME-Version: 1.0
Content-Type: TEXT/PLAIN; charset=US-ASCII

It depends on whether you're using SI units (in which case density is
expressed using *mass*) or English units (in which case density is
expressed using *weight*). With English units, you essentially need to
convert weight (pounds) into mass (slugs), which is done by dividing by g.

That's my understanding, anyway, and it seems to work.


=========================================================================
Date:         Mon, 17 May 1999 12:20:34 -0400
Reply-To:     Chemical Propulsion Research <CHEMROC@UGA.CC.UGA.EDU>
Sender:       Chemical Propulsion Research <CHEMROC@UGA.CC.UGA.EDU>
From:         "James E. Lanier" <jelanier@BELLSOUTH.NET>
Subject:      Re: Pc question
Comments: To: "Chemroc@listserv.uga.edu" <chemroc@listserv.uga.edu>
MIME-Version: 1.0
Content-Type: text/plain; charset="iso-8859-1"
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Pc=(c*)(propellant density)(Burn Rate)(Kn)

where c*= characteristic exhaust velocity
Kn= Burn area divided by throat area (or Ab/At)
Burn Rate may also be represented by r, or recession rate

Example:

c*=4000 ft/sec
density=.06 lbm per cubic inch
Burn Rate=.3 inches per second
Kn=150

Pc=4000*(.06/32.2)(.3)(150)=335.4 psi
These terms and this formula are derived in my book in easy to understand
terms. A more usable model is also derived and is the basis for simple
computer models.

Jim

=========================================================================
Date:         Thu, 20 May 1999 23:15:45 -0400
Reply-To:     Chemical Propulsion Research <CHEMROC@UGA.CC.UGA.EDU>
Sender:       Chemical Propulsion Research <CHEMROC@UGA.CC.UGA.EDU>
From:         Robert Rochte <robert@NORDHAUS.COM>
Subject:      KNO3/Mg/Epoxy propellant
Comments: To: arocket@nmt.edu
MIME-Version: 1.0
Content-Type: TEXT/PLAIN; charset=US-ASCII

I had a few spare minutes tonight and, while considering the never-ending
quest for a good "introductory" propellant for experimentalists, decided
to whip up a very small batch of 60% KNO3/20% Mg/20% Epoxy binder.

To my surprise, the tiny cured block of propellant burned even more
vigorously than the Oberth/CP Technologies AN propellant from which I
borrowed the idea.

Knowing that KNO3 is fairly easy to come by in most parts of the world
(without the bomb-making hysterics caused by someone asking for AN/AP/KP),
I was wondering if this wouldn't be a good alternative to cooking up Candy
propellant for the beginner. Obviously, one still needs a source of Mg
(my test batch used 600mic atomized Mg from Firefox) -- and the Mg raises
the price of the propellant significantly -- but this should be quite a
bit easier than finding a ready supply of AN/AP/KP.

Any thoughts or comments on this combination? I didn't try it with HTPB
(since the goal is to use only readily available components -- and I
didn't want to wait for the cure!), but I imagine it would work even
better and certainly provide a more CATO-proof grain. Any estimates of
"a" and "n", if someone has already tried this?? (At least the STP
burnrate appears to be faster than the same thing with AN.)
=========================================================================
Date:         Thu, 20 May 1999 23:57:45 -0400
Reply-To:     Chemical Propulsion Research <CHEMROC@UGA.CC.UGA.EDU>
Sender:       Chemical Propulsion Research <CHEMROC@UGA.CC.UGA.EDU>
From:         Robert Rochte <robert@NORDHAUS.COM>
Subject:      correction
Comments: To: arocket@nmt.edu
MIME-Version: 1.0
Content-Type: TEXT/PLAIN; charset=US-ASCII

My post about KNO3/Mg/Epoxy referred to "600mic" Mg -- as most here
probably realized, this should have said "600 mesh".

=========================================================================
Date:         Wed, 26 May 1999 17:07:49 -0400
Reply-To:     Chemical Propulsion Research <CHEMROC@UGA.CC.UGA.EDU>
Sender:       Chemical Propulsion Research <CHEMROC@UGA.CC.UGA.EDU>
From:         Dennis Erwin Thurlow <geosynq@MICHIANATODAY.COM>
Subject:      plasticizers
Comments: To: Chemroc - Lanier <chemroc@listserv.uga.edu>
MIME-Version: 1.0
Content-Type: text/plain; charset=us-ascii
Content-Transfer-Encoding: 7bit

I know the structure of Dioctyl Adipate, also called bi(2-ethyl hexyl) adipate
and several other names, but cannot find a definition for adipate, or the
mechanism by which it works. Can anyone give the 2 cent synopsis?
While looking, I came across several references to "epoxiated vegetable oils"
as a substitute for petroleum based plasticizers. It brought two things to
mind. 1.) Rich's comment about linseed oil polymerizing, and 2.) this formula:
77.6% 200 micron AP; 0.2% carbon black, 19.5% binder mixture; 0.5% PAPI;
1.1% each IPDI and DDI. Binder mixture - 593 g R45M, 297 g DOA, 49 g castor oil;
10 g Tepanol; 7.6 g triphenylbismuth; and 5 g Fluorad surfactant.

I've been trying to use polyester resin, cured with peroxide, for composite
motors, and have not had much luck. I believe it sets too hard to burn fast.
I want to try adding a plasticizer, and would love to try an epoxiated vegetable
oil, but I don't have a clue re: how one might do that. I'm guessing the
tepenol and triphenylbismuth do it for caster oil in the formula above, but that
doesn't help me much as I'd also have to make the triphenyl bismuth.
Anyone know a home lab method of epoxiating an oil?

BTW, I also stumbled across a guy at Goddard who metal plates epoxy.
I asked for more info.
--

=========================================================================
Date:         Fri, 28 May 1999 08:27:34 -0400
Reply-To:     Chemical Propulsion Research <CHEMROC@UGA.CC.UGA.EDU>
Sender:       Chemical Propulsion Research <CHEMROC@UGA.CC.UGA.EDU>
From:         "James E. Lanier" <jelanier@BELLSOUTH.NET>
Subject:      Binder for AN...(energetic)
Comments: To: "Chemroc@listserv.uga.edu" <chemroc@listserv.uga.edu>
MIME-Version: 1.0
Content-Type: text/plain; charset="iso-8859-1"
Content-Transfer-Encoding: 7bit

    I was thinking about Mr. Holden's AN propellant development and thought
I would put in my 2 cents worth. I tried an experiment that seems promising.
I took about 25% nitrocellulose (dry) and added it to a dry AN
formulation(75%) and mixed. I then added a small amount of acetone to solve
the nitrocellulose. After mixing thoroughly, I placed it in a mold and let
it dry. It burns very well at atmospheric pressure. This seems to be
preferable to a binder made up of shellac since nitro is energetic in
itself. The only thing is..I don't know what "n" will be. It may be high so
be careful!!!!
    It is conceivable that a small amount of oil could be added for some
degree of elasticity. I will leave that up to the experimenter. (FYI: some
ping pong balls are made of nitrocellulose) When purchasing NC in the
US...it is packaged with a small amount of graphite to "short out" static
charges that may cause unwanted ignition. I don't think the amount of
graphite is significant.

Jim


=========================================================================
Date:         Fri, 28 May 1999 15:58:22 -0500
Reply-To:     Chemical Propulsion Research <CHEMROC@UGA.CC.UGA.EDU>
Sender:       Chemical Propulsion Research <CHEMROC@UGA.CC.UGA.EDU>
From:         garym <garym@IPA.NET>
Subject:      Re: Binder for AN...(energetic)
MIME-Version: 1.0
Content-Type: text/plain; charset=us-ascii
Content-Transfer-Encoding: 7bit

use 10% Nitocellulose laquer instead available at hobby shops, Sig brand.

"James E. Lanier" wrote:

>     I was thinking about Mr. Holden's AN propellant development and thought
> I would put in my 2 cents worth. I tried an experiment that seems promising.
> I took about 25% nitrocellulose (dry) and added it to a dry AN
>   formulation(75%) and mixed. I then added a small amount of acetone to solve
>   the nitrocellulose. After mixing thoroughly, I placed it in a mold and let
>   it dry. It burns very well at atmospheric pressure. This seems to be
>   preferable to a binder made up of shellac since nitro is energetic in
>   itself. The only thing is..I don't know what "n" will be. It may be high so
>   be careful!!!!
>       It is conceivable that a small amount of oil could be added for some
>   degree of elasticity. I will leave that up to the experimenter. (FYI: some
>   ping pong balls are made of nitrocellulose) When purchasing NC in the
>   US...it is packaged with a small amount of graphite to "short out" static
>   charges that may cause unwanted ignition. I don't think the amount of
>   graphite is significant.
>
>   Jim


=========================================================================
Date:         Sat, 29 May 1999 12:15:55 +1000
Reply-To:     Chemical Propulsion Research <CHEMROC@UGA.CC.UGA.EDU>
Sender:       Chemical Propulsion Research <CHEMROC@UGA.CC.UGA.EDU>
From:         "Stephen J. Holden" <rocket@ACEPIA.NET.AU>
Subject:      Re: Binder for AN...(energetic)
MIME-Version: 1.0
Content-Type: text/plain; charset=us-ascii
Content-Transfer-Encoding: 7bit

Jim,      garym and all,

This is the approach taken when using silicon powder in AN propellants, namely
adding an energetic binder to compensate for the compositions lower Isp and poor
burning using less energetic binders.

The only problem is that one is adding materials that are quite unstable and as
such,
will reduce the safety aspects of the composition. I have managed to get a frozen
specific impulse up to 243 seconds using small amounts of shellac and silicon
powder and carbon as the fuels. To me this is higher enough and will do, as I want
a composition that I can be confident that the mixture is very safe to handle
(comparatively to other propellants, please don't send me lots of E-mails telling
me that their is no such thing as a safe propellant, don't worry I know!) It seems
to me that their is allot of merit is designing propellants to have safe handling
properties for amateur rocketry, anyway!

The mechanical properties of this propellant may or may not be a problem in small
rockets; this is something that we are going to test quite thoroughly to see.

It will boost the Isp to almost that of AP propellants. The value of n will most
certainly be very high. To prevent this you will need to compress the propellant
and use less than 7 % solvent in the propellant to reduce the voids and hence,
lower n. This makes it a bit tricky, but if you can come up with a workable method
then this is a nice approach.

My project at Swinburne almost did to come through due to safety concerns. We had
to change the project quite a bit. We are going to use strand burning rather than
a BEM and concentrate mainly on the characterization of the propellant. The only
problem is that it is very difficult to form a compressed propellant into strands!
Because we are using alcohol as the solvent, to compress small strands would take
too long, since by the time we have compressed one or two, the solvent will have
evaporated too much and affect our results!

One method that may work is to compress the propellant into a flat sheet and then
saw it into strands. The sheet will need to be supported to prevent breaking the
strand.
We are going to start the project in 3 weeks.

Just as an aside has anyone tried to nitrate, shellac. It may form a worthwhile
binder that is energetic. Also, I have heard that shellac can be rubberized, I not
certain if this is true or not.

If we can add sufficient shellac to the propellant (we will see how much is the
maximum before it affects burning significantly, probably about 8%) then perhaps
other more flexible binders may work and this would improve fracture toughness.
Perhaps a plasticizer could be added?

Have a great day....Stephen.

garym wrote:

>   use 10% Nitocellulose laquer instead available at hobby shops, Sig brand.
>
>   "James E. Lanier" wrote:
>
>   >       I was thinking about Mr. Holden's AN propellant development and thought
>   >   I would put in my 2 cents worth. I tried an experiment that seems promising.
>   >   I took about 25% nitrocellulose (dry) and added it to a dry AN
>   >   formulation(75%) and mixed. I then added a small amount of acetone to solve
>   >   the nitrocellulose. After mixing


=========================================================================
Date:         Sun, 30 May 1999 23:49:28 +1000
Reply-To:     Chemical Propulsion Research <CHEMROC@UGA.CC.UGA.EDU>
Sender:       Chemical Propulsion Research <CHEMROC@UGA.CC.UGA.EDU>
From:         "Stephen J. Holden" <rocket@ACEPIA.NET.AU>
Subject:      Re: Binder for AN...(energetic)
MIME-Version: 1.0
Content-Type: text/plain; charset=us-ascii
Content-Transfer-Encoding: 7bit

Correction should be:
83% AN
12% Si
3% C
Shellac Binder, add about 8% of (80% Ethyl Alcohol: 20% Orange Shellac): 92% Propellant.


=========================================================================
Date:         Sun, 30 May 1999 20:15:24 +0200
Reply-To:     "Javier D." <javier.d@teleline.es>
Sender:       Chemical Propulsion Research <CHEMROC@UGA.CC.UGA.EDU>
From:         "Javier D." <javier.d@TELELINE.ES>
Subject:      Re: KNO3/Mg/Epoxy propellant
MIME-Version: 1.0
Content-Type: text/plain; charset="iso-8859-1"
Content-Transfer-Encoding: 7bit

Hello Robert,

What is about your KNO3 composite ?

I has try with a different mixtures without luck, I am very interested in
your advances.

I has try with :

KNO3+HTPB = burn very bad and a lot a chuff
KNO3+ EPOXY = the best result  but with chuff

KNO3 + AL + EPOXY = CHUFF      and AL without burn

My theory is KNO3 need Mg 14 mic or less and to use Al need 5-10 mic. AN
composites use a 4% Mg and 8% AL with 4% Poassium dichromate to Catalizer,
But I don't know why Plastic binder generate chuff.

Now I use 1600g ,   65% KNO3 35% Sorbitol in my motors.

Javier D.
www.teleline.es/personal/titanium

=========================================================================
Date:         Mon, 31 May 1999 11:39:05 +1000
Reply-To:     Chemical Propulsion Research <CHEMROC@UGA.CC.UGA.EDU>
Sender:       Chemical Propulsion Research <CHEMROC@UGA.CC.UGA.EDU>
From:         "Stephen J. Holden" <rocket@ACEPIA.NET.AU>
Subject:      Re: KNO3/Mg/Epoxy propellant
MIME-Version: 1.0
Content-Type: text/plain; charset=us-ascii
Content-Transfer-Encoding: 7bit

Robert, Javier,,,
I have noticed the unstable combustion of KNO3 with Al and resins. It seems
that unstable combustion is quite prevalent when working with mixtures that
don't burn
well at atmospheric pressure. It may have something to do with inefficient
combustion at the propellant grains surface. The large amount of solid
components in the exhaust may disrupt the burning at the surface.

I think that your idea is workable if you just add a small amount of Mg and no
Al. You need a very energetic material to help the combustion such as Mg.
Also, don't add too much as this might cause the chuffing. Slowly increase the
amount of Mg and see if this has a effect on the chuffing. I would try all of
this before adding the catalyst to see if the catalyst makes a difference or
not....Stephen.


=========================================================================
Date:         Sun, 30 May 1999 19:36:07 -0700
Reply-To:     rocket.science@usa.net
Sender:       Chemical Propulsion Research <CHEMROC@UGA.CC.UGA.EDU>
From:         "Edw Jones, PhD" <rocketnet@CSI.COM>
Organization: Lunaris Memorial Moon Rocket Project
Subject:      Propellant Chemicals reference sheets?
Comments: To: "arocket@nmt.edu" <arocket@nmt.edu>,
          Lunaris Moon Teams! <moonproject@nmt.edu>
MIME-Version: 1.0
Content-Type: text/plain; charset=us-ascii
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It seems to me that with the frequent and in-depth discussions here
about propellant chemicals it would be useful and worthwhile to create
and publish, in the public domain, a set of "Propellant Chemicals
Reference Sheets."

Each Sheet would refer to a single propellant chemical, and have an
easy-to-use table that gives the essential reference data (physical and
chemical properties) for that chemical.

Each sheet would also contain a table of storage and handling hazards (a
distillate of the MSDSs).

Further, each sheet would have a table that shows the typical parameters
employed with that chemical in propulsion applications (for instance,
Isp versus various complimentary oxidizers/fuels, as appropriate).

Primary manufacturers and distributors can also be listed, along with
industrial (non-propellant) uses and applications for each chemical.

I'm ready to take on this little Reference Sheets project, but would
first like to have any and all feedback from these lists about their
potential utility. I'm interested to find out if we generally would
find them useful (probably e-published, in some versatile format(s)).

Second, it would be nice to have a list of individuals who are willing
to proof-read and/or facts-check each page before considering it final.
Are you willing to share a little data and/or help with this?

Finally, I want to compile a basic list of most important propellant
chemicals before attempting to expand or make the Reference Sheets broad
and expansive. At this point I would like to create Reference Sheets
for these few propellant chemicals:

Ammonium perchlorate
Ammonium nitrate
Potassium nitrate
PBAN
HTPB
Sugars [maybe a better generic name is possible for this group]
Hydrogen peroxide
Liquid oxygen
Nitrous oxide
White fuming nitric acid (and IWFNA)
Kerosenes (including RPs and JPs)
Gasolines
Furfuryl alcohol
Unsymmetrical dimethyl hydrazine (UDMH)

Are there other *basic and essential* chemicals missing from this
*Basic* List?

Any comments, suggestions, advice, or assistance will be much
appreciated.



