APPENDIX I
COCOONING PROCEDURE
with the wiring diagram furnished with the instrument.
1. General. The basic requirements for the cocconing
of railroad equipment involves the fabrication of pans,
installation of dynamic dehumidification systems,
5.
Dehumidification Machine.
A package
shrouding of equipment, and the application of three
coats of sprayable plastic coating, and one coat of
10,000 cubic foot capacity, 110-volt, alternating current,
aluminum coating.
will be attached to the dry air and moist air ducts and
humidistat. The machine will be located outside the
package. To prevent damage to the motor, full current
2. Fabrication of Pans. Pans will be fabricated of No.
(110 volts) must be delivered to the machine.
20 gage galvanized sheet metal with 3/8-inch double lock
seams. Seams will not be soldered. The length of the
pan will be approximately 3 feet greater than the overall
6. Preparation of the Package. Cushioning material
length of the item. The height will be approximately 6
will be applied to all sharp edges and projections of the
inches. The corners of the pan will be blunted or
equipment. The equipment will be covered with a snug-
rounded to prevent chafing of the plastic barrier. The
fitting shroud of osnaburg cloth conforming to FED CCC-
bottom (outside) of the pan will be coated with
C-429, or if that material is not available, with burlap
bituminous coating conforming to MIL-C-3254, type II
conforming to FED CCC-C-647. The shroud will be
before the pan is placed on the rails. Do not apply
fastened to the sides of the pan with adhesive
compound to the vertical lip of the pan. The seams on
conforming to FED MMM-A-189. The fabric will be the
the inside of the pan will also be coated with the
base for the sprayable plastic coating.
bituminous material. The pan will then be placed on the
rails with one end slotted to allow the equipment wheels
7. Spraying Plastic Coating. The fabric will be sprayed
to enter. After positioning the equipment, patches will be
with three coats of sprayable plastic conforming to type I,
secured over the slots by riveting or use of zinc coated
class 2 of MIL-C-3254. Each coat will be dyed a different
sheet metal screws. Minor crevices will be filled from the
color as visual aid to obtain adequate coverage. The
inside, using bituminous coating. Optionally, for ease of
first coat is dyed yellow, the second is red, and the third
handling, the pan may be fabricated in sections and after
blue. The plastic will be dyed by adding 2 ounces of dye
delivery to place of use, the sections joined by a double
to each 5 gallons of plastic solution, using butter yellow
row of rivets. The overlap for riveting should be
approximately 4 inches, to permit the rows of rivets to be
6820-286-5484), and blue aniline dye (FSN 6820-255-
2-3/4 inches apart.
8201) respectively for the first, second, and third coats.
The recommended pressures are 20 to 30 pounds on
3. Installation of Ductwork. After placement of
the fluid tank and 70 pounds minimum atomizing
equipment on the pan, the dry air and moist air return
pressure at the gun. The fluid pressure will be increased
