MADISON CHEMICAL INDUSTRIES INC.
                                                APPLICATION INSTRUCTION BULLETIN
                                                                 GEMTHANE® MG-201™
                                                                                 Form No. AIB 2008-12
                                                                                  Version 3, June 2009

GemThane MG-201 is a solvent free, 1:1 mixing ratio, two-component epoxy primer sealer. It is slow
setting, solvent-free and has medium viscosity, all of which makes for easy paint-like application. It
has the unique advantage of being high performance (e.g. finished product is immersible) and low-
odour at the same time. MG-201 is specifically formulated for superior recoatability (excellent
adhesion to subsequent topcoat) and extremely high adhesion to many substrates. Another property
of GemThane MG-201 is its ability to seal troublesome surfaces such as concrete, galvanized steel
and ductile iron, allowing a pinhole free finish. On wood, it penetrates deeply, providing a secure
bond for the topcoat of your choice.

GemThane MG-201 is not a paint. It consists of resins that will react with humidity and moisture. Care
should be taken in handling of coating containers to prevent puncture, freezing, unnecessary opening
or other action that may lead to product contamination. Material should be stored between 21oC
(70°F) and 32oC (90°F). DO NOT FREEZE or expose product to temperatures below 10 oC. Use
product within 12 months of receiving. GemThane MG-201 is a pure epoxy resin. Please note that
this product, particularly the “A” side, may crystallize when stored below the recommended storage
temperature range. Should this occur, gently heat the product and stir. This will re-disperse the
crystals and the product will be suitable for use.

1)     Ensure that the surface is clean, dry and uncontaminated. Dew or condensation or extremely
       high humidity (over 85%) will impair adhesion and cure of product. Therefore, proceed only if
       the substrate temperature is more than 3°C (5°F) above the dew point temperature at all times
       (internet and weather channel can provide this information). After using the appropriate
       surface preparation method described below, clean surface by vacuuming or by wiping with a
       cloth dampened with GemThane VR-4 Reducer.
2)     On new wood, make sure moisture content is below 12%. Lightly but thoroughly sand surface
       with 80 to 100 grit sandpaper.
       On old wood, painted or not, pressure wash at 1,000 psi or greater prior to sanding. Mix or
       inject GemBond Surface Conditioner or an industrial degreaser into the water in order to
       remove embedded dirt. Alternatively remove grease and other contaminants with VR-4
       Reducer, then scrub surface of wood thoroughly with hot, soapy water and allow to dry. After
       cleaning as above, sand thoroughly (80 to 100 grit sandpaper) and wipe clean with VR-4
       Reducer to eliminate dust before proceeding. Do not coat green or damp wood.
                         GEMTHANE®, a division of MADISON CHEMICAL INDUSTRIES INC.
                              490 McGeachie Drive, Milton, Ontario, Canada, L9T 3Y5
                 Tel: (905) 878 - 8863    Fax: (905) 878 - 1449     E-mail:
3)   For concrete- atmospheric service, concrete must be fully cured. The use of GemBond will
     eliminate the need to sandblast or acid etch the concrete. After removing “spent” GemBond
     by power wash or floor scrubber, allow surface to dry at which time it is ready to be coated.
     Depending on porosity, concrete may need to be filled. Where bug-eyes exist, Madison
     PrepCrete, a cementitious patching compound, should be used to fill same before proceeding
     For rough or pitted concrete floors, a self-leveling base coat, such as GemThane MG-220 may
     be used. Vertical surfaces such as poured-in-place concrete and concrete block can usually
     be coated as-is; however, for a pinhole-free result, fill bug-eyes with a cementitious grout such
     as Madison PrepCrete, let dry for 2 or more days and then coat the entire surface with
     GemThane MG-201 or heavier-bodied GemThane MG-220 self-priming base coat before
     applying topcoat.
     For concrete - immersion service, concrete must be abrasive blasted prior to sealing
     concrete with GemThane MG-201 penetrating epoxy
4)   On steel and ductile iron, thoroughly sand or grind surface. For immersion service, grit
     blasting to a 3 mil profile (75 microns) is recommended. Note: on steel, GemThane
     Aluminized Primer or UltraPrime would be a better choice.
5)   On other surfaces, sand thoroughly and test adhesion in a small area before proceeding.