Edward Jones

rocket.science@usa.net

=========================================================================
Date:         Mon, 31 May 1999 17:12:02 +0200
Reply-To:     Chemical Propulsion Research <CHEMROC@UGA.CC.UGA.EDU>
Sender:       Chemical Propulsion Research <CHEMROC@UGA.CC.UGA.EDU>
From:         LudwigS <h0444pcd@STUDENT.HU-BERLIN.DE>
Subject:      Re: KNO3/Mg/Epoxy propellant
In-Reply-To: <3751E838.7D3DDDB7@acepia.net.au>
Mime-Version: 1.0
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Hello folks!

At 11:39 31.05.99 +1000, Stephen J. Holden wrote:
>Robert, Javier,,,
>I have noticed the unstable combustion of KNO3 with Al and resins. It seems
>that unstable combustion is quite prevalent when working with mixtures that
>don't burn
>well at atmospheric pressure.
_Does_ a composition of KNO3 and Epoxy combust fast and stable at higher
pressures,
i.e. enough to make it a suitable propellant? What I've noticed so far,
after some
experiments, is that a comp. of 70% KNO3 and 30% Epoxy does burn very
smokey and
not very fast. When decreasing the amount of KNO3 to 55% it evens starts to
burn
in an oscillating manner, it strobes at a frequency of about 1Hz. It also
leaves
quite a lot of dark substance due to the fact that this mix is heavily
overfueled.

>It may have something to do with inefficient
>combustion at the propellant grains surface. The large amount of solid
>components in the exhaust may disrupt the burning at the surface.
So it(the 'solid components')would d be carried away under bigger pressure
and thus causing an increase of the burn rate? Can anyone confirm whether
this is true, concerning our KNO3 Epoxy comp.? I suppose further efforts to
make this work are justified, the outcome would be a cheap, 'quick and dirty'
composite motor. The problem is, i don't see that epoxy is a good fuel in
combination
with rather less active oxidizers like KNO3. Even a 60%KClO3 - 40% epoxy
mixture
took ages to burn completly in an unconfined configuration. I see this was
somewhat
overfueled too, but i expected it to burn a bit faster though...

>I think that your idea is workable if you just add a small amount of Mg
and no
>Al. You need a very energetic material to help the combustion such as Mg.
Well, that might be a solution.
What ratio of KNO3:Epoxy is considered to be the optimum?

Ludwig.
--1st Post to this group, huha! ;)
=========================================================================
Date:         Mon, 31 May 1999 17:57:41 +0200
Reply-To:     "Javier D." <javier.d@teleline.es>
Sender:       Chemical Propulsion Research <CHEMROC@UGA.CC.UGA.EDU>
From:         "Javier D." <javier.d@TELELINE.ES>
Subject:      Re: KNO3/Mg/Epoxy propellant
MIME-Version: 1.0
Content-Type: text/plain; charset="iso-8859-1"
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Hello,

I think that the problems is the very low temperature obtain with KNO3 in
comparataionn with AP, PP or AN
and if you use a 8 % or more of Mg you can burn with 1871 C in the motor
chamber (Propep program ).
My experiment with AL 400mesh no burn, AN mixtures use 4%mg 325mesh and 8%
Al   "2 mic", is posibleee with KN mixtures use a 2 mic AL burn well but
expensive.

Or change the Epoxy with Poliester burn with less temperature.

Ideas ?

Javier D.


KCLO3 is a sensitive to preasure, with organic plastic you obtain a good
explosive .



=========================================================================
Date:         Mon, 31 May 1999 11:23:31 -0400
Reply-To:     Chemical Propulsion Research <CHEMROC@UGA.CC.UGA.EDU>
Sender:       Chemical Propulsion Research <CHEMROC@UGA.CC.UGA.EDU>
From:         Robert Rochte <robert@NORDHAUS.COM>
Subject:      Re: KNO3/Mg/Epoxy propellant
In-Reply-To: <3.0.6.32.19990531171202.007cf860@popserv.rz.hu-berlin.de>
MIME-Version: 1.0
Content-Type: TEXT/PLAIN; charset=US-ASCII

There are two ways I've gotten this stuff to work (and I haven't done much
more than a few small motor tests -- I moved to AP-based propellants right
after):

1. Add sucrose to increase the burn rate.   Even then, it's much slower
than just KNO3/sucrose.

2. Add Mg. This burned very well, at the proportions noted in my original
email (which started this thread): 60% KNO3/20% Mg/20% Epoxy. Less epoxy
and it goes *boom* under pressure.

The latter method is based on CP Technologies AN propellant. The burn
rate is a bit slower, but not much. My experiments used 600 mesh Mg from
Firefox.


=========================================================================
Date:         Mon, 31 May 1999 22:47:44 +0200
Reply-To:     "Javier D." <javier.d@teleline.es>
Sender:       Chemical Propulsion Research <CHEMROC@LISTSERV.UGA.EDU>
From:         "Javier D." <javier.d@TELELINE.ES>
Subject:      Re: ref: KNO3/Mg/Epoxy
Comments: To: Chemical Propulsion Research <CHEMROC@UGA.CC.UGA.EDU>
MIME-Version: 1.0
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Hello,

Everybody know that the best Oxidiser is AP, but everybody know that AP is
expensive, is very "danger" (pressure sensitive, low point ignite, is
explosive by itself, and generate HCL), and IS VERY DIFFICULT TO FIND ).

I know that KNO3+(sucrose,dextrose,sorbitol) or BP is enough for rocket
amateur. TUNE GROUP are making a 133 mm O.D. KN+Sorbitol with SRB .

Why I and other person look for a resin binder with KN, because all mixtures
with sugars are hygroscope and with resin binder you can reduce the binder
to 20% or less and you can add metallic fuel, now you can obtain a ISP=170
and no hygroscope mixture and inexpensive.

Javier D.


========================================================================
Date:         Mon, 31 May 1999 22:06:05 -0400
Reply-To:     Chemical Propulsion Research <CHEMROC@LISTSERV.UGA.EDU>
Sender:       Chemical Propulsion Research <CHEMROC@LISTSERV.UGA.EDU>
From:         "James E. Lanier" <jelanier@BELLSOUTH.NET>
Subject:      Re: Binder for AN...(energetic)
MIME-Version: 1.0
Content-Type: text/plain; charset="iso-8859-1"
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-----Original Message-----
From: Edw Jones, PhD <rocketnet@CSI.COM>
To: CHEMROC@UGA.CC.UGA.EDU <CHEMROC@UGA.CC.UGA.EDU>
Date: Sunday, May 30, 1999 2:07 AM
Subject: Re: Binder for AN...(energetic)


>What is meant by the term "frozen Isp"?
>
>Edward


Frozen equilibrium calculations are based on exhaust gas that does not
change in state throughout the nozzle. That is...no chemical reactions or
phase changes. This may be a departure from reality...but certainly easier
to model.

Jim

=========================================================================
Date:         Tue, 1 Jun 1999 21:58:39 -0400
Reply-To:     Chemical Propulsion Research <CHEMROC@LISTSERV.UGA.EDU>
Sender:       Chemical Propulsion Research <CHEMROC@LISTSERV.UGA.EDU>
From:         DarkWing <darkwing7@NAC.NET>
Subject:      Re: ref: KNO3/Mg/Epoxy
MIME-Version: 1.0
Content-Type: text/plain; charset=ISO-8859-1
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>
>      If any of you get something that even remotely approaches AP....I
would
>      love to know about it. I always though alchemy was a more rational
pursuit
>      than getting KNO3 to perform......hmmmm mercury may be the key.....If
we
>      handle it enough, we could lose our minds and think it works as well
as AP.
>
> A low-temp castable propellant based on KNO3 would be valuable in some
> sense even if its performance was only comparable to black powder -
> you're getting into a different class of "manufacturing." Since
> KNO3/Sugar is already know to have better Isp than BP, this doesn't seem
> completely unlikely, either. If you gain 50% over BP by more careful
> choice of chemicals, and then lose 40% to make it castable... I wouldn't
> mind playing with that.
>
> BillW
......ok......that would be useful.......but:

What gets to me is the naive assumption that no one has expended any
serious effort on KN03. About 37 years ago about 100 of us believed we
invented "rocket candy"....fact is, it was fairly self-evident. From that
point,many of us did not like the evil "melting" process ( including my
mom....didn't need the damn garage anyway). However, the pursuit for a
castable version began. Epoxies, PVC, etc. were around and we tried
everything.....Bottom line..nothing really worked unless we "loaded it up
with fine mesh Mg @ percentages as high as 23%. Now we're back to danger
and high cost. After endless efforts....enter PP, AN......and......AP!!!!!
Well, AP was so superior to anything else, it was rightfully embraced. Now
(almost 4 decades later) the circle is complete and we're back to talking
about KNO3/sugar. My earlier post was honest. If anyone comes up with
something "NEW" that performs, I would LOVE to hear about it.....I just
doubt it will happen. I'm not "trashing KNO3...I'm just saying: sometimes
ya got to move on.....after the discovery of electricity and the electric
light bulb, experimenting with new types of whale oil was a questionaple
effort. Lets try to find a better oxidizer, not something that "barely"
works.

=========================================================================
Date:         Sat, 3 Jul 1999 18:46:50 -0700
Reply-To:     Chemical Propulsion Research <CHEMROC@LISTSERV.UGA.EDU>
Sender:       Chemical Propulsion Research <CHEMROC@LISTSERV.UGA.EDU>
From:         Ron Zeppin <zipper@EXTREMEZONE.COM>
Subject:      Re: chemical formula for gunpowder reaction
MIME-Version: 1.0
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Hi All....I'm new here. I've been reading this group for past week, and
finally saw a topic I knew a little about...Here' my 2 cents worth...

If you are interested in building Ammonium Perchlorate based rocket
motors, I'd suggest trying the book/kit that is produced by
Firefox Enterprises Inc.
PO Box 5366
Pocatello, ID 83202
(208) 237-1976

A friend and I have utilized this book, and have built several motors so
far. The last was a modified recipe from the book. It was installed in a
7 pound rocket, 4" diameter, and 7 feet tall...Launch weight was 13
pounds. After recovery, onboard electronics reported the following:

Accelleration: 30G's
Altitude 9244 Feet
Max Velocity: 922mph

The recorded data showed the vehicle passing through Mach at 1.45
seconds. A relatively loud bang was heard as if went through Mach.
Total burn time of the motor was 1.86 seconds, and according to our
calculations, Maximum thrust was 443 pounds @ 1.2 seconds. Total Impulse
worked out to 2659 Newton/Seconds.

Needless to say, we were pretty happy. This was an HTPB motor, and the
grains stayed slightly soft. The grain diameter was 1.8 inches, and the
motor contained 4-6" grains. We are going to reformulate to make it
harder, and attempt to cast 4" diameter grains for a 13,000
Newton/Second motor to be flown at Black Rock in September.
--
Ron Zeppin
TRA# 6024 L2
AHPRA
XRAA

=========================================================================
Date:         Sun, 4 Jul 1999 07:51:41 -0700
Reply-To:     Chemical Propulsion Research <CHEMROC@LISTSERV.UGA.EDU>
Sender:       Chemical Propulsion Research <CHEMROC@LISTSERV.UGA.EDU>
From:         Ron Zeppin <zipper@EXTREMEZONE.COM>
Subject:      Re: 7 foot tall rocket
MIME-Version: 1.0
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Jamie Morken wrote:
>
> Hi all,
>
> That book from Firefox sounds interesting Ron. And the 7 foot tall rocket sounds
> awesome! I am coincidentally making a 7 foot tall rocket, and the fins, nose and body
> are all complete (all fiberglass - aluminum mesh reinforcement in the fins). I am trying
> to make a parachute deployment system for the rocket right now. Any ideas? Thanks
for
> your time,
>
> Jamie Morken


Jamie, I'd like to build a Fiberglass rocket, but at the moment, the
cost is prohibitive. 4" tubing is about 16 bucks a foot! The Rocket I
flew is made from Spiral wound cardboard tubing from LOC Precision, and
is reinforced with Phenolic coupler tubing from Red Arrow Hobbies. The
Fins are 1/8 inch G-10 Fiberglass.

As far as deployment, I'd definitely recommend an altimeter. There are
several manufacturers out there. They range anywhere from about 90 bucks
up to about 240 bucks. A company called Missile Works has a nice one
out. I believe it's about $90.00. Has user selectable main deployment
altitude, a Mach inhibit timer, (So the recovery system does not deploy
when the vehicle goes through Mach...Not a pretty sight...Spectacular,
but not pretty!!) You can check it out at: www.missileworks.com

If you're looking for something at the upper end of the spectrum that
will give you a ton of info, check out www.emmanuelavionics.com

If you want something between these two, let me know, and I'll pull
together all of the companies that I know of that make altimeters, and
post their info here.

See ya!

Ron Zeppin

=========================================================================
Date:         Mon, 5 Jul 1999 13:19:40 -0700
Reply-To:     Chemical Propulsion Research <CHEMROC@LISTSERV.UGA.EDU>
Sender:       Chemical Propulsion Research <CHEMROC@LISTSERV.UGA.EDU>
From:         Ron Zeppin <zipper@EXTREMEZONE.COM>
Subject:      Re: chemical formula for gunpowder reaction
MIME-Version: 1.0
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Bennett Benson wrote:
>
> Nice job Ron! An excellent report. Keep us informed as to your progress. If
> you wouldn't mind, please expand on your modifications to the original
> recipe.
>
> -bennett
>

Hi Bennett/all

The following is the Recipe for a relatively fast burning Ammonium
Perchlorate based HTPB bonded propellant

200 Micron AP                   66%     Oxidizer
90 Micron AP                    08%     Oxidizer
Aluminum -325 Mesh              04%     Increase Combustion Temp
Copper Oxide                    01%     Burn Rate Accellerator
R-45M                           11%     Resin
EHA                             06%     Plasticizer
HX-878 (Tepanol)               .75%     Bonding Agent
Castor Oil                     .50%     Chainlinking Agent
Lecithin                       .75%     Reduces Viscosity
143L                            02%     Curing Agent

Everything but the 143L can be mixed at once.
DO NOT MIX THE ALUMINUM WITH THE RAW AP!!! Mix in the aluminum with the
liquids, and then mix in the other solids. We mixed for 5 minutes,
scraped down, Mixed for 10 minutes under vacuum, scraped down, added the
143L, then did a final 5 minute mix, then poured our grains. This
Formula worked very well in a 6061 Seamless aluminum case. The grains
were 1.8 inch diameter, and 6 inches long. 4 grains in the motor, and a
nozzle diameter of .650". Burn time is approximately 1.8 seconds. It
cured quite rapidly, tackless in about 18 hours, but you should let it
sit out for a week or more.

This info is only released as educational info, and is not intended for
use by anyone not already versed in the manufacture of propellant.

If anyone would like more info, please feel free to ask!

--
Ron Zeppin
TRA# 6024 L2
AHPRA
XRAA

=========================================================================
Date:         Thu, 8 Jul 1999 23:04:31 -0400
Reply-To:     Chemical Propulsion Research <CHEMROC@LISTSERV.UGA.EDU>
Sender:       Chemical Propulsion Research <CHEMROC@LISTSERV.UGA.EDU>
From:         "James E. Lanier" <jelanier@BELLSOUTH.NET>
Subject:      Re: Book about Composite Propellants
MIME-Version: 1.0
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-----Original Message-----
From: Ed <edrowe@EROLS.COM>
To: CHEMROC@LISTSERV.UGA.EDU <CHEMROC@LISTSERV.UGA.EDU>
Date: Thursday, July 08, 1999 9:10 PM
Subject: Re: Book about Composite Propellants


>What books do you suggest?
>....Ed
>


    My favorite books might be a little heavy for the average amateur
rocketeer, but not for most scientists. I like George Sutton's "Rocket
Propulsion Elements". I also like Hill/Peterson "Mechanics and
Thermodynamics of Propulsion." Be prepared for an occasional differential
equation.

      For amateur rocketeers, I recommend:

CP Technologies publications. Here one learns how to formulate and cast
composite propellants. This is also an introduction to engineering of motors
with the aid of software and graphs.

Gas Dynamics Labs "Designing Rocket Motors".Here one learns how to design
motors as well as characterize propellants and predict flight performance.
Formulas are derived simply and algebraically. The techniques in this book
work with practically any propellant. You also learn how to write your own
computer modeling programs. This is my book. blush blush. I have a web page
that describes the book in more detail.

I can't recommend any of the black powder motor books I've seen. They just
aren't scientific. So many amateur rocket publications are "cook books".
While it may be fun for some to follow instructions and assemble a
motor...it isn't science.

All the best,

Jim

=========================================================================
Date:         Fri, 9 Jul 1999 00:24:43 -0600
Reply-To:     Chemical Propulsion Research <CHEMROC@LISTSERV.UGA.EDU>
Sender:       Chemical Propulsion Research <CHEMROC@LISTSERV.UGA.EDU>
From:         Brian Kosko <bkosko@FLASH.NET>
Subject:      Re: Book about Composite Propellants
MIME-Version: 1.0
Content-Type: text/plain; charset="iso-8859-1"
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We've used the book by Firefox and the one by CP technologies. While both
strike me as very poorly organized they both have useful stuff in them. The
Firefox book has a lot of example formulations that can be tried and/or
modified. We've made really nice standard composite propellant as well as a
red one and an awesome black, smoky, sparky one by using variations of
Gary's formulations.

The CP book has some good rocket engineering data buried in it. It's where I
get formulas for calculating chamber pressure, nozzle throat diameter, and
propellant characterization.


