Installing the Retrofit Gasket Kit

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                                                                       0 Gram
                                                                                                Number 4/3

    Installing The Retrofit Gasket Kit
    The counter-height, single door, standard             Both foam and felt gaskets were attached with a
    museum cabinet has been in use by the National        pressure-sensitive adhesive. When force is
    Park Service for decades and has proven to be         repeatedly applied to the gasket from a single
    an excellent storage container for small to           direction over time, as in the act of replacing the
    medium-sized museum objects. (See Conserve            lift-off door or closing the swing door, the
    0 Gram 4/l .) The cabinet provides a relatively       adhesive loses its holding ability and the gasket
    stable microenvironment of minimally fluctuating      is forced out of position. This is known as
    relative humidity and temperature levels. It also     gasket creep. At this point, the desirable
    reduces the potential for damage caused by dust,      microenvironment cannot be maintained.
    air pollutants, insects, rodents, and light.
                                                          Replacing the Gaskets
    For the cabinet to provide      these beneficial
    conditions, the gasket that     lines the door jamb   NPS Curatorial Services Division staff have
    must be in good condition       and form a positive   worked with cabinet manufacturers to develop a
    seal against air infiltration   and biological        gasket retrofit kit that remedies the problems
    infestation.                                          caused by deteriorating foam or dangerous felt
                                                          gaskets and gaskets that creep out of position.
    Problems with Early Gaskets                           The kit is available to parks from the Curatorial
                                                          Services Division. (Curatorial Services Division
    In most standard cabinets in use by NPS and           can also provide source assistance to non-NPS
    manufactured before 1980, the gaskets were            users.) One kit provides the materials needed to
    made of polyurethane foam. However, in some           re-gasket a standard museum cabinet. By com-
    of the earliest cabinets the gaskets were made        bining kits, as described below, wardrobe and
    of arsenic- or mercuric chloride-impregnated          doublewide cabinet gaskets also can be replaced.
    felt. The felt was intended to kill insects
    trying to eat through it to enter the cabinet.        The kit gasket is a long-lived, chemically inert,
    These felt gaskets pose a potential health            stable silicone polymer and poses no health
    hazard to staff and, therefore, should be             hazard. The problem of gasket creep was
    carefully removed following the procedures            eliminated by attaching metal retainers that form
    given below.                                          a channel to prevent the gasket from moving out
                                                          of position. The installation of the gasket will
    Experience has shown that the more frequently         probably be a one-time replacement.
    encountered polyurethane foam gaskets readily
    deteriorate, primarily because of oxidation or        The illustration on page 3 shows how the retrofit
    exposure to ultraviolet radiation. Polyurethane       gasket kit is installed. The procedure applies to
    foam gaskets deteriorate and lose resiliency and      cabinets with both swing and lift-off doors.
    structural integrity in approximately two to five     All the components identified in the illustration
    years, at which point the foam crumbles and           are provided as part of the kit. In addition to
    falls away, causing the cabinet to lose the ability   the kit, the following materials and equipment
    to maintain a stable microenvironment.                are needed:
National Park Service                                                                 Conserve 0 Gram 4/3