1)   CHECK THE TEMPERATURE AND HUMIDITY:-- Do not apply if temperature is below 10°C
     (50°F) or if the dew point is within 3°C (5°F) of the ambient temperature (see Surface
     Preparation above). Otherwise curing, adhesion and performance will be affected. All
     application and surface preparation should be consistent with good painting practices.
2)   STIR INDIVIDUAL COMPONENTS:-- This is a two component system with a 1 part ‘A’ to 1
     part ‘B’ mix ratio by volume. Stir individual components thoroughly to assure homogeneity
     with a power mixer at slow speed. Caution: Do not introduce excessive air into the materials.
     Both ingredients (Part ‘A’ Resin and Part ‘B’ Hardener) should be between 21°C (70°F) and
     32°C (90°F) prior to mixing. If product has crystallized during storage, gradual heating,
     followed by stirring, will restore original consistency.
3)   MIX DESIRED AMOUNT OF ‘A’ AND ‘B’ TOGETHER:-- Into a clean container, scoop out
     equal parts of part “A” Resin and part “B” Hardener; using two small paper cups is ideal for this
     purpose. Immediately stir at slow speed with power drill mixer until thoroughly combined. To
     ensure complete mixing, scrape sides and bottom of containers. Incomplete mixing will result
     in soft spots or color variation.
4)   ADD REDUCER, IF DESIRED:-- The product may be thinned using Madison VR-4 Reducer
     ONLY. Do not use any other thinners or reducers with MG-201, whether from Madison or a
     third party, as they will be incompatible with MG-201 and will ruin the product. In most cases,
     5 to 10% of VR-4 reducer will be enough for ease of handling and maximum surface
     penetration. As an exception to this, when MG-201 is used as a penetrating sealer on wood it
     can be reduced by up to 50% in order to maximize penetration prior to applying a Madison
     intermediate coat or topcoat. See section below regarding decks and docks.
5)   RE-STIR OCCASIONALLY:-- Re-stir product every 10 minutes while using. Pot life will vary,
     depending on temperature, quantity mixed and amount of VR-4 reducer added; see chart
6)   BRUSH, ROLL OR SPRAY:-- Product may be applied using a brush, 3/8” or 1/4” nap paint
     roller, squeegee, or airless spray. When using airless spray we recommend using a 45:1 ratio
     pump, 0.021” - 0.027” orifice tip and a 3/8” material hose unless more than 50 ft. is required, in
     that case use a 1/2” material hose. If product has been thinned with VR-4 Reducer, pressure,
     hose size and tip size should be reduced accordingly. The desired application thickness may
     vary, depending on expected service conditions (i.e., chemical exposure, temperature, traffic
                                            Page 2 of 4
       load and other mechanical abuse, immersion service vs. splash-spill) and whether the product
       is being topcoated.
7)     SECOND COAT:-- A second coat may be applied over the first, so long as it is applied within
       the recoat window. Recoat window is dependent upon environmental conditions. Please refer
       below for GemThane MG-201 pot life and recoat window guidelines BELOW. Otherwise, it
       may be necessary to roughen the surface to ensure good intercoat adhesion.
8)     USING MG-201 AS A TOUCH-UP:-- When used as a touch-up, add 10 minutes for induction
       to increase build.
9)     CURING:-- Allow coating to cure completely before putting into service.

In the coating of wood, sealing with MG-201 is always a desirable practice but it is mandatory with
horizontal surfaces such as decks and docks. Ideal mixture for this type of application is 1 part ‘A’, 1
part ‘B’ and 1 part VR-4 Viscosity Reducer. Application by brush or roller rather than spray will give
the best penetration.

The topcoat should be GemThane Cottage Coat, in two separate applications applied at the rate of
about 250 square feet per gallon per coat (6 square meters per litre per coat). A six-litre kit will be
sufficient to provide two coats over an area of about 175 to 200 square feet (or about 15 to 18 square
meters. In other respects, follow the general Application Procedures set out above.


Pot life is the useful working time of the coating before it cures to a point where it can no longer be
properly sprayed, rolled or brushed. The values given in the following chart are approximate and
depend on several factors including coating thickness, amount of thinner used, ambient and surface
temperature. Actual time may vary.
      TEMP.             POT LIFE         CURE TIME            MINIMUM               MAXIMUM
        (°F)           (HRS: MIN.)         (HRS)            RECOAT TIME           RECOAT TIME
                                                                (HRS)                  (DAYS)
   70° (200C)             1:00                6                    6                      2

The pot life will be longer at cooler temperatures and shorter in warmer conditions.

Use Madison’s VR-4 Reducer only.

                                               Page 3 of 4

A)     A 2-4 mil build is usually obtainable with one coat.
B)     This product may not cure properly in temperatures below 10°C (50°F).
C)     When applying GemThane MG-201 in cooler temperatures 10°C-15°C (50-60°F) and high
       humidity, it is necessary to watch for the formation of an amine blush. This blush may appear
       as a milky white residue on the surface of the cured coating, but will not affect the integrity of
       the film. However, blush must be removed by solvent wipe or a light sanding if dry to touch
       (cured) before the application of another coat or intercoat adhesion problem will occur.
D)     All epoxies will show early chalking and yellowing on exterior exposure.

The information contained herein is believed to be accurate as of the date of publication. Madison
reserves the right to change product specifications without notice.

GemThane MG-201 is intended for industrial and professional use only. Product is non-flammable
and solvent-free but ample ventilation will dissipate any odours that occur during application. For
worker comfort, wear a NIOSH approved respirator suitable for organic vapor (i.e. a charcoal
activated cartridge mask. Wear rubber gloves, safety goggles and protective clothing as product will
be difficult to remove once it starts to polymerize (cure). If swallowed, DO NOT induce vomiting as
this will cause additional throat irritation; contact physician. If splashed on skin, remove immediately
with Madison VR-4 Viscosity Reducer and then wash with soap and water. If splashed in eyes, wash
liberally with clean water and contact physician; temporary irritation of eyes may last several days.
See MSDS for more information. The finished product is completely inert.

          The following are Trademarks and/or Registered Trademarks of Madison Chemical Industries Inc.:
        Madison Chemical, GemThane, MG-201, MG-220, GemBond, VR Reducers, PrepCrete and UltraPrime.

                                                                                                     Version 3, June 2009
                                                    F:\data\lit\library\GemThaneCoating\50apply\mg-201 aib ver 03 2009 06 10

                         GEMTHANE®, a division of MADISON CHEMICAL INDUSTRIES INC.
                              490 McGeachie Drive, Milton, Ontario, Canada, L9T 3Y5
                 Tel: (905) 878 - 8863    Fax: (905) 878 - 1449     E-mail:
                                               Page 4 of 4

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