=========================================================================
Date:         Fri, 9 Jul 1999 07:59:31 -0500
Reply-To:     Chemical Propulsion Research <CHEMROC@LISTSERV.UGA.EDU>
Sender:       Chemical Propulsion Research <CHEMROC@LISTSERV.UGA.EDU>
From:         Terry McCreary <terry.mccreary@MURRAYSTATE.EDU>
Subject:      Re: Book about Composite Propellants
Mime-Version: 1.0
Content-Type: text/plain; charset="us-ascii"

>>What books do you suggest?
>>....Ed

The most straightforward book for the amateur unfortunately appears to be
out of print. "How to Formulate and Process Composite Propellant" by Gordon
Campbell, Propulsion Systems Incorporated.

I have a colleague who is a genuine rocket scientist (PhD in aero.
engineering, working on combustion processes of composite propellant). If
he's not mistaken, there IS no book on the nuts-and-bolts of making
composite propellant, other than the self-published ones we already know.
In fact he borrowed my copy of Campbell's book to read and finds it useful.

(Incidentally, my colleague's method of propellant making involves a ziploc
bag and 50 gram batches. Very small scale.)


>CP Technologies publications. Here one learns how to formulate and cast
>composite propellants. This is also an introduction to engineering of motors
>with the aid of software and graphs.

I don't have the newest edition of this. But the quality of the previous
publications that I do have indicate that this is probably the best "nuts &
bolts" book for the experimental rocketeer. At least for now... :-)


>Gas Dynamics Labs "Designing Rocket Motors".Here one learns how to design
>motors as well as characterize propellants and predict flight performance.
>Formulas are derived simply and algebraically. The techniques in this book
>work with practically any propellant. You also learn how to write your own
>computer modeling programs. This is my book. blush blush. I have a web page
>that describes the book in more detail.

Note: this is not a book on propellant making. It describes design of
rocket motors, predicting performance, etc. For those of you who have
trouble understanding Sutton's math, this is the book. You do need an
algebra background.   I can HIGHLY recommend it.     No, I don't get a kickback...


>I can't recommend any of the black powder motor books I've seen. They just
>aren't scientific. So many amateur rocket publications are "cook books".
>While it may be fun for some to follow instructions and assemble a
>motor...it isn't science.

True, it isn't science. However, the initial motivation for most
experimentalists is to make a *working* rocket motor. For that purpose, the
"Best of AFN" books (II and III) have some good "how-to" information on
blackpowder skyrockets.

Once one has make a working motor, the science tends to creep in.

Teleflite's new book will undoubtedly be a major addition to the
experimentalist community. The problem is that publication has been delayed
over and over since about 1990 or 91.

BP motors are considered by many workers to be harder to get to work
properly. The average amateur will be more likely to succeed by making
composite propellant motors.

The Firefox book has a wealth of information. However, as Jim noted, some
of it is incorrect, some is misleading, some terms are used improperly.
Some formulations do not cure properly, at least in my hands. I'd recommend
it for the individual who has been successful in composite motor
construction. That individual should be able to discount much of the
incorrect info.

There was a book put out by Digatek some time ago and advertised in the back
of Popular Science. I don't know if it's still available but the material
on composite propellant has a fair bit of misleading information, and some
which is just plain dangerous (rule #14: the port area must be GREATER than
the nozzle throat area, else you and your motor will suffer).

The McCreary book on composite propellant is...still under construction.
Sorry. I'm slow too.

Last point: spend your money on books at first. Otherwise six months in
the home lab will save you an afternoon of reading. :-(    I've spent about
$400+ on books and publications related to rockets and propellant. And I've
not got all that I want yet.

P'rfesser

=========================================================================
Date:         Fri, 9 Jul 1999 13:54:57 -0400
Reply-To:     Chemical Propulsion Research <CHEMROC@LISTSERV.UGA.EDU>
Sender:       Chemical Propulsion Research <CHEMROC@LISTSERV.UGA.EDU>
From:         Americo Borza <aborza@NETZERO.NET>
Subject:      Re: Fuel problems
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Hi Stephen,

I have read about hazards with molten AN in industrial settings. I have read that the
accidents involved the use of copper or bronze pipes or fittings and the problems occurred
in
the transportation of large amounts of molten AN. At home the temps can be easily controlled
to a couple degrees and all cupric contaminants can be easily avoided. None the less,
I treat
the melting of AN as well as ALL other propellant experiments in exactly the same way
I treat
a diamond back rattlesnake (we have lots of them here in Florida). That is, with a great
deal
of respect! I have only used small amounts in my experiments and all were conducted with
no
"surprises".

In this regard, take heed that I DID NOT melt Sucrose and AN. Check the decomp temp of
AN and
the melting point of Sucrose. I did melt AN and added Sucrose, but the Sucrose WAS NOT
MELTED!
I did melt Sorbitol and AN. Check the melting and decomp temps of that combo. I have also
tried a variety of AN and KNO3 formulations with a variety of binders that were not pressed.
The most promising of which were the NC lacquer binders due to their energetic nature.
I have
not tried Shellac as a binder as you have.The fuels were Sucrose, Sorbitol and Carbon
(charcoal) and additives included Zeolites and Silicon (NOT Silicone).

I, like you, have concluded that propellants made with evaporative binders (NC lacquer
and
Shellac) MUST be pressed to eliminate the micro porous nature of the grain if not pressed.
The
strength also goes way, way up. However, I have not yet developed an appropriate press.

In regard to results, I have found that the melted AN grains I have made are woefully
lacking
in strength and are not acceptable for all the reasons a weak grain should not be used.
I have
also found that the non pressed evaporative binder grains are also very weak and that
coupled
with their micro porous nature gives them two strikes in a game in which one strike and
you're
out.

All of the high AN content grains of any type (with the exception of those bound with
NC
lacquer) would not burn in open air. This is a safety feature to me! Those who do not
know
that the chamber pressure at which the propellant must work is vastly higher than open
air and
the effect of that pressure should not be experimenting in this field.

The beauty of AN propellants is found in their safety, low molecular wt exhaust,       high
ISP and
low exhaust signature. I know that you have made giant strides in the development of   such
propellants. Please tell us of your successes. Include the formulations, process       of
creating
the grains, Chamber Pressures, a, n, and Isp. Have you had any problems due to the     temp
phase
changes or the hygroscopicity of the grains?

BTW did you eventually order any Si from the source I gave you?

Cheers

ab

"Stephen J. Holden" wrote:

> Michael,
> I think that melting AN is a very hazardous operation. Their have been numerous industrial
> accidents with molten AN. The melting temperature is very close to the decomposition
> temperature of AN which does not leave much room for error.
>
> Americo Borza has experimented with sucrose/AN mixtures and has found that they don't
burn
> at atmospheric pressure. Americo, if you are reading this post then please post a comment.
>
> Have a good day, Stephen.


=========================================================================
Date:         Fri, 9 Jul 1999 16:01:12 +1000
Reply-To:     Chemical Propulsion Research <CHEMROC@LISTSERV.UGA.EDU>
Sender:       Chemical Propulsion Research <CHEMROC@LISTSERV.UGA.EDU>
From:         "Stephen J. Holden" <rocket@ACEPIA.NET.AU>
Subject:      Re: Fuel problems
MIME-Version: 1.0
Content-Type: text/plain; charset=us-ascii
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Gooday Americo,
I finally got the silicon powder (1-5 micron) form your source and also purchased the
more pure
industrial grade of AN and have made my own charcoal for the composition. I have mixed
some
different compositions and have found it not to be as reactive as charcoal. It does burn
very well
with both NaNO3 and KNO3 and this has lead me to the conclusion that compositions containing
both
AN and KN may be the way go.

I have successfully phase stabilized AN with 20% of KN. Presently, I am ball milling 1
kg of this
as fine as possible. Then I am going to start by mixing up a batch of propellant with
the
following composition:

7% Silicon
7% Charcoal (pine)
86% Phase Stabilized AN

To this I am going to add 7-8% Ethyl Alcohol/shellac Solution (20%Shellac: 80% Alcohol).

The KN content has the added advantage of improving combustion efficiency, burning rate,
and
igniterbility at atmospheric pressure. Unfortunately, the KN will lower Isp, and produce
more
smoke. However, the vast improvement in burning is well worth the lower Isp. The addition
of more
silicon and less carbon will still boost the Isp to over 230 s (frozen), however, this
depends on
whether the silicon powder burns efficiently without residue.

Thorough mixing may be necessary with these types of compositions, but lets see and I
will get
back to you.

I did realize that you are melting the AN and not the sucrose. The only thing that worries
me
about the method is that you are assuming that the ingredients (Si, C) are not going
to have a
catalytic effect on the decomposition of the molten AN. Perhaps, the materials (Si, C
or various
sugars) may bring the decomposition temperature of the AN closer to the melting temperature
of the
AN. There is not much room for error anyway, but this is just an idea.

I must say that the best compositions are those that contain both AN and KN and C
(Ammidpulver)
that are finely milled together. They burn at astonishing rates and are ignite easy to
ignite but
still much safer than BP. These types of compositions could easily replace BP in BP motors
and
will be over double the Isp of BP. (I have obtained burn rates almost that of BP).

The graines that I have been working with have satisfactory mechanical strength as can
be
ascertained without proper testing.
The ease with which shellac can be mixed with the propellant and availability makes it
the choice
for me.

Anyway, we are going to test the mechanical strength of the propellant strands using
different
binder percentages and different loading pressures. Also, we are going to find the maximum
burn
rate composition (and determine a and n) and the optimum Isp. Also, we are going to test
the
igniterbility. The project is well underway, and at the moment we are building the
equipment for
the testing. This includes a strand burner, press mould to form the strands, igniterbility
test
rig, a small ball mill for mixing small batches of propellant and a small dehydrator.

I have found that the best way to store hygroscopic propellants is in a dessiccator. If
you do
this you will not have a problem with hygroscopic propellants.

As of yet I have not had any observable problem with phase transition. The Ammonpulver
(85% AN:
15% C) grains have been in storage for about 6 months without a problem (cracking). However,
some
testing is necessary. We will endeavour to temperature cycle the propellant strands above
32 Deg.
C and test mechanical strength and burning rate, if time permits. But, it may be the case
that
phase stabilization is only necessary for long term storage such as for military
applications.

Keep me up to date with your experiments (as well as Richard Nakka's) and I will let you
know of
the results as I get them....Stephen.


=========================================================================
Date:         Fri, 9 Jul 1999 19:55:25 -0700
Reply-To:     Chemical Propulsion Research <CHEMROC@LISTSERV.UGA.EDU>
Sender:       Chemical Propulsion Research <CHEMROC@LISTSERV.UGA.EDU>
From:         The Silent Observer <silent1@IX.NETCOM.COM>
Subject:      Re: Linseed oil
MIME-Version: 1.0
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Michael wrote:
>
> Hello,
>
> Linseed oil polymerises when exposed to air. Is there any chemical that could be added
in
> small amounts to cause the same thing to happen, only faster.
> It might allow linseed oil to be uses as a cheap and cheerful binder.

Go to any artist's supply shop and ask for Cobalt Drier. This is a dark
blue solution that speeds the curing of linseed oil (and other linoleic
oils, such as used in artists' colors and old style house paints --
cottonseed oil is one such) by about a factor of five or more, depending
on mix ratio.

I used to use a little of it in oil painting to get a painting that
would be dry enough to handled in 24 hours, instead of a week or more.
Note, however, that this was in paint films, not in thick casting as
you'd use in making rocket motors.

Another option might be to find out what else is in the mixture of the
temporary filling mix sold in drugstores -- the label lists zinc oxide
and oil of clove, but I'm pretty certain those two chemicals won't
undergo an epoxy-like reaction as the filling material does. Whatever
it is, the mixture forms a hard, white material in about 20 minutes from
mixing, with seemingly little or no exotherm.

--
 WARNING!!   This area has been designated an official DOPE FREE ZONE!!

      If you're going to be a dope, please do it somewhere else!

Donald Qualls, aka The Silent Observer           NAR # 70141-SR Insured
Rocket Pages             http://members.aol.com/silntobsvr/launches.htm

Opinions expressed are my own -- take them for what they're worth
and don't expect them to be perfect.
=========================================================================
Date:         Sat, 10 Jul 1999 01:10:32 -0400
Reply-To:     Chemical Propulsion Research <CHEMROC@LISTSERV.UGA.EDU>
Sender:       Chemical Propulsion Research <CHEMROC@LISTSERV.UGA.EDU>
From:         Americo Borza <aborza@NETZERO.NET>
Subject:      Re: Fuel problems
MIME-Version: 1.0
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G'day Stephen,

What follows are some discussions and a few questions.

"Stephen J. Holden" wrote:

> Gooday Americo,
> I finally got the silicon powder (1-5 micron) form your source and also purchased the
more pure
> industrial grade of AN and have made my own charcoal for the composition. I have mixed
some
> different compositions and have found it not to be as reactive as charcoal. It does
burn very well
> with both NaNO3 and KNO3 and this has lead me to the conclusion that compositions
containing both
> AN and KN may be the way go.

I too felt that a combo of AN and KN could work well, but with a bit of a loss in Isp.
I chose to try
the melting and evaporative binder process, while you chose the pressed grain. I think
you were going
in the proper direction but I had to give the others a go. In the above paragraph you
mention that
"it" is not as reactive a charcoal. I assume you mean Si. Its addition was really intended
to increase
heat of combustion and thereby increase combustion efficiency and burn rate as well as
stabilize the
burn rate in regards to temp variations. The goal is to thereby increase stability and
to increase
Isp. BTW what wood have you used for the charcoal?
> I have successfully phase stabilized AN with 20% of KN. Presently, I am ball milling
1 kg of this
> as fine as possible. Then I am going to start by mixing up a batch of propellant with
the
> following composition:
>
> 7% Silicon
> 7% Charcoal (pine)
> 86% Phase Stabilized AN
>
> To this I am going to add 7-8% Ethyl Alcohol/shellac Solution (20%Shellac: 80% Alcohol).

What process do you use to create a molecular mix of the AN and KN. The patents suggest
melting and/or
dissolution and quick dry process. Are you relying only on fine grinding? If so I would
question the
result re phase stabilization. Tests will show though.

> The KN content has the added advantage of improving combustion efficiency, burning rate,
and
> igniterbility at atmospheric pressure. Unfortunately, the KN will lower Isp, and produce
more
> smoke. However, the vast improvement in burning is well worth the lower Isp. The addition
of more
> silicon and less carbon will still boost the Isp to over 230 s (frozen), however, this
depends on
> whether the silicon powder burns efficiently without residue.

Yes. The high molecular wt of the KN exhaust products certainly reduce the Isp. But
sometimes
compromises are in order.

> Thorough mixing may be necessary with these types of compositions, but lets see and
I will get
> back to you.

My ear is to the ground.

> I did realize that you are melting the AN and not the sucrose. The only thing that
worries me
> about the method is that you are assuming that the ingredients (Si, C) are not going
to have a
> catalytic effect on the decomposition of the molten AN. Perhaps, the materials (Si,
C or various
> sugars) may bring the decomposition temperature of the AN closer to the melting
temperature of the
> AN. There is not much room for error anyway, but this is just an idea.

I appreciate your concern. Indeed the results of the melting experiments with AN did show
a physical
result significantly different than that obtained with KN. The cooled AN melts were simply
different,
weak, frosty looking and quite waxy. There may well have been a molecular effect that
could have done
what you suggest. However, I had no problems in doing them. In any event I think the issue
is moot. I
feel the right way to go about it is by pressing, as you have done.

> I must say that the best compositions   are those that contain both AN and KN and C
(Ammidpulver)
> that are finely milled together. They   burn at astonishing rates and are ignite easy
to ignite but
> still much safer than BP. These types   of compositions could easily replace BP in BP
motors and
> will be over double the Isp of BP. (I   have obtained burn rates almost that of BP).
I will soon have to put a press together to see this for myself. This propellant seems
as easy or
easier to make than BP and with typical BP tools one could get a huge increase in Isp
with a great
increase in safety as well. It seems to be a breakthrough. BTW, what do you do to keep
the AN dry
during the milling process?

> The graines that I have been working with have satisfactory mechanical strength as can
be
> ascertained without proper testing.
> The ease with which shellac can be mixed with the propellant and availability makes
it the choice
> for me.
>
> Anyway, we are going to test the mechanical strength of the propellant strands using
different
> binder percentages and different loading pressures. Also, we are going to find the
maximum burn
> rate composition (and determine a and n) and the optimum Isp. Also, we are going to
test the
> igniterbility. The project is well underway, and at the moment we are building the
equipment for
> the testing. This includes a strand burner, press mould to form the strands,
igniterbility test
> rig, a small ball mill for mixing small batches of propellant and a small dehydrator.
>
> I have found that the best way to store hygroscopic propellants is in a dessiccator.
If you do
> this you will not have a problem with hygroscopic propellants.
>
> As of yet I have not had any observable problem with phase transition. The Ammonpulver
(85% AN:
> 15% C) grains have been in storage for about 6 months without a problem (cracking).
However, some
> testing is necessary. We will endeavour to temperature cycle the propellant strands
above 32 Deg.
> C and test mechanical strength and burning rate, if time permits. But, it may be the
case that
> phase stabilization is only necessary for long term storage such as for military
applications.