    mineral spirits (e.g., V.M.&P. Naphtha)            5 Wipe the surface with denatured alcohol for a
    available at paint and hardware stores                final cleaning. Touch up the surface as
    denatured alcohol                                     needed by applying a rust-inhibiting enamel
    rust-inhibiting enamel paint, varnish, or             paint, varnish, or lacquer to all areas of bare
    lacquer, available at paint and hardware stores       metal on both sides of the cabinet door
    single-edge razor blade or utility knife for          opening, including drilled holes.
    removing old gasket
    steel file, medium tooth                           6. Pop-rivet each retainer in place.    Continue
    power drill                                           until all four retainers are in position.
    pop riveter
                                                       7. Remove the backing paper that covers the
Procedures for Installing the New Gasket                  adhesive on each piece of gasketing and place
                                                          the gasket into the channel formed by the
Safety Precautions. When filing and drilling              metal retainers and the jamb of the door.
metal cabinets, wear latex gloves, a dust                 Install top, bottom, and side gaskets so that
respirator, and safety goggles.                           the gasket ends abut, forming a continuous
                                                          seal around the door jamb.
If pesticide-impregnated felt gaskets must be
removed (described on page l), wear latex              8 Door fit generally will be tight after the new
gloves and a respirator with an organic                   gaskets are installed. If the door fits too
vapor/high-efficiency particulate air (HEPA)              tightly to be closed, minor door adjustments
filtering cartridge. Clean up all felt and dusty          can be made as follows:
residue, seal it in a jar or can, and label clearly.
The felt must be disposed of as toxic waste, in              The latch side can be adjusted by filing the
accordance with the Park’s Hazardous Waste                   ends of the vertical latch bolts or by
Disposal Program. Contact the Park or the                    enlarging the holes in the door jamb where
Regional Hazardous Waste Coordinator for                     the bolts engage.
disposal guidance.
                                                             The hinge side can be adjusted by bending
1. Read instructions that are provided with the              the hinges slightly. They can be bent
   kit.                                                      outward by placing a screwdriver or
                                                             similar object in the fold of the hinge and
2. Remove objects and drawers from the cabinet               closing the door.
   and place them in a secure location.
                                                       By combining components from additional kits,
3. Remove the old gasket with a utility knife or       doublewide and wardrobe cabinets that fit the
   single-edge razor blade. Use mineral spirits,       NPS modular size system (see Conserve 0 Gram
   if necessary, to dissolve the adhesive. Check       4/l) can be re-gasketed. All the components
   this surface and file as needed to make it          from two kits are required for a wardrobe
   smooth and flat. If welds protrude above the        retrofit. A doublewide cabinet will require two
   flat metal surface at the corners, file them        kits minus the two side retainers.
   flush with the adjacent metal.
                                                       Donald R. Cumberland, Jr.
4. Place each retainer in the proper position (see     Museum Specialist
   illustration) making sure it lies straight and      Curatorial Services Division
                                                       National Park Service
   flat. Then, using the holes in the retainer as
                                                       Harpers Ferry, West Virginia   25425
   a guide, drill matching holes in the case
   through the surface just cleaned.                   Formerly issued us Conserve 0 Grum 4/8.   Revised 1993.

2                                                                        Installing the RetroJit Gasket Kit
                                                     N&iomd Park Service
Conserve 0 Gram 413

                    Retrofit Gasket Kit for NPS Standard
                              Museum Cabinet

                 Drilled _Holes

                                                ;_        Standard Museum

  0 14 Pop Rivets

  0 1 Top Retainer XAngle 6”
        l/4” X 3/4”  26 5/j

  0 1 Bottom Retainer Angle
            l/4” X 3/4” X 26 5/q 6”

   D    2 Side Retainer Angles
            114” X 3/4” X 32”

   E    4 Gaskets (1 Top, 1 Bottom, 2 Sides)

   0F   1 l/g’ Drill Bit

   G    1 Set of Instructions

   Installing the Retrofit Gasket Ka
National Park Service                                                                                             Conserve 0 Gram 4/3

The Conserve 0 Gram series is published as a reference on                 The series is distributed to all NPS units and is available to non-NPS
collections management and curatorial issues. Mention of a product,       institutions and interested individuals by subscription       through the
a manufacturer,   or a supplier by name in this publication does not      Superintendent    of Documents,    U.S. Government      Printing Office,
constitute an endorsement of that product or supplier by the National     Washington,    D.C. 20402, FAX (202) 512-2233.                For further
Park Service.   Sources named are not all inclusive.    It is suggested   information and guidance concerning any of the topics or procedures
that readers also seek alternative product and vendor information in      addressed in the series, contact the National Park Service, Curatorial
order to assess the full range of available supplies and equipment.       Services Division, Harpers Ferry, WV 25425, (304) 5356410.

4                                                                                                Installing the Retrofit Gasket Kit