The phase issue is typically not a problem for an amateur. We can control temp very easily,
unlike the
military. Many have said it is a bugaboo. I doubt it.

> Keep me up to date with your experiments (as well as Richard Nakka's) and I will let
you know of
> the results as I get them....Stephen.
>

My experiments are temporarily on hold. I have some home remodeling to do. But I will
get back to them
soon. Keep up the good work.

ab


=========================================================================
Date:         Sat, 10 Jul 1999 08:34:43 -0500
Reply-To:     Chemical Propulsion Research <CHEMROC@LISTSERV.UGA.EDU>
Sender:       Chemical Propulsion Research <CHEMROC@LISTSERV.UGA.EDU>
From:         Terry McCreary <terry.mccreary@MURRAYSTATE.EDU>
Subject:      Chamber pressure from burn time
Mime-Version: 1.0
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At 08:23 PM 7/9/99 -0400, you wrote:

>How do you get chamber pressure from burn time only, or do you measure
>thrust at the same time? I measure thrust, and with the burn time can
>calculate chamber pressure although I have to estimate the thrust
>coefficient.

P = Kn * Isp * rate * density

Units: Isp = sec (characteristic Isp, Cf not included); rate = in/sec;
density= lb/in^3. P = psi. Use a neutral Bates grain and assume that the
burn rate is constant.

Warning: this gives an estimate of chamber pressure. I've found it to be
useful enough for designing and characterizing motors, but would not rely on
the value. Errors: burn rate isn't really constant; characteristic Isp
isn't necessarily obtained; Isp varies with pressure, etc.

P'rfesser

=========================================================================
Date:         Sat, 10 Jul 1999 10:40:03 -0700
Reply-To:     Chemical Propulsion Research <CHEMROC@LISTSERV.UGA.EDU>
Sender:       Chemical Propulsion Research <CHEMROC@LISTSERV.UGA.EDU>
From:         "Gary C. Rosenfield" <garyr@POWERNET.NET>
Subject:      Re: Chamber pressure from burn time
Mime-version: 1.0
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I've used the following formula for years to estimate chamber pressure from
thrust at any point in the burn. It's accurate to about +/- 5% with typical
AP/HTPB propellants at pressures greater than 100 PSI:

P in PSI = ((Thrust in lbs/Throat Area in sq in) * .616) + 32

It's a curve fit I worked out while employed at Aerojet during the early '80s.


=========================================================================
Date:         Sat, 10 Jul 1999 13:59:33 -0600
Reply-To:     Chemical Propulsion Research <CHEMROC@LISTSERV.UGA.EDU>
Sender:       Chemical Propulsion Research <CHEMROC@LISTSERV.UGA.EDU>
From:         Brian Kosko <bkosko@FLASH.NET>
Subject:      Re: Chamber pressure from burn time
MIME-Version: 1.0
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I use a slightly different formula to calculate Chamber Pressure from just
the Burn Time. It's:

       Ch Pr = (C* x PWF) / (32.2 x TA)

                   C*:   Get this from Propep. It's unique for each
formulation.
               PWF: Prop Wt Flow. Divide Prop Wt by Burn Time for this.
                  TA: Area of the Nozzle Throat

        Once I get the Chamber Pressures, I plot the Log of them vs the Log
of the Burn Rates to get the Pressure Exponent. Once you have the Burn Rate
equation for the propellant you can rearrange the above equation to figure
out what throat size you need to get a desired Chamber Pressure. I find this
especially handy so I don't have to enrich Gary too much by constantly
having to replace my reload cases!
Brian

=========================================================================
Date:         Sat, 10 Jul 1999 17:59:50 -0400
Reply-To:     tbinford@frontiernet.net
Sender:       Chemical Propulsion Research <CHEMROC@LISTSERV.UGA.EDU>
From:         Tom Binford <tbinford@FRONTIERNET.NET>
Subject:      Re: Chamber pressure from burn time
MIME-Version: 1.0
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Terry McCreary wrote:
>
> At 08:23 PM 7/9/99 -0400, you wrote:
>
> >How do you get chamber pressure from burn time only, or do you measure
> >thrust at the same time? I measure thrust, and with the burn time can
> >calculate chamber pressure although I have to estimate the thrust
> >coefficient.
>
> P = Kn * Isp * rate * density
>
> Units: Isp = sec (characteristic Isp, Cf not included); rate = in/sec;
> density= lb/in^3. P = psi. Use a neutral Bates grain and assume that the
> burn rate is constant.

I use this equation, but I measure thrust and from the propellant weight
get Isp. I guess you can use ProPep Isp figures, but I've gotten actual
Isp figures both above and below ProPep's value (depending on
propellant).

Tom

=========================================================================
Date:         Sat, 10 Jul 1999 18:58:03 -0400
Reply-To:     Chemical Propulsion Research <CHEMROC@LISTSERV.UGA.EDU>
Sender:       Chemical Propulsion Research <CHEMROC@LISTSERV.UGA.EDU>
From:         "James E. Lanier" <jelanier@BELLSOUTH.NET>
Subject:      Re: Chamber pressure from burn time
MIME-Version: 1.0
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Your formula is actually identical to the one Terry mentioned.

Where you show:

>       Ch Pr = (C* x PWF) / (32.2 x TA)


This is based on the assumption that:

Thr=Pc(At)

and

Thr=c*(mfr)       mfr=(wfr/32.2)

Therefore

Pc=c*(mfr)/At

c*/32.2 is equal to Isp* that Terry refers to and mfr(32.2) is weight flow
rate.
Substituting gives:

Pc=Isp*wfr/At
wfr=(weight density)(burn rate)

so:

Pc=Isp*(dens)(r)(Kn)

As Terry pointed out, this form does not include Cf.

Thrust actually is equal to c*(mfr)(Cf)

and

Thrust=Pc(At)(Cf)

Cf without an expansion section is about 1.2 (theoretical) for pressures we
generally deal with. Throw in some losses and expect to see a Cf of about
1.15 or so.

Jim


=========================================================================
Date:         Mon, 12 Jul 1999 00:13:44 +1000
Reply-To:     Chemical Propulsion Research <CHEMROC@LISTSERV.UGA.EDU>
Sender:       Chemical Propulsion Research <CHEMROC@LISTSERV.UGA.EDU>
From:         "Stephen J. Holden" <rocket@ACEPIA.NET.AU>
Subject:      Re: Fuel problems
MIME-Version: 1.0
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Americo,
You presumed correct (sorry for my typing mistakes). The Si does not burn as efficiently
in the
composition as expected as it tends to leave unburned Si behind. If I mix just the silicon
with the AN I
find that the material is almost impossible to ignite and does not seem to burn. With
KNO3 however, it
burns well. Also, the more C that is added to the composition to replace the Si, the more
that combustion
improves (easier to ignite, burns cleaner and at higher rates) which seems to go against
the patents
results (we may have to use small percentages of Si as the patent suggests and be happy
with the lower
Isp). However, this is from hand mixing and not machine mixing. Also, they are from
observation and
testing is absolutely necessary to tell one way or the other, what is the best composition
is for amateur
use.

If the Si does not burn efficiently in the composition then we are going to lower measured
Isp than
theoretical Isp.

The process for stabilization is very simple. Simply make up a concentrated solution of
20% KNO3 and 80%
AN with the correct amount of water at 65 Deg. C. Then pour this hot solution to a thickness
of 1 cm onto
drying dishes and place these in a dehydrator at 65 Deg. C for 3 days to dry. Once it
has caked up
sufficiently push the crumbly material through a course screen (or ball mill for an hour)
to reduce the
clumps. And dry this for a further 24 hr until completely dry. Then ball mill to a fine
powder.

I am almost convinced at this stage that one must treat the mixture almost like BP to
get good burning
(though grinding and mixing) .

To keep the AN dry during the processing is absolutely important. The slightest amount
of moisture will
cause it to cake up in the mill. First, always dehydrate the AN before milling for 24
hr's. Then, simply
mill it for the required time. Then store the AN in glass containers with the seal smeared
with grease.
Also. place attach a small bag of silica gel in the lid to catch any moisture due to
repeated opening of
the container.

By the way Americo, do you have any ideas about plasticizes that could be added to the
Shellac. I am
thinking that one could increase the percentage of shellac by reducing the percentage
of C and take the
benefit of a plasticized shellac.

Have a good day, Stephen.


=========================================================================
Date:         Sun, 11 Jul 1999 15:45:16 +1000
Reply-To:     Chemical Propulsion Research <CHEMROC@LISTSERV.UGA.EDU>
Sender:       Chemical Propulsion Research <CHEMROC@LISTSERV.UGA.EDU>
From:         "Stephen J. Holden" <rocket@ACEPIA.NET.AU>
Subject:      Re: AN/Si burn efficiency was Re: Fuel problems
MIME-Version: 1.0
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> >You presumed correct (sorry for my typing mistakes). The >Si

> does not burn as efficiently in the

> >composition as expected as it tends to leave unburned Si >behind.

>   If I mix just the silicon with the AN I
>   >find that the material is almost impossible to ignite and >does
>   not seem to burn.
>
>   Have you tried adding a little Fe2O3? I've been able to make
>   very fast burning (by nitrate standards, anyway) KNO3/Si/Epoxy
>   propellant by adding 3-5% Fe2O3. The burn rate is *drastically*
>   improved -- whether due to the catalytic effect on the oxidizer,
>   a direct (thermite) reaction between the iron oxide and Si or
>   a little of both, I don't know. But it works.
>
>   The progression I went through using KNO3 as an oxidizer (and
>   occasionally substituting AN for the KNO3) was:
>
>   1.   Epoxy binder only -- no burn
>   2.   Al (47mic)/Epoxy -- no burn
>   3.   Mg (19mic)/Epoxy -- great burn, but the Mg scares me
>   4.   Si (size?)/Epoxy -- slow burn, lots of residue
>   5.   Si/Fe2O3/Epoxy -- great burn, fast as 20% Mg!
>
> I'm using black pyro Si. Both the silicon and iron oxide are
> from Firefox. KNO3 is technical grade, ground up a bit in a
> blender.
>

=========================================================================
Date:         Sun, 11 Jul 1999 16:23:49 +1000
Reply-To:     Chemical Propulsion Research <CHEMROC@LISTSERV.UGA.EDU>
Sender:       Chemical Propulsion Research <CHEMROC@LISTSERV.UGA.EDU>
From:         "Stephen J. Holden" <rocket@ACEPIA.NET.AU>
Subject:      Re: AN...water
MIME-Version: 1.0
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Gooday Jim,
Thanks for your informitive comments. I did consider that agglomerates of molten
silicon dioxide may form (propep does infact show to large amounts of solid
phase glass in the combustion products, but I was not certain if they would
agglomerate as you suggest). It may be possible to go above 8 % with the
addition of the KNO3 and if the burn rate is high enough. Fine milling may help
this. I am curious how you arrived at 8 %. Perhaps with other compositions this
may be increased! I certainly believe you from my testing, so far, but is the
residue glass or is it unreacted Si?

I think that you are correct that unless the binder content can be increased
significantly, the addition of the plasticizes to the shellac are not going to
help much, but I wanted to just evaluate the idea.

I have tried mixtures of Al and AN, with iron oxide as the catalyst and epoxy as
the binder. If on adds some KNO3 to this type of compositions they do burn
furiously. I have only tryed this with large particle size Al powder, but these
are very difficult to ignite. You need some thermite to get it started. However,
finer Al powders may work satisfactorily.

All the best......Stephen.


James E. Lanier wrote:

>   >Jim,
>   >Someone sent this data to me. Unfortunately, I can not remember who it
>   >was. I can remember that they did not give the source in the post,
>   >however...Stephen.
>
>   Thanks.
>
>   By the way, I warned you about the excessive use of silicon back in March I
>   think it was....lol. Propep just doesn't predict some things. You need to
>   stay below about 8 percent to avoid a lump of glass.
>   The best way to solve your binder problems is to abandon the shellac and go
>   with nitrocellulose. Nitrocellulose can be plasticized, but consider
>   this....AN formulations have such high solids loading that you would not be
>   able to tell the difference. Unless you get binders (and I mean
>   crosslinking polymers) in percentages of 14 percent or more, the grain is
>   just going to be hard. I made an AN propellant with HTPB of about 10 percent
>   and it was very dry and very hard as expected. High percentages of polymeric
>   binders can not be used with AN unless you go with Magnesium. Then you can
>   have high impulse motors with 17-18 percent binder. Aluminum works with AP
>   but is not very compatible with AN propellants. (propep again wont show
>   this). You can take AN and magnesium alone and get a fierce reaction. You
>   would probably not even be able to light aluminum and AN.
>   Magnesium/AN propellants have Isp values VERY close to that of AP
>   propellants...but Magnesium is expensive to ship.
>
>   Keep working and good luck,
>
> Jim


=========================================================================
Date:         Sun, 11 Jul 1999 07:17:03 -0400
Reply-To:     Chemical Propulsion Research <CHEMROC@LISTSERV.UGA.EDU>
Sender:       Chemical Propulsion Research <CHEMROC@LISTSERV.UGA.EDU>
From:         "James E. Lanier" <jelanier@BELLSOUTH.NET>
Subject:      Re: AN...water
MIME-Version: 1.0
Content-Type: text/plain; charset="iso-8859-1"
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>this. I am curious how you arrived at 8 %. Perhaps with other compositions
this
>may be increased! I certainly believe you from my testing, so far, but is
the
>residue glass or is it unreacted Si?


Trial and error. Like you, I wanted to maximize Isp. But I soon found that I
had to reduce the Si content significantly.

>I have tried mixtures of Al and AN, with iron oxide as the catalyst and
epoxy as
>the binder. If on adds some KNO3 to this type of compositions they do burn
>furiously. I have only tryed this with large particle size Al powder, but
these
>are very difficult to ignite. You need some thermite to get it started.
However,
>finer Al powders may work satisfactorily.


This is interesting. I too noticed the way the An/Si mixture burned well
with KNO3. I'll bet Ammonium Dichromate works even better. I don't remember
trying KNO3 with AN/Al, but thanks for the tip.
    Just curious Stephen...what kind of chamber pressures are you using?
Have you measured "a" and "n" with your formulations? If you are working on
a patent or something I will understand if you don't want to give up
details...lol.

Good Luck Stephen,

Jim


=========================================================================
Date:         Mon, 12 Jul 1999 10:29:35 +1000
Reply-To:     Chemical Propulsion Research <CHEMROC@LISTSERV.UGA.EDU>
Sender:       Chemical Propulsion Research <CHEMROC@LISTSERV.UGA.EDU>
From:         "Stephen J. Holden" <rocket@ACEPIA.NET.AU>
Subject:      Re: AN...water
MIME-Version: 1.0
Content-Type: text/plain; charset=us-ascii
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Jim,
As of yet, I have not tested for a and n with propellant compositions containing
the KNO3. This will be the major part of our project. I can only hope that the
propellant will yield suitable values. As far as chamber pressure go, we are
going up to a maximum of about 1200 psi for the strand burning. It was the
opinion that this range would yield sufficient data for most amateur motors.
But, I would like to here from anybody who thinks that higher pressures are in
order!
I have considered the idea of patenting this idea, but the costs involved are
just extraordinary and unless their is a very definite market the money is
basically wasted.
Also, patents don't necessarily protect your idea.
Before considering this, the propellant must be tested and satisfactory results
for the intended application obtained. My real aim, is that this work will go
towards my final year project (thesis) for my Bachelor of Engineering Degree
(Mechanical). However, most importantly it is to provide a propellant that is
safe to produce and with consideration to the environment, for all those
rocketeers out their. With this in mind, I may write a book
that covers every aspect of this kind of propellant and rocket motor design. It
is also my way to pursue my interest in rocketry.......one of the greatest
learning experiences that you will ever have...I have learned more in this field
than I would doing 10 Degrees.

All the best, Stephen.

=========================================================================
Date:         Mon, 12 Jul 1999 10:38:56 +1000
Reply-To:     Chemical Propulsion Research <CHEMROC@LISTSERV.UGA.EDU>
Sender:       Chemical Propulsion Research <CHEMROC@LISTSERV.UGA.EDU>
From:         "Stephen J. Holden" <rocket@ACEPIA.NET.AU>
Subject:      Re: Fuel problems
MIME-Version: 1.0
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Here is the link that Americo let me know about for 1-5 micron Silicon powder,
 http://www.micronmetals.com/index5.htm

Stephen.
Lisle Hites wrote:

> --BTW did you eventually order any Si from the source I gave you?
>
> I must have missed the discussion of this particular source, as well as the source for
the AN,
> would your mind repeating it?
>
> Thanks,
> Lisle


=========================================================================
Date:         Tue, 13 Jul 1999 05:51:59 -0400
Reply-To:     weaver_r@mediasoft.net
Sender:       Chemical Propulsion Research <CHEMROC@LISTSERV.UGA.EDU>
From:         Rich Weaver <weaver_r@MEDIASOFT.NET>
Organization: At home in the mountains
Subject:      Re: Free Altitude Program For 32 bit users (win95/98)
MIME-Version: 1.0
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"James E. Lanier" wrote:
>
>     I wrote a simple altitute prediction program that I am giving to ChemRoc
> members. Go to the url and download the .exe file.
>     This is for ChemRoc members only, please do not give this url out.
>
> http://128.192.41.212/altitude/
>

I've used Make Sullivan's program. It is Web based and quite interesting. It
allows you to use common motors or specify your own.
When I went looking for it (bookmark) just now, it was GONE! Well, not lost
though, Infoseek found it at http://hiwaay.net/~bday/hara/altitude.htm

If someone tries both, I would be interested to hear how they compare.

Rich

=========================================================================
Date:         Fri, 16 Jul 1999 15:56:31 -0500
Reply-To:     james.m.rosson@delphiauto.com
Sender:       Chemical Propulsion Research <CHEMROC@LISTSERV.UGA.EDU>
From:         Jim Rosson <jmrosson@KOAME001.DELCOELECT.COM>
Organization: Delphi Automotive - Delco Electronics Systems
Subject:      Re: Ignitor binders
Comments: To: Mark Casteel <casteelm@info2000.net>
Comments: cc: arocket@nmt.edu
MIME-Version: 1.0
Content-Type: text/plain; charset=us-ascii
Content-Transfer-Encoding: 7bit

They say if you share, life will be better and it will be returned in
spades. So here goes. If you are looking for a good igniter binder,
that doesn't crumble, I have a solution. Here's also some information
on lead/bridge wire sources for the source challenged.

I work with a lot polymers in my day job, and found one that makes a
decent igniter binder. It's a silicone rubber. Ok, it's no big
secret. But, I found one brand at the hardware store, that is readily
available to most people, that's also cheap enough, and it works as
is. (Too bad oxidizer and metals aren't as available :) It is Dow
Corning TradeMate II brand silicone. If you want to substitute a
different brand, make sure it does NOT give off a vinegar smell when
curing, and it might work, but no promises. This one worked for me a
few times. It has one small limitation, after making the compound it
must be used in a single 4-6 hour session. The oxidizer catalyzes the
cure mechanism, and it will cure in sealed jar in 24 hours. It can not
be re-dissolved. It's ok, providing you need to dip alot of iginters at
once, or make small batches. The best part is the igniter can be bent
over double several times, and the compound stays on the wire. It took
me 8-10 bend cycles to get the head to crack. It never really
crumbled. Yet it makes a good igniter.

The compound is dipped on to the classic wrapped bridge wire
configuration similiar to the commercial stuff. If you need to make
your own, the materials are easy to find. Commercial sources exist for
duplex solid copper wire (it's the cheapest), and the Ni/Cr or Ni/Cu
bridge wire. The duplex lead wire can be found at
<http://www.seminolewire.com/>. I find Ni/Cr wire is tough to solder
without vary aggressive flux and silver solder. Finding a decent easily
solderable bridge wire stumps a lot of people. I found a low volume
source in the early days that may help some. You can use constantan
uninsulated thermocouple wire. It's available in small spools from
Omega Engineering <www.omega.com>, info can be found at
<http://pdf.omega.com/temperature/H/pdf/h010.pdf>. You can pick the
diameter based on the intended use. The smaller the wire, the less
current required, but the lower the heat generated. I use 3-8 turns of
0.003" to 0.005" wire for 12V systems, with 2-6 amps current capability,
depending on the purpose (ie single or cluster).

Warning: Do not attempt to make this if you haven't made pyrotechnic
compounds before. It can be very dangerous. Do not mix metal and
oxidizer dry!

The basic formula is;
10 parts DOW TradeMateII clear silicone rubber (from a tube of all
things)
35 parts toluene
40 parts Potassium perchlorate
30 parts Magnesium (-325m spherical) (smaller particles faster, larger
particles slower burn)
1-2 parts iron oxide optional (real fast burn)

Process;
Blend silicone and toluene in clean glass jar until homogeneous (it gets
thrown away and/or burned later, and the silicone won't cure if it's
contaminated)
Add metal, and blend,
Add oxidizer, and blend,
Add iron oxide, and blend, (not required for most people)
Thin with extra toluene to desired consistency (if needed).
Dip iginters.

In about 3-4 hours it starts to get thicker, toluene will thin it,
but not stop the cross linking. After about 6 hours the dip has so much
toluene in it, it will crumble when it cures. Which is what you wanted
to avoid in the first place, Oops! The mix ratios can be varied quite a
bit to achieve different burn rates and characteristics, substract 1-2%
binder(faster, less durable), add 1-5% magnesium(faster, hotter), etc.
You can also add things for larger motors; 2-10% titanium -200m, or 1-5%
zirconium -325m to get more fire/slag generated.
Remember, always wet out the metals in binder, before adding oxidizer.

Be safe.

PS Original posted to AROCKET list, Cross posted to CHEMROC list due to
content, sorry for the redundancy.

Mark Casteel wrote:
>
> Hi guys, does anyone know exactly why the pyrogen on that "popular"
> ematch kit begins to crumble after a couple months? Like said below,
> toluene is the best solvent to reconstitute, is there something else
> that can be added to keep it from disintergrating again? Would I be
> correct in assuming that humidity is the culprit? Would 1 to 3% dextrin
> added to the mix help?
>

--
_______________________________________________________
Jim Rosson
Delphi Delco Electronics Systems
james.m.rosson@delphiauto.com
All opinions expressed are not endorsed by my employer.
_______________________________________________________


=========================================================================
Date:         Thu, 29 Jul 1999 10:17:34 -0500
Reply-To:     Chemical Propulsion Research <CHEMROC@LISTSERV.UGA.EDU>
Sender:       Chemical Propulsion Research <CHEMROC@LISTSERV.UGA.EDU>
From:         Terry McCreary <terry.mccreary@MURRAYSTATE.EDU>
Subject:      Re: Open source rocket science     was:suggestion for website and
              magazine
Comments: To: Brian Garlock <the_geniusboy@hotmail.com>
Comments: cc: arocket@nmt.edu
Mime-Version: 1.0
Content-Type: text/plain; charset="us-ascii"

> Just today I downloaded a spreadsheet only to find that I need
>Quttro Pro. Who uses quattro pro in this day and age (For those of you that
>do, well sorry).
Off-topic comment: you may be talking about my spreadsheet Pro_pel. I use
QPRO for three reasons: it was the first spreadsheet I ever used and I'm
familiar with it; WP Suite with QPRO version 8 cost me $40, while Excel
would have been a good bit more; Microsoft's "progress" with Windows offends
me, and when practical I try to refuse to buy/support MS products.

However, if you wish to convert Pro_pel to .XLS format, please feel free to
do so; just send it to Jim Lanier when you're done so he can post it for
everyone to use.

A more on-topic comment: the library. Web sites are often like one-night
stands; quick'n'dirty. However, it's rather difficult to find USEFUL info,
as you've noted. Most libraries can arrange for interlibrary loan. And if
you annoy the librarian enough, he/she may buy the book you keep getting on ILL.

If you're looking for derivations and simple equations re. solid propellant
rockets, I will again recommend Jim Lanier's book on designing rocket motors.

>That site actually helps me in understanding
>certain aspects of rocket science, though nowhere on the site can I find a
>really good explanation of K sub n

It's there.   See "Propellant Burnrate Testing":

     Kn , referred to as the klemmung of a rocket motor, is the ratio
     of the propellant burning surface area to the nozzle throat area,
     expressed as Ab / A*

P'rfesser

=========================================================================
Date:         Sun, 8 Aug 1999 09:54:39 -0400
Reply-To:     Chemical Propulsion Research <CHEMROC@LISTSERV.UGA.EDU>
Sender:       Chemical Propulsion Research <CHEMROC@LISTSERV.UGA.EDU>
From:         Rich Weaver <weaver_r@MEDIASOFT.NET>
Subject:      Re: lead dioxide plating
MIME-Version: 1.0
Content-Type: text/plain; charset=us-ascii
Content-Transfer-Encoding: 7bit

Mark Pinese wrote:
>
> I remember looking at a site some time ago, called "Chemistry and
> Carpentry", I think, that had detailed instructions for the production
> of chlorates, perchlorates, and various electrodes.

The location has changed to:
http://users.foxvalley.net/~chemengr/

see also:
http://huizen.dds.nl/~wfvisser/indexEN.html

and:
http://www.telusplanet.net/public/dsoucy/elmfg.htm

these folks sell anodes
http://www.electrosynthesis.com/

these sell plating solutions and Pt wire:
http://hooverandstrong.com/products/millprod/plating.htm

This is an interesting site that may or may not have useful information:
http://www.rembar.com/tech2.htm

There are lots of related patents, IBM has a patent search site:
http://www.patents.ibm.com/
Here are a few patents I have bookmarked:
4236978
3887398
4051000
3855084
5683567
4064035

There are many more.

Search to your heart's content for words like anode, lead dioxide, lead
peroxide, PbO2, chlorate, perchlorate, electrowinning etc.

Rich

=========================================================================
Date:         Thu, 12 Aug 1999 12:56:56 -0600
Reply-To:     Chemical Propulsion Research <CHEMROC@LISTSERV.UGA.EDU>
Sender:       Chemical Propulsion Research <CHEMROC@LISTSERV.UGA.EDU>
From:         Brian Kosko <bkosko@FLASH.NET>
Subject:      Re: igniters
MIME-Version: 1.0
Content-Type: text/plain; charset="iso-8859-1"
Content-Transfer-Encoding: 7bit

Adam,

   What size of motors are you talking about? We use a little fine wire and
thermalite to ignite 38mm and 54mm composite motors.


Brian

=========================================================================
Date:         Fri, 13 Aug 1999 18:55:00 +1000
Reply-To:     Chemical Propulsion Research <CHEMROC@LISTSERV.UGA.EDU>
Sender:       Chemical Propulsion Research <CHEMROC@LISTSERV.UGA.EDU>
From:         "Stephen J. Holden" <rocket@ACEPIA.NET.AU>
Subject:      Strand burner question....
MIME-Version: 1.0
Content-Type: text/plain; charset=us-ascii
Content-Transfer-Encoding: 7bit

Hello everyone,

Our propellant project at Swinburne University is going well. All the
equipment is built except for the strand burner and we are going to
start some initial testing of the propellant this coming week.

I have a small question to the group: Would a light dependent resistor
work for the measurement of the burn rate in the strand burner. The idea
is that the burning strand will produce light only when the strand is
burning, so we can use this signal (changing resistance of the light
dependent resistor) to determin the burn time. The advantage of this is
that no wires are needed to cross the strand at each end, to determin
the burn rate, which is quite inaccurate since our strands are only 50
MM in length, due to practical reasons (this is a compressed
composition).

All the best....Stephen.

=========================================================================
Date:         Fri, 13 Aug 1999 13:03:04 SAST
Reply-To:     Chemical Propulsion Research <CHEMROC@LISTSERV.UGA.EDU>
Sender:       Chemical Propulsion Research <CHEMROC@LISTSERV.UGA.EDU>
From:           Gary Ferris <ferrisgary@HOTMAIL.COM>
Subject:        Re: Strand burner question....
Mime-Version:   1.0
Content-Type:   text/plain; format=flowed

Hi Stephen

You should rather use a photo transistor or photo diode as they can perform
at higher speeds than a light dependant resistor. This will be critical if
the burn times are of a short duration.

Good luck
Gary...


=========================================================================
Date:         Sat, 14 Aug 1999 00:38:38 +0100
Reply-To:     Chemical Propulsion Research <CHEMROC@LISTSERV.UGA.EDU>
Sender:       Chemical Propulsion Research <CHEMROC@LISTSERV.UGA.EDU>
From:         Michael <mmcardle@IOL.IE>
Subject:      Re: Strand burner question....
MIME-Version: 1.0
Content-Type: text/plain; charset=ISO-8859-1
Content-Transfer-Encoding: 7bit

----------
> From: Stephen J. Holden <rocket@ACEPIA.NET.AU>
>
> Hello everyone,
>
>
>
> I have a small question to the group: Would a light dependent resistor
> work for the measurement of the burn rate in the strand burner. The idea
> is that the burning strand will produce light only when the strand is
> burning, so we can use this signal (changing resistance of the light
> dependent resistor) to determin the burn time. The advantage of this is
> that no wires are needed to cross the strand at each end, to determin
> the burn rate, which is quite inaccurate since our strands are only 50
> MM in length, due to practical reasons (this is a compressed
> composition).
>
> All the best....Stephen.
>
Hello all,
You are not going to use wires but I will still add my two halfpennies worth..
When using wires that burn away as the strand burns it can be difficult to actually
figure out when the wire has actually gone as the gasses in the burning strand are highly
conductive and will continue to carry the current after the wire has gone and fool the
measuring equipment (and you;-)).

Michael.

=========================================================================
Date:         Fri, 13 Aug 1999 19:43:52 -0400
Reply-To:     Chemical Propulsion Research <CHEMROC@LISTSERV.UGA.EDU>
Sender:       Chemical Propulsion Research <CHEMROC@LISTSERV.UGA.EDU>
From:         "James E. Lanier" <jelanier@BELLSOUTH.NET>
Subject:      Re: Strand burner question....
MIME-Version: 1.0
Content-Type: text/plain; charset="iso-8859-1"
Content-Transfer-Encoding: 7bit

burning strand are highly
>conductive and will continue to carry the current after the wire has gone
and fool the
>measuring equipment (and you;-)).
>
>Michael.


Only with a high impedance circuit. This is not a problem when one does it
correctly. The wave form and frequency of the loop excitation also can be
helpful in discrimination.

Jim

=========================================================================
Date:         Fri, 13 Aug 1999 22:31:23 -0400
Reply-To:     Chemical Propulsion Research <CHEMROC@LISTSERV.UGA.EDU>
Sender:       Chemical Propulsion Research <CHEMROC@LISTSERV.UGA.EDU>
From:         "James E. Lanier" <jelanier@BELLSOUTH.NET>
Subject:      Re: Strand burner question....
MIME-Version: 1.0
Content-Type: text/plain; charset="iso-8859-1"
Content-Transfer-Encoding: 7bit

Hi Stephen,

    Well, an acoustic Time Domain Reflectometer is the equivalent of sonar.
(I use another type of TDR fairly often to measure transmission lines). A
TDR is a transmitter/receiver/timebase. A "ping" is transmitted by
transducer, the reflection follows. The time delay allows calculation of
length. And yes, I know of a strand burner using this principle. Another
method is by acoustic emission analysis. Try a patent search for
this...probably a very common method. Another method (which I like) is a
closed vessel that is allowed to increase in pressure as the strand burns.
The "rate" at which the pressure increases can be analyzed to determine burn
rate. The beauty of this is that you get a and "n" from one burn.
    I don't want to talk about it much right now, but I am developing a
strand burner that is so simple and inexpensive that.....well you'll see.

Later Friend,

Jim

=========================================================================
Date:         Sun, 15 Aug 1999 01:17:16 +1000
Reply-To:     Chemical Propulsion Research <CHEMROC@LISTSERV.UGA.EDU>
Sender:       Chemical Propulsion Research <CHEMROC@LISTSERV.UGA.EDU>
From:         "Stephen J. Holden" <rocket@ACEPIA.NET.AU>
Subject:      Re: Strand burner question....
MIME-Version: 1.0
Content-Type: text/plain; charset=us-ascii
Content-Transfer-Encoding: 7bit

Hi Jim,
Thanks for the very nice explanation. The acoustic method is one I have seen.
Originally,
I was going to use our pressure transducer to measure the burn rate. The problem
that I see is how can it be analysed for an accurate burn rate. Does the signal
at the end of burn
give a sharp enough transition to determine an accurate end of the burning
duration?

All the best Jim...Stephen.


=========================================================================
Date:         Sat, 14 Aug 1999 00:15:09 -0400
Reply-To:     Chemical Propulsion Research <CHEMROC@LISTSERV.UGA.EDU>
Sender:       Chemical Propulsion Research <CHEMROC@LISTSERV.UGA.EDU>
From:         "James E. Lanier" <jelanier@BELLSOUTH.NET>
Subject:      Re: Strand burner question....
MIME-Version: 1.0
Content-Type: text/plain; charset="iso-8859-1"
Content-Transfer-Encoding: 7bit

>that I see is how can it be analysed for an accurate burn rate. Does the
signal
>at the end of burn
>give a sharp enough transition to determine an accurate end of the burning
>duration?
>
>All the best Jim...Stephen.
>


That is hard to answer Stephen. If no heat were lost from the system, the
transition would go from "rising pressure" to "flat" at the end of the burn.
An actual system would have to be calibrated according to actual heat
losses. I will send you a .jpg that shows a typical time-pressure graph one
would get from such a burn if there were no losses.

Jim

=========================================================================
Date:         Fri, 13 Aug 1999 21:24:25 -0700
Reply-To:     Chemical Propulsion Research <CHEMROC@LISTSERV.UGA.EDU>
Sender:       Chemical Propulsion Research <CHEMROC@LISTSERV.UGA.EDU>
From:         Robert Rochte <robert@ROCHTE.COM>
Subject:      Re: Strand burner question
Content-Type: TEXT/PLAIN; charset=US-ASCII

>Another method (which I like) is a closed vessel that is >allowed
to increase in pressure as the strand burns.
>The "rate" at which the pressure increases can be analyzed >to
determine burn rate. The beauty of this is that you get >a and
"n" from >one burn.

(Borrowing from what someone else recently told me...)

Isn't that how the original Crawford Bomb worked? It was self
pressurizing and the burn rate, as well as "a" and "n" (for the
range of pressures) were derived.

If you follow Wickman's instructions in the CP Technologies book
for building a simple strand burner, you will end up at this
solution sooner or later anyway (hint, hint, me too!).

Can anyone comment on the specifics of the data analysis using
this method?

=========================================================================
Date:         Sat, 14 Aug 1999 16:39:40 -0500
Reply-To:     Chemical Propulsion Research <CHEMROC@LISTSERV.UGA.EDU>
Sender:       Chemical Propulsion Research <CHEMROC@LISTSERV.UGA.EDU>
From:         Russell Blink <rblink@PAGER.NET>
Subject:      Re: Strand burner question....
MIME-Version: 1.0
Content-Type: text/plain; charset="iso-8859-1"
Content-Transfer-Encoding: 7bit

Light enters the optical cable only at the end. Normal incident radiation
will be very low compared to the longitudinal (desired) signal. Most cable
comes with jackets anyway. One test burn could easily be used to adjust the
threshold of the optical detectors to trigger only on the flame front as it
passes the cable.
You could just use an acquisition system on the detectors and measure peak
to peak transition time from first cable to second.

Russell


=========================================================================
Date:         Sun, 15 Aug 1999 00:04:47 -0700
Reply-To:     Chemical Propulsion Research <CHEMROC@LISTSERV.UGA.EDU>
Sender:       Chemical Propulsion Research <CHEMROC@LISTSERV.UGA.EDU>
From:         Robert Rochte <robert@ROCHTE.COM>
Subject:      Strand burner / CP Technologies book
Content-Type: TEXT/PLAIN; charset=US-ASCII

>> If you follow Wickman's instructions in the CP
>> Technologies book

>Title?

I was referring to John Wickman's "Making Amateur Rockets" book.
 He has a chapter on making a simple strand burner.

Wickman first describes the established way of doing things (at
least amongst amateurs, from what I've seen) -- using nitrogen
to pressurize the chamber along with a pressure transducer and
suitable DAS.

He then goes on to describe a simplified chamber which is self-pressurized
(by the burning strand) and which uses only a pressure gauge
for instrumentation. The strand is cut to a standard length
(e.g., 1"), sealed in the chamber with an igniter at one end
and the pressure gauge videotaped during the burn.

The burn length is determined by rise time on the gauge. Average
burn rate computed from the rise time and the known length of
the strand. Min and max pressures averaged. Two burns (using
different diameter strands or different size burners or -- as
Wickman alternately suggests -- with extra "chunks" of propellant
burnt in the chamber for pressurization before the strand is
started) and you have enough data to determine "a" and "n".

Obviously, the addition of sensor wires on the strand will add
a good deal to the accuracy of this simple arrangement (suggested
to me as almost necessary by Bill Colburn). My initial burners
based on this info are "disposable" -- made of insulated (with
EPDM) Sched 80 PVC with a pressure gauge hanging off the side
and two mini-lightbulbs running off a couple of AA batteries.
 One lightbulb for the "start" wire and one for the "end" wire
(they blink out when each wire is fried).

Video tape the burn and you have the time constant along with
pressure data and precise start/stop markers. Looks darn simple
to me. Using this method, it should be easy for anyone to derive
decent numbers quickly and inexpensively.

[I know, PVC is a nasty choice, but these small burners will
be at the bottom of a narrow pit about 4' deep when they are
fired up and will be remotely filmed using a mini CCD camera
with *lots* of cable!]

Add to all of this further refinements to the analysis process
(ala the original Crawford Bomb methods) which Jim Lanier might
be able to provide and we'll be moving to "the next level", IMHO!

-----
=========================================================================
Date:         Tue, 24 Aug 1999 09:14:12 -0700
Reply-To:     Chemical Propulsion Research <CHEMROC@LISTSERV.UGA.EDU>
Sender:       Chemical Propulsion Research <CHEMROC@LISTSERV.UGA.EDU>
From:         "Gary C. Rosenfield" <garyr@POWERNET.NET>
Subject:      Re: observation DDI 1410 Aliphatic Diisocyanate
Mime-version: 1.0
Content-type: text/plain; charset="US-ASCII"
Content-transfer-encoding: 7bit

James,

>   It has been my experience that my isocyanate curatives tend to go bad. They
>   lose their effectiveness for a number of reasons. However, DDI 1410
>   aliphatic diisocyanate remains as effective as the day I got it. Perhaps it
>   is less sensitive to moisture ( I live in the Southern US...fairly humid).
>   Just thought I would offer this. Any comments..or arguments?...

You're right, it is less sensitive to moisture because of it's relatively
long-chain aliphatic hydrocarbon backbone. DDI has a tendency to absorb more N2
than the other isocyanates, though.

Gary
=========================================================================
Date:         Wed, 25 Aug 1999 12:12:43 -0500
Reply-To:     Chemical Propulsion Research <CHEMROC@LISTSERV.UGA.EDU>
Sender:       Chemical Propulsion Research <CHEMROC@LISTSERV.UGA.EDU>
From:         Terry McCreary <terry.mccreary@MURRAYSTATE.EDU>
Subject:      Re: observation DDI 1410 Aliphatic Diisocyanate
Mime-Version: 1.0
Content-Type: text/plain; charset="us-ascii"

At 09:14 AM 8/24/99 -0700, you wrote:

>You're right, it is less sensitive to moisture because of it's relatively
>long-chain aliphatic hydrocarbon backbone. DDI has a tendency to absorb more N2
>than the other isocyanates, though.

Hmm... I didn't realize that isocyanates reacted with atmospheric nitrogen.
Or do I misunderstand?

P'rfesser
=========================================================================
Date:         Wed, 25 Aug 1999 12:12:04 -0500
Reply-To:     james.m.rosson@delphiauto.com
Sender:       Chemical Propulsion Research <CHEMROC@LISTSERV.UGA.EDU>
From:         Jim Rosson <jmrosson@KOAME001.DELCOELECT.COM>
Organization: Delphi Automotive - Delco Electronics Systems
Subject:      Re: observation DDI 1410 Aliphatic Diisocyanate
MIME-Version: 1.0
Content-Type: text/plain; charset=us-ascii
Content-Transfer-Encoding: 7bit

FWIW;
The long chain structure, also creates a lower cross link density in a
classic R45 polymer network. This lower cross link density results in a
softer cured polymer with "weaker" mechanical properties (ie lower
modulus, and higher elongation). The reduced mechanical properties of
the rubber binder aren't as critical for small motors (~<54mm & ~<10
L/D), but for larger solid motors a stronger polymer network is needed.
According to my sources, DDI-1410 can be used by itself and is used by
itself without plasticizers to get better mechanical properties. In
large solid motors or high impulse designs where binder strength is
important; DDI-1410 is usually mixed with other isocyanates (aliphatic
and/or aromatic), and/or the R45 binder has other more highly branched
polymers mixed into the blend. Typical examples of these branched
polymer additions include; short chain diols/triols of
polyether/polyester (Dow Chemical Voranol polymers and similar), and
fatty acid triglycerides(castor oil). These branched polymers must be
chosen carefully. The mechanical properties can be made to "strong" (ie
hard and inflexible). The binder needs to be able handle the
pressure/temperature stresses, and not crack or fail during combustion.
It's fine line.

PS There's a whole another science to the mechanical properties required
in a motor, most of it beyond the amateur's capabilities (unless they
have strength of materials testing & finite element analysis
capability).

Regards....


=========================================================================
Date:         Thu, 26 Aug 1999 15:09:58 +0200
Reply-To:     Chemical Propulsion Research <CHEMROC@LISTSERV.UGA.EDU>
Sender:       Chemical Propulsion Research <CHEMROC@LISTSERV.UGA.EDU>
From:         Javier D <javier.d@TELELINE.ES>
Subject:      Re: AN catalysts and ammonium dichromate
MIME-Version: 1.0
Content-Type: text/plain; charset="iso-8859-1"
Content-Transfer-Encoding: 7bit

The best catalysts for AN composite is the first Ammonium Dichromate and the
second and cheapest is Potassium Dichromate, both are little carcinogenic
use gloves,glass, air filter and skin protector. Other catalysts how Fe2O3 ,
CuO or Copper Chromite are very little effective.
Typical AN composite propellant formulation :

AN     67%
AL         9%
Mg       5%
HTPB 15%
PD          4%   Potassium Dichromate or AD

The AN is a very good Oxidizers and very safe but   how can you stabilize the
phase changes ?

I am very interested in AN composites because I am working in Low Cost SRB,
I have thought in two ways the first is AN composites with low metal fuel
and other Hybrid motor, Our SRB project need 500Kg propellant with 200 ISP
or more. the KNO3+Sorbitol have a ISP 130 and a very low melting point
with a long burn time the propellant can be liquid and burn all at the time
with explosion.
any suggestion ?


=========================================================================
Date:         Thu, 26 Aug 1999 12:49:13 -0500
Reply-To:     Chemical Propulsion Research <CHEMROC@LISTSERV.UGA.EDU>
Sender:       Chemical Propulsion Research <CHEMROC@LISTSERV.UGA.EDU>
From:         Terry McCreary <terry.mccreary@MURRAYSTATE.EDU>
Subject:      Re: observation DDI 1410 Aliphatic Diisocyanate
Mime-Version: 1.0
Content-Type: text/plain; charset="us-ascii"

At 09:01 PM 8/25/99 -0700, you wrote:
>Not a chemical reaction, but atmospheric N2 appears to dissolve more readily in
>DDI than other isocyanates. Or so I was told by Scott Dixon many years ago.
>
>I found that using DDI in HTPB propellants would result in a strange "foaming"
>reaction. Scott believed that the dissolved N2 was "squeezed" out of the
polymer
>during cure. Vacuum degassing the DDI prior to mixing in the propellant seemed
>to solve the problem.

Sounds reasonable; if vacuum prior to addition solves the problem, it's
likely a dissolved gas rather than a reaction with moisture or whatever.

=========================================================================
Date:         Fri, 27 Aug 1999 00:53:13 -0400
Reply-To:     Chemical Propulsion Research <CHEMROC@LISTSERV.UGA.EDU>
Sender:       Chemical Propulsion Research <CHEMROC@LISTSERV.UGA.EDU>
From:         "James E. Lanier" <jelanier@BELLSOUTH.NET>
Subject:      AN catalysts :Ammonium Dichromate
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After a bit more experimenting, I have found that ammonium dichromate works
well in very small percentages. Finely divided, it produced good results as
a catalyst down to about 4-5 percent. This is important in that it is a
heavy, low impulse oxidizer.

Jim Lanier


=========================================================================
Date:         Sun, 12 Sep 1999 14:39:08 -0400
Reply-To:     Chemical Propulsion Research <CHEMROC@LISTSERV.UGA.EDU>
Sender:       Chemical Propulsion Research <CHEMROC@LISTSERV.UGA.EDU>
From:         "James E. Lanier" <jelanier@BELLSOUTH.NET>
Subject:      Particle Size in Polymeric Binder Systems
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    As far as particle size is concerned. Care must be taken in polymeric
binder systems if they are to have any elastomeric qualities. A particle
size of 200 microns has a surface area of 0.018 square meters/gram for a
substance with density close to AN. Compare this to 1 micron particles with
a surface area of 3.64 square meters/gram. That's a lot of area!! Because of
this, very fine particles produce a very dry mix resulting in a hard grain.
Multimodal blends are the answer here.

Jim


=========================================================================
Date:         Wed, 15 Sep 1999 09:58:09 -0500
Reply-To:     Chemical Propulsion Research <CHEMROC@LISTSERV.UGA.EDU>
Sender:       Chemical Propulsion Research <CHEMROC@LISTSERV.UGA.EDU>
From:         Terry McCreary <terry.mccreary@MURRAYSTATE.EDU>
Subject:      Re: KN instead AN
Mime-Version: 1.0
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At 11:59 PM 9/15/99 +1000, you wrote:
>people seem to be using AN instead of KN, NASA uses AN but with high
>metal loadings, ie: mag which costs heaps. Why bother when you can use a
>non-hydroscopic oxidiser like KN ?

Depends on what is needed. If high specific impulse is a requirement,
ordinarily KN will not be considered.

Here's where Propep gives a definitive answer. Run it on a mix of 80% KN,
20% and look at Isp. Then change to AN and do it again. Then change to 20%
Mg and 60% AN and see what it gives. Then play with Propep some more; it's
kinda fun.

Mg is not particularly expensive; I guess it depends on what one calls
"expensive". $10 a pound is two hours of minimum-wage work in the US and
will produce five pounds or more of high-impulse AN propellant.

P'rfesser
=========================================================================
Date:         Wed, 15 Sep 1999 11:20:59 -0400
Reply-To:     "James E. Lanier" <jelanier@bellsouth.net>
Sender:       Chemical Propulsion Research <CHEMROC@LISTSERV.UGA.EDU>
From:         "James E. Lanier" <jelanier@BELLSOUTH.NET>
Subject:      Re: KN instead AN
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AN has reasonably high specific impulse without metals. With metals, the
impulse of AN is almost as high as AP propellants. KN is an awful choice for
performance. The molecular weight of the exhaust gasses is too high. KN is
hydroscopic also, just not as much. AN gets it's high performance from low
molecular weight exhaust products. If you use metals with AN, then you have
low molecular weight and high temperatures. AN exhaust is also more
environmentally friendly.

Jim

=========================================================================

Reply-To:     Chemical Propulsion Research <CHEMROC@LISTSERV.UGA.EDU>
Sender:       Chemical Propulsion Research <CHEMROC@LISTSERV.UGA.EDU>
From:         Lawrence Teebken <Larry79054@AOL.COM>
Subject:      Re: Particle Size
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Stephen,
      From your description, you are going to end up with a solid propellant
that is going to have a lot of "void space" in it. That is, the 2-5% shellac
content is almost certainly not going to be enough to fill in all of the
empty spaces between the solid particles, even if you use a multi-modal
particle mixture. This is one of the reasons, I think, that the burn rate is
so high: the actual burning area is much more than the circular end-burning
geometric area. It is composed of the surface area of millions of small
particles. It is not inconceivable that the true burning area could be two
or more times the apparent burning area. I believe that this is one of the
reasons that zinc/sulfur (Micrograin) propellant works as well as it does.
Probably, you are also doing formulation or operating pressure modifications
to enhance burning rate, but this is also a source of increased appparent
rate.
      One of the concepts shared by the paint and propellant industries (or,
for that matter, any industry which makes use of solids dispersed within
liquids. Another example would be concrete.) is that of CPVC: Critical
Pigment Volume Concentration. Let's say that you have a tube full of a
powder that has been settled to its maximum bulk density. You might
accomplish this by vibration or tapping the tube (also known as the "tap
density") until the contents no longer settle. Depending upon the particle
shape, size, range of sizes, etc., the amount of empty space left over can
typically range anywhere from about 25% to 45%, by volume. If you have a
multi-modal mixture of particles, then some of the smaller particles
infiltrate the empty spaces between the larger particles and the void space
decreases. Studies have been done on this by a lot of different people in
diverse fields; mathematics, concrete, paint, and propellant fields come to
mind without even thinking much about it. So, you start out with this
densified powder column. Then, you start adding small amounts of liquid to
the powder. Eventually, you will get to a point at which the entire void
space will be just filled with the liquid. This is, by definition, the CPVC.
 Any concentrations of powder below this value give mixtures that also has no
void space and should become more and more flowable. Any powder
concentrations above this value give mixtures in which there is an
UNAVOIDABLE amount of void space. The mixtures will tend to become more and
more "dry" and crumbly and difficult to mix, like concrete with insufficient
water content.
     In composite propellants, the idea is to make sure that the void space
is completely filled with liquid so that all of the solid particles are
bonded in place. In order to reduce this liquid amount, because this
generally increases density and decreases viscosity, one can use multi-modal
oxidizers and/or metals. Multi-modal simply means multiple particle sizes.
It has been shown mathematically that, for spherical particles, the spaces
between the particles have a maximum opening that is about 15% of the size of
the particles. So, if you have 200 micron AP and want to use a bi-modal
mixture, then you need to use 200 X 0.15 = 30 micron particle sized AP.
Theoretically, these smaller particles will just thread their way through the
openings between the 200 micron particles without being blocked. The actual
weight of the 30 micron is quite small, as the actual volume between the 200
micron particles is also quite small. I don't have info regarding the weight
needed, but, if you study any professional formulations, you'll see that they
use a higher percentage of the smaller size than the above formula would
estimate. Partly, this is due to the fact that AP particles are usually
shaped more like potatoes than spheres and partly for other burning rate,
etc., reasons.
     So, to sum this all up, I would say that you should be aware, if you're
not already, that having such a small percentage of binder will result in a
grain that still has anywhere from 23%-43% empty airspace within it. And, if
you should add any oils in order to soften the grain, then, if you don't
substitute it for some of the shellac and simply add it to the amount of
shellac already present, then your "binder" percentage is going to increase
substantially, though probably not enough to get rid of most of the void
space. In any case, good luck with your experiments and keep the list
informed, as I know we're all interested in your progress.
Larry Teebken (larry79054@aol.com)


=========================================================================
Date:         Sat, 18 Sep 1999 01:35:59 +0400
Reply-To:     Chemical Propulsion Research <CHEMROC@LISTSERV.UGA.EDU>
Sender:       Chemical Propulsion Research <CHEMROC@LISTSERV.UGA.EDU>
From:         Serge Pipko <spas@AKCECC.KIEV.UA>
Subject:      LiClO4 homogeneous solid propellant
Comments: To: arocket <arocket@nmt.edu>
MIME-Version: 1.0
Content-Type: text/plain; charset="koi8-r"
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Hi All,

It became more and more clear for me that I have inherent fancy for making
exotic propellants. One of ideas that never leave me in peace is to make
homogeneous solid propellant with oxidizer and fuel completely solvable in
each other. I tried to dissolve AP in various potential fuels, such as
sucrose, sorbitol, polyethyleneglicol, triazole, benzotriazole,
dimethylsulfoxide, etc. at ambient temperature and up to 120úC. (to my
surprise, AP is stable at that temperature) Neither of these mixtures was
gomogeneous or at least pourable.

BUT LiClO4 !

The first attempt was successful. I mix 70% LiClO4 / 30%
epoxy+curative(maleic anhydride - for high temperature processing), heat to
150úC and mixture became clear liquid (well, brown liquid), all bubbles
readily released. After heating 2 hours at 150úC mixture was still liquid
and after cooling I had hard plastic-like mass.

Summary of some test results:

Thermal stability
I put small piece (~0.1g) on the top of hot plate (black iron surface) and
turn on power. At 130úC propellant melted, at 180úC began to bubble, at
230úC became dark-brown solid porous mass. I heat it up to 290úC, but it
don't ignited. I concluded that preparation of propellant at 150úC is
reasonably safe.

Burn test
I poured hot propellant in paper tube (ID=9mm) and lit it after cooling. It
burned vigorously, ambient pressure regression was 2 mm/s. It is comparable
to what I have with uncatalised AP/epoxy 80/20 (2.7 mm/s). Flame color was
not as red as I expected.

Performance prediction
PROPEP gives maximum Isp=233 for LiClO4/ SHELL EPON 815 78%/22%. (D=
0.06993 LB/CU-IN OR 1.9358 GM/CC).
70/30 mix has Isp=221. (D= 0.06534 LB/CU-IN OR 1.8087 GM/CC)

For AP/ SHELL EPON 815 maximum Isp=249 (87%/13%). (D= 0.06422 LB/CU-IN OR
1.7777 GM/CC).
80/20 mixture has Isp=238. (D= 0.06152 LB/CU-IN OR 1.7030 GM/CC).

Does anyone have thoughts about possible pressure exponent for this
propellant?

Thereby, LiClO4/epoxy propellant has advantages:
- very simple preparation. Finished grain may be prepared during 3 hours.
- high performance (possible).
- high density.

It is expensive, however.

Serge Pipko

=========================================================================
Date:         Sat, 18 Sep 1999 12:15:48 +1000
Reply-To:     Chemical Propulsion Research <CHEMROC@LISTSERV.UGA.EDU>
Sender:       Chemical Propulsion Research <CHEMROC@LISTSERV.UGA.EDU>
From:         "Stephen J. Holden" <rocket@ACEPIA.NET.AU>
Subject:      Re: Particle Size
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Lawrence,
Again, thanks for the insight into the porosity problem. It is always useful to
here other peoples opinions and knowledge applied to the problems we have. It
helps me in the formulation of new ideas, so it is well appreciated.

You may be surprised that we are getting less than 5% porosity with quite a low
loading pressure of about 6 MPa. The level of porosity is approx. equivalent to
the amount of alcohol we add. So for 5% porosity we use about 5% alcohol. This
can be evaluated by comparing the theoretical density (all the ingredients
completely packed up without voids) to the measured density. We also find that at
5% alcohol and 6MPa loading pressure, the binder is on the point of being
squeezed out of the propellant. From this you can see that if we were to add less
alcohol we would need a higher loading pressure to compact the propellant.
Loading under pressure makes all the difference with the reduction in the
porosity level.

One should not try to apply composite propellant ideas to this propellant as it
is completely different. Loading under pressure changes the equation altogether
and improves the propellant properties in a remarkable way. If one were to simply
mix the binder into the solid ingredients and allow it to dry (much like a
composite propellant) the propellant would simply break in the hands and would
most likely explode under pressure.

I do not know what the particle distribution would be for the propellant
ingredients since they are all milled together. I do know that you must reduce
the particle size to extremely fine sizes (we may attempt to measure the average
particle size) for efficient combustion. We have determined this by milling a
batch of 120 gm and taking out small samples at different times in the milling
and burning them. We find that at at about 8 hr the mixture only sparingly burns,
at 24 hr it does burn. We may also find that when the silicon powder is milled
and mixed into the other ingredients as fine as it is, that we may be able to use
quite large percentages of silicon and boost the Isp to over 240 s. Basically,
the propellant is like BP in the way it is processed. BP relies on intimate
mixing for efficient and rapid burning. This propellant is much like BP but with
a much higher performance.

It is not certain if micrograin burning will occur at ~5% porosity. Because of
the fine particle size, it does burn at a high rate anyway. I think that we will
find that there is a pressure at which micrograin burning starts to set in at a
certain levels of porosity. We will see............

All the best..Stephen.


To ALL:
with regards to Serge's LiClO4 homogeneous solid propellant binders etc.

Serge,

I read with interest your propellant experiments, and some comments
regarding solubilities of various binders in solvent. Solvent, polymer
interactions are of interest to me, as is rocketry. I go back many years
with rocketry and I made some rather large zinc-sulfur rockets.
I did not have the know-how or the means to experiment with higher
specific impulse propellants. But, my interests seem to be merging.
I have a freeware solvent polymer program on the world wide web, that
might be useful in estimating binder solvent solubilities. For example,
you did mention EPON 815. I have many
polymers in the provided database, hydroxyl terminated polybutadiene
etc. If you would like to obtain this program, the link provided should
get you there. If not try: www.hotfiles.com (ZDNET'S file section) pick
search options and search by the author name: LAW or program name
CO-SOLVE-IT!
Download the program into a subdirectory that you create for the
compressed file. Unpack the compressed file using PKWARES (also found
on
ZDNET) and use PKUNZIP to expand the files. The main program is started
from within your subdirectory by typing the command STARTUP (press
enter).
This software is menu driven, a documentation file in the WORDPERFECT
5.1 format is included,.. the documentation (Manual) is called
COSOLVET.WP
Operational and solubility theory can be found in the documentation.
Various help files are also found within each program module. The
program is a DOS type program and needs about 540 KB of DOS
memory (conventional memory) to run well.
I hope this software is some help to you, and others with the same
interests.



http://hotfiles.zdnet.com/cgi-bin/texis/swlib/hotfiles/info.html?fcode=000NEC&b=
--
warm regards,
Michael P. (mike) Law

=========================================================================
Date:         Tue, 21 Sep 1999 07:50:52 +1000
Reply-To:     Chemical Propulsion Research <CHEMROC@LISTSERV.UGA.EDU>
Sender:       Chemical Propulsion Research <CHEMROC@LISTSERV.UGA.EDU>
From:         "Stephen J. Holden" <rocket@ACEPIA.NET.AU>
Subject:      Re: LiClO4 homogeneous solid propellant
MIME-Version: 1.0
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Serge,
It is possible to measure a and n without a strand burner. Form your propellant
into neutral burning BATES grain and a small motor. Measure the burn time by
visual observation (using a video camera) and calculate the mass flow rate.
Calculate C-Star using Propep.
Then calculate Pc = mass flow * (C-Star) / (Throat Area * Accel. Due to Gravity)

All the best...Stephen.

=========================================================================
Date:         Wed, 22 Sep 1999 14:35:06 -0500
Reply-To:     Chemical Propulsion Research <CHEMROC@LISTSERV.UGA.EDU>
Sender:       Chemical Propulsion Research <CHEMROC@LISTSERV.UGA.EDU>
From:         Terry McCreary <terry.mccreary@MURRAYSTATE.EDU>
Subject:      Simple propellant
Mime-Version: 1.0
Content-Type: text/plain; charset="us-ascii"

Well, as long as we're posting results...here's from the simple PBAN
propellant. Composition:

16.4% PBAN (polybutadiene acrylic acid acrylonitrile)
3.6% DER331 epoxy resin
0.2% carbon black
79.8% 200 micron AP

Hand mixed, no vacuum processing, cures at 140 F in about 2-4 days.    Density
is about 0.054 lb/in^3 (theoretical is 0.058).

This weekend I fired six 29mm 3-grain motors (0.93" dia x 0.375" core x 1.5"
long grains) with graphite nozzles. Thrust was measured, chamber pressure
calculated from thrust, plotted log (burn rate) vs. log (chamber pressure).

Burn rate coefficient = a = 0.033
Burn rate exponent = n = 0.335
Correlation coefficient = 0.94 = fairly straight but not great.

Note: the motors were all rather regressive, so there's undoubtedly some
error in the calculated values; I used average burn rate and average chamber
pressure. That's the disadvantage of Bates grains vs. endburners for
characterisation...

P'rfesser


=========================================================================
Date:         Sun, 10 Oct 1999 02:47:46 -0400
Reply-To:     tbinford@frontiernet.net
Sender:       Chemical Propulsion Research <CHEMROC@LISTSERV.UGA.EDU>
From:         Tom Binford <tbinford@FRONTIERNET.NET>
Subject:      Re: Core Drilling Ti containing AP/HTPB propellant
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John Lyngdal wrote:
>
> Time for an update. After weighing all the cautioning comments, I decided to
> drill the cores into the grain. I donned my safety gear and positioned fire
> gear just in case there was an incident. The drilling operation took place
> at 125 RPM using a sharp new 1/2" bit. The propellant cut easily and little
> dusting of the AP was apparent. The bit was backed out every 1/2" or so, to
> clear out the cut propellant. After the grain was to about one-half the
> length, the grain was reversed to facilitate the removal of the cut
> propellant. I bored 6 38mm BATES grains without incident, but was sweating
> the whole time. Next time I'm going to use a Teflon mandrel.
>

Note that cast core grains are much harder to ignite. Make sure your
igniter produces plenty of heat.

Tom

=========================================================================
Date:         Sun, 10 Oct 1999 07:00:18 -0600
Reply-To:     Chemical Propulsion Research <CHEMROC@LISTSERV.UGA.EDU>
Sender:       Chemical Propulsion Research <CHEMROC@LISTSERV.UGA.EDU>
From:         Brian Kosko <bkosko@FLASH.NET>
Subject:      Re: Core Drilling Ti containing AP/HTPB propellant
MIME-Version: 1.0
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John,

    A suggestion instead of a teflon mandrel. We tried a variety of
mandrels, including pure teflon rods. The one that worked best was an
aluminum rod covered with teflon tape. The problem with the teflon rod is
that it isn't rigid enough. You really have to wrestle the mandrels out of
the grains. With the aluminum rods, we drilled a hole near the top so that a
screwdriver could be inserted. This has worked for single grains up to the
54mm 1706ns size.


Brian

=========================================================================
Date:         Sun, 10 Oct 1999 20:40:38 -0600
Reply-To:     Chemical Propulsion Research <CHEMROC@LISTSERV.UGA.EDU>
Sender:       Chemical Propulsion Research <CHEMROC@LISTSERV.UGA.EDU>
From:         Brian Kosko <bkosko@FLASH.NET>
Subject:      Re: Core Drilling Ti containing AP/HTPB propellant
MIME-Version: 1.0
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It's regular tape, just put the sticky side on the rod. It's not the
plumbing kind. I get it from Firefox and find it useful for lots of rocket
stuff. I have sizes from .5in to 4 in.


Brian
-----Original Message-----
From: bruce johnson <brucej@ALPHALINK.COM.AU>
To: CHEMROC@LISTSERV.UGA.EDU <CHEMROC@LISTSERV.UGA.EDU>
Date: Sunday, October 10, 1999 5:27 PM
Subject: Re: Core Drilling Ti containing AP/HTPB propellant
>silly question but how did you get the teflon tape
>to stick to the al rod ?
>

=========================================================================
Date:         Sun, 14 Nov 1999 03:41:31 -0000
Reply-To:     Chemical Propulsion Research <CHEMROC@LISTSERV.UGA.EDU>
Sender:       Chemical Propulsion Research <CHEMROC@LISTSERV.UGA.EDU>
From:         "Michael." <d53286bg@IOL.IE>
Subject:      Re: red colored flame AP propellant
MIME-Version: 1.0
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----------
> From: Brian Kosko <bkosko@FLASH.NET>
>
> Date: Wednesday, September 22, 1999 11:27 AM
> Subject: Re: red colored flame AP propellant
>
>
> >> I just flew my first motor [38mm, 9.5 inch long] bates grain using
> >> AP 400 61%
> >> Mg 325 5%
> >> SN 10%
> >> SC 5%
>

Hello all,

Brian wrote the above some time ago.

Is the AP 400 Ammonium Perchlorate with an average partical diameter of 400 micro meters?
ie. 310 mesh (about).
What is the partical distribution in AP of this specification or do you know.
Why does Ammonium Perchlorate always seem to be used in such large partical sizes.
Wouldent finer partical sized give faster burn rates. Has anyone any formulas for ball
milled Ammomium Perchlorate, is it safe to ball mill Ammonium Perchlorate.

Do formulas using, say, K Perchlorate, use such large partical sizes.

Perhaps it's for 'pourability'?

Michael,
=========================================================================
Date:         Sun, 14 Nov 1999 13:03:07 -0600
Reply-To:     Chemical Propulsion Research <CHEMROC@LISTSERV.UGA.EDU>
Sender:       Chemical Propulsion Research <CHEMROC@LISTSERV.UGA.EDU>
From:         Terry McCreary <terry.mccreary@MURRAYSTATE.EDU>
Subject:      Re: red colored flame AP propellant
Mime-Version: 1.0
Content-Type: text/plain; charset="us-ascii"

>Is the AP 400 Ammonium Perchlorate with an average partical diameter of 400
micro meters?
>ie. 310 mesh (about).

Presumeably, yes.

>What is the partical distribution in AP of this specification or do you know.

It should be a very narrow distribution, since the material is made to this
specific size. I have no data on actual distribution of sizes.

>Why does Ammonium Perchlorate always   seem to be used in such large
partical sizes.
>Wouldent finer partical sized give faster burn rates.

Yes, finer material would give higher burn rate. It would also make the
mixture extremely thick, and may tend to increase the burn rate exponent
very slightly (according to the literature). Unless there is a pressing
need for a burn rate higher than about 0.35" per second, the 200 micron AP
seems to be adequate.


>Do formulas using, say, K Perchlorate, use such large partical sizes.

Not ordinarily. To the best of my knowledge, KP is not available in
atomized form. I think the burn rate of KP propellant is more dependent on
particle size than is AP propellant. In any event, most workers making
Bates-type motors or similar will use AP. It's more conducive to success.

P'rfesser


=========================================================================
Date:         Tue, 16 Nov 1999 08:37:27 -0600
Reply-To:     Chemical Propulsion Research <CHEMROC@LISTSERV.UGA.EDU>
Sender:       Chemical Propulsion Research <CHEMROC@LISTSERV.UGA.EDU>
From:         Brian Kosko <bkosko@FLASH.NET>
Organization: FlashNet Communications
Subject:      Re: burn rate enhancers
MIME-Version: 1.0
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On Mon Nov 15 22:14:22 1999, Chemical Propulsion Research
<CHEMROC@LISTSERV.UGA.EDU> wrote:
We've successfully used both cupric oxide and ferric oxide. Smaller AP also
does a good job.

    Brian
> What are some good burn rate enhancers for ammonium perchlorate? Preferably
these
> enhancers will speed up the burn rate with a low loss in ISP.
>
> Thanks,
Dak

=========================================================================
Date:         Tue, 16 Nov 1999 10:01:08 -0600
Reply-To:     Chemical Propulsion Research <CHEMROC@LISTSERV.UGA.EDU>
Sender:       Chemical Propulsion Research <CHEMROC@LISTSERV.UGA.EDU>
From:         Terry McCreary <terry.mccreary@MURRAYSTATE.EDU>
Subject:      Re: burn rate enhancers
Mime-Version: 1.0
Content-Type: text/plain; charset="us-ascii"

At 09:14 PM 11/15/1999 -0700, you wrote:
>What are some good burn rate enhancers for ammonium perchlorate? Preferably
these enhancers will speed up the burn rate with a low loss in ISP.

Most transition metal oxides can act as burn rate catalysts. Oxides of
iron, chromium, manganese, copper, have all been used. Magnesium oxide too.
Copper chromite is reported to be one of the best catalysts; it doesn't
increase burn rate much more than the others, but only requires a fraction
of a percent to do so.

The loss in Isp by addition of a percent of burn rate catalyst is trivial.
A propellant that produces Isp=240 w/o the catalyst might produce Isp=238 by
substituting 1% Fe2O3 for part of the AP.
P'rfesser

=========================================================================
Date:         Tue, 16 Nov 1999 08:43:12 -0800
Reply-To:     Chemical Propulsion Research <CHEMROC@LISTSERV.UGA.EDU>
Sender:       Chemical Propulsion Research <CHEMROC@LISTSERV.UGA.EDU>
From:         John Lyngdal <john.w.lyngdal@EXGATE.TEK.COM>
Subject:      Re: burn rate enhancers
MIME-Version: 1.0
Content-Type: text/plain

I did an experiment burning a motor using 200 um AP and SrNO3 with and
without 0.2% red iron oxide. Both motors consisted of 3 bates grains 2.4" in
diameter, 0.75" port, and burned at a KN of 210. The motor with 0.2% Fe2O3
burned in 4.1 seconds. A second fuel load without the iron oxide, but with
0.1% lampblack added burned for 5.8 seconds.

The Shuttle SRB's use iron oxide as a burn rate catalysis, leading one to
believe that it is optimum agent from a performance standpoint.


John

=========================================================================
Date:         Tue, 16 Nov 1999 16:06:35 -0600
Reply-To:     Chemical Propulsion Research <CHEMROC@LISTSERV.UGA.EDU>
Sender:       Chemical Propulsion Research <CHEMROC@LISTSERV.UGA.EDU>
From:         garym <garym@IPA.NET>
Subject:      Re: burn rate enhancers
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              boundary="------------1C069AB26F5972074CB38DB9"

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copper chromite,max 3%,chromium oxide.

Connie Steiert wrote:

> What are some good burn rate enhancers for ammonium perchlorate?
> Preferably these enhancers will speed up the burn rate with a low loss
> in ISP. Thanks,Dak


=========================================================================
Date:         Wed, 17 Nov 1999 19:17:01 -0800
Reply-To:     rockitman@sprintmail.com
Sender:       Chemical Propulsion Research <CHEMROC@LISTSERV.UGA.EDU>
From:         Anthony Colette <rockitman@SPRINTMAIL.COM>
Subject:      Re: burn rate enhancers
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> Copper chromite is reported to be one of the best catalysts; it doesn't
> increase burn rate much more than the others, but only requires a fraction
> of a percent to do so.

I think iron oxide actually increases the burn rate a tad bit more than copper
chromite but the outstanding advantage of copper chromite is that it actually
supresses the burn rate exponent.
Where as iron oxide increases the burn rate exponent.
Use 2% copper chromite with 5% cattocene and 15% Al, and you can get 2-4 inches
per second @ 1000 psi, with exponents as low as 0.2.

GAP binder can increase the burn rate to 6-8 inches per second.
Anthony


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Date:         Thu, 18 Nov 1999 09:16:14 -0600
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>I'll let a chemist describe it.   My reference's are at home.

Catocene and butylferrocene are both substituted ferrocenes. (ferrocene =
(C5H5)2Fe) Both are liquid at room temperature, which undoubtedly
contributes to their activity as burn rate catalysts.


>> > I think iron oxide actually increases the burn rate a tad bit more than
copper
>> > chromite but the outstanding advantage of copper chromite is that it
actually
>> > supresses the burn rate exponent.
>> > Where as iron oxide increases the burn rate exponent.

>From Rumbel, in "Propellants Manufacture, Hazards, and Testing", p 55:

"A 10% increase [in burn rate at 1000 psi] is obtained by adding 2% ferric
oxide or 1% chromic oxide, magnesium carbonate, or magnesium oxide...a 20%
increase is obtained by adding 1% Prussian blue or 2% of a mixture of equal
parts copper oxide and magnesium oxide...As little as 0.2% [copper chromite]
increases the burning rate 25%...it has a persistent tendency to lower the
pressure exponent"

Interesting graph therein shows a knee in the burn rate vs. % added for
copper chromite, at 0.2%. (no CC, 0.44"/s; 0.2% gives 0.54"/s; 1% gives
0.57"/s; 2% gives 0.63"/s. More than 2% CC drops the burn rate.

The CC was from Harshaw Chemical Co., number 0202P, whatever that is.

That being said, the data is for PVC plastisol propellant, which undoubtedly
differs somewhat from HTPB propellant. And somewhere I have a reference
that says that *both* Fe2O3 and CC are most effective -- one at higher
pressure, one at lower pressure, I forget which is which (probly Fe2O3 at
higher pressure).

So, no doubt that Anthony is correct, that someone (many someones?) has
reported higher burning rates for Fe2O3 than for CuO. I'd bet that the type
of Fe2O3 has a great deal to do with it, as I've personally seen
significantly different burn rates for this catalyst, depending on the source.

P'rfesser
"In my extensive experience, the most effective burn rate catalyst is lotsa
bubbles in the propellant" :-)


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Date:         Sat, 20 Nov 1999 14:09:18 +0300
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From:         Serge Pipko <spas@AKCECC.KIEV.UA>
Subject:      Re: burn rate enhancers
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If I understand correct, burn rate catalysts can increase rate of the
following steps of propellant's burning:

1. decomposition of oxidizer;
2. decomposition of binder;
3. reactions between the products of 1 and 2.

In what steps catalyst's role is more important ?     Is there difference
between AP and AN propellants ?

Serge Pipko

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Date:         Sun, 28 Nov 1999 07:27:25 -0600
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And here's my two pence:

There are two kinds of catalysts often used in propellant work. A cure
catalyst increases the rate of cure; Larry refers to this below. For HTPB
systems, cure catalysts include triphenylbismuth, dibutyltin dilaurate,
cobalt octoate, and many other transition metal-organic compounds.

A burn rate catalyst increases the rate of burning.     Most common here are
the transition metal oxides.

P'rfesser

At 12:02 AM 11/25/1999 EST, you wrote:
>Brian,
>     Something needs to be explained, here. When one adds a multi-functional
>ingredient, such as castor oil or glycerol or diethylenetriamine, etc., there
>is, in fact, an effect not unlike catalysis. These multi-functional (i.e.,
>having more than 1 or 2 active sites per molecule) compounds can have the
>effect of increasing the rate of the gelling and/or curing reactions, thereby
>lowering the amount of time it takes the mixture to gel or cure. This
>happens simply because there are more sites available (called the 'mass
>action effect') and, sometimes as with nitrogen-containing compounds
>(amines), by virtue of their high reactivity. The rate-increasing effect can
>be as dramatic as those of 'real catalysts'. If you were to add a
>tri-functional compound, like glycerol, the reaction rate would be greatly
>increased in most systems. Admittedly, 0.5% castor oil is not a large
>concentration, but do not ignore that its multi-functional nature might still
>have a significant effect. Hope this helps.
>Larry Teebken (larry79054@aol.com)

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Date:         Sun, 28 Nov 1999 13:39:41 -0500
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From:         "James E. Lanier" <jelanier@HOME.COM>
Subject:      Re: Cheap propellants
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    Actually, ammonium nitrate is a very good oxidizer for composite =
propellants. There is a phase stability problem, so a phase stabilized =
AN should be used. (Preferably a zinc oxide based stabilizer with an AP =
or Ammonium sulfate counter-ion). CP technologies sells PSAN. AN =
propellants require a catalyst if they are to be used effectively with =
polymeric binders. The best to use is Magnesium powder. It serves as a =
burn rate catalyst as well as a thermic component. Magnesium reacts with =
molten AN, making ignition very easy (coat your magnesium in binder =
first before adding AN!). I have also used Ammonium Dichromate as a =
catalyst with AN. It works well even with polymeric binders. If you are =
considering a true composite propellant with AN, one or both of these =
are essential ingredients IMHO.
    Sodium chlorate?...I don't think of chlorates as being particularly =
safe. Some of the pyrotechnicians can tell you about possible reactions =
resulting in unwanted ignition etc. I have used Sodium Perchlorate with =
pretty good results. Hydroscopicity is a problem though (as with AN). If =
you wish to use a perchlorate, AP is the tried and true oxidizer for =
composites and it is readily available in various particle sizes..

Jim


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Date:         Mon, 29 Nov 1999 16:38:04 -0600
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> One of the problems was low burning rates.How much would I get with both
Mg and catalysts?

No significant improvement over Mg alone. At least that's been my
experience. When Mg is used, the "rate determining step" is no longer
decomposition of the AN, and speeding that decomposition does little or no good.

> Doesn't the stuff (AN) has to be superdry before using it? I had
difficulties igniting it because of the water content.

It should be very dry, if for no other reason that the moisture will cause
curing problems with isocyanates. Once cured, just keep the
propellant/motor in an airtight sealed container with a bit of desiccant.

P'rfesser

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Date:         Wed, 1 Dec 1999 22:49:12 +1100
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From:         "Stephen J. Holden" <rocket@ACEPIA.NET.AU>
Subject:      Re: AN eutectics experiments
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Serge,
It depends on the igniterbility of the AN propellants that you are
developing. I would assume that the propellant may be reasonably difficult to
ignite. You may need a composition that burns hot and perhaps raises the
pressure within the chamber. A mixture of magnesium powder, potassium nitrate
and a binder such as epoxy or HTPB or shellac in absolute alcohol would do. I
would use an electric igniter dipped into this type of mixture. The igniter
would need to burn long enough to cause ignition. You may need to vary the
burn rate by changing the composition and igniter composition mass until you
get an efficient start. All the best...Stephen


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Date:         Wed, 1 Dec 1999 07:02:30 -0500
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Subject:      Re: AN eutectics experiments
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>pressure within the chamber. A mixture of magnesium powder, potassium
nitrate
>and a binder such as epoxy or HTPB or shellac in absolute alcohol would do.
I


You don't want to use ANY potassium nitrate in AN/Magnesium compositions. It
hurts performance and ignitability is not a problem with AN/Magnesium. You
can light it with a match!

Jim

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Date:         Fri, 3 Dec 1999 14:40:15 -0600
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From:         Terry McCreary <terry.mccreary@MURRAYSTATE.EDU>
Subject:      Re: AN eutectics experiments
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At 09:33 PM 12/3/1999 +0300, you wrote:

>I am now at the stage of drilling nozzles in test motor for eutectic-starch
>propellant. What Kn would be right for the first attempt ?

A suggestion: burn the mixture in the open and record the approximate burn
rate. Compare it to sucrose-potassium nitrate mixture. If it burns slower
than sucrose-potassium nitrate, use a higher Kn than that mixture would use.
Burns faster, reduce the Kn.

Only use this method if no one comes up with a better one...

P'rfesser

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Date:         Sat, 18 Dec 1999 06:24:31 -0600
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Sender:       Chemical Propulsion Research <CHEMROC@LISTSERV.UGA.EDU>
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At 07:04 PM 12/17/1999 -0700, you wrote:
>Then compare these propellants against eachother. Keep in mind the ammonium
nitrate propellants burn slowly, the ammonium perchlorate propellants burn
much more quickly, and the potassium perchlorate propellants I believe
(correct me if I'm wrong here) burn somewhere in-between.

Typical burn rates for experimentalist propellants at 600 psi might be:

AN   propellant w/Mg: 0.1 in/s
AP   propellant w/o burn rate catalyst: 0.2 in/s
AP   propellant w/burn rate catalyst: 0.3 in/s
KP   propellant: 0.6 in/s

Potassium perchlorate is much more sensitive to chamber pressure than is AP
or AN (higher burn rate exponent). AP is generally easiest for the
beginning experimentalist. Low exponent and easily ignited.

P'rfesser

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Date:         Wed, 22 Dec 1999 18:38:44 EST
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From:         Lawrence Teebken <Larry79054@AOL.COM>
Subject:      Re: Polyurethanes
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Bert,
     By definition, polyurethanes are compounds formed by the reaction of
isocyanates with compounds having hydroxyl groups (OH) attached to them. OH
groups are the groups found on such things as alcohols, glycols, etc. The
resulting reaction product is known as a urethane. When you have a whole lot
of these groups strung out in a row or in a 3-D network, you then have a poly
 (meaning "many') urethane. Since HTPB has hydroxyl groups on its molecules,
it forms urethanes with isocyanates. Since the HTPB chain length is long,
and since it can be cross-linked to form a 3-D network, it therefore becomes
a polyurethane. Since HTPB has more than one OH group (typically, between 2
and 3 OH groups) per molecule, it is known as a polyol, that is, poly meaning
many and ol from alcohOL.
     I believe that the types of materials you are thinking about are a type
of polyol (i.e., having "many" OH groups) known as polyoxypropylene glycols
or triols, etc. Note that the poly means many, the oxy means that there are
oxygen atoms distributed throughout the length of the chain and the propylene
means that the basic "backbone" of the compound is made from propylene, an
organic compound having 3 carbon atoms in a straight row. The term glycol
(or diol) means that each molecule has two OH groups on it, the term triol
means that each molecule has 3 OH groups, on it, and so forth.
     The reason that these non-HTPB-type polyurethanes tend to be more
flexible is that, on a molecular level, the various parts of the molecule can
rotate around themselves into different configurations relatively easily.
This is because the molecular bonds that hold everything together are,
mostly, single bonds, like a single stick holding two balls together. It's
easy, relatively, for the balls to rotate around the stick. But, HTPB is a
molecule that is comprised of several carbon atoms in a row, some held
together by single bonds and some held together by double bonds. The carbons
connected by single bonds would normally be able to rotate relatively easily
if it were not for the fact that each is connected to OTHER carbon atoms by
double bonds. Imagine the two balls in our example being held together by
two sticks, side by side, fitting into holes in each ball that are right next
to each other. You can see that, if you try to rotate such a configuration,
the two sticks tend to become crossed and you are unable to get much rotation
at all. (The actual bonds are probably a little curved away from each other,
which tends to give a little more "wiggle room" than this simplified view
might predict, but the result is the same.)    This makes the balls and
sticks "stiffer" and, likewise, the same is true of the HTPB molecule.
     Finally, though polyoxypropylene polyols have been used in the past to
make propellants, there are two other problems that makes them less than
desirable. Remember I said earlier that they have, typically, oxygen atoms
dispersed throughout the chain. These oxygen atoms have the undesirable
tendency to attract and hold onto moisture. So, the resins must by carefully
and thoroughly dried (to less than 0.01% by weight!) of moisture content and
stored in a completely dry environment prior to use. Furthermore, during
mixing, they have a tendency to pick up a little moisture from the,
inevitable, small amount of atmospheric air that gets whipped into the
mixture. So, mixing should be done under vacuum or dry nitrogen. Finally,
even after curing, over months or years, these kinds of propellants can
attract moisture into the interior of the propellant (all plastics, rubbers,
etc., are permeable to various gases; some gases get inside more quickly than
others), and thus alter somewhat the mechanical properties, usually for the
worse. For these, and I'm sure other, reasons, HTPB and similar types of
propellant binders were long ago considered to be the best choice for
propellant purposes. The second problem is probably of less concern to you.
Since some of the carbon atoms in polyoxypropylene polyols have oxygens
already attached to them (that is, you could say that they are already
"oxidized"), they are now not available to be oxidized by the solid
propellant oxidizer. This lowers the performance somewhat.
     Now, after having said all of that, I would tell you that it is
certainly worth experimenting with these compounds. But, be aware that
moisture reacts with isocyanates, forming carbon dioxide gas, and causes the
curing material to "puff up" in the mildest cases or become a huge foamed-up
mess in the worst cases! Isocyanates must be kept in a dry environment, as
well, and the airspace in its container must be purged with some sort of dry
gas before re-capping the container. Dry nitrogen is usually used, but dry
air or perhaps even some of those computer dusting gases could be used. Just
remember to introduce the gas of your choice gently so as to fill the
airspace up from the bottom, thereby displacing the atmospheric air upwards
and outwards. Good Luck!
Larry Teebken (larry79054@aol.com)

In a message dated 12/22/99 2:06:36 PM Pacific Standard Time,
Bert.Kimpe@VT4.NET writes:

<< Hello,
 does anyone knows what polyurethane plastic (PUR) is made of? I know it's
polymerisized with di-isocyanates. I would like to compare it with HTPB
because as far an I know PUR is a general name for a group of elastomeric
plastics and HTPB is in this group. I can buy what's called PUR plastic wich
is much cheaper and very very flexible.
 Thanks.
 Greetings
 Bert Kimpe
  >>

=========================================================================
Date:         Sun, 26 Dec 1999 08:57:38 -0700
Reply-To:     jfrost@verinet.com
Sender:       Chemical Propulsion Research <CHEMROC@LISTSERV.UGA.EDU>
From:         Jack Frost <jfrost@VERINET.COM>
Organization: Pawnee Aerospace Sciences Association
Subject:      self-extinguishing propellant: AP with C - H - O fuel
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Has any one seen / explain self-extinguishing strand burn behavior as
in:
66% AP with 33% Sorbitol fuel?

A strand burns about 1 mm per sec for 2 seconds with a uniform, robust
orange flame
at 12 psi atmospheric, 20C ambient.
It always self extinguishes.
Ditto at 10C ambient, but extinguishes more quickly.

Very repeatable.

Independent of cure cycle or maturity of the strand.

It appears as if a burning boundary exixts at the "solid /
almost-sagging-plastic-propellant boundary",
but the orange flame exits further out, maybe 0.2 mm from the first
boundary.

The burning CAN continue at the first boundary for the following
condition:

Additional catalysts like Fe2O3 with KNO3 do not seem to effect the self
extinquishing phenonoma, other than promoting the surface burn effect
(after the flame is extinguished) which progresses about as slowly, and
with a slight sputtering sound,   producing a whitish slag.

When the orange flame is present, there is virtually little, if any,
smoke.

jfrost


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Date:         Tue, 28 Dec 1999 04:51:38 -0800
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> P.S. Does anyone know the approximate OH of 143L? It's from Firefox, but
it doesn't say the OH, equivalent weight, fuctionality, or molecular weight.
If you can supply the 1st, 2nd, or 3rd and 4th, I would be happy.

I don't have specifics for 143L, but it is an MDI mixture (4,
4'-methylenebis(phenyl isocyanate). MDI itself is CH2(C6H4NCO)2, FW=250,
equivalent weight = 125, functionality= 2. Most stuff labeled "MDI" is a
mixture of difunctional and trifunctional compounds, plus probably a little
monofunctional compound (reactive diluent) for lowered viscosity. Anyway,
the numbers given above may be approximations only.

P'rfesser

				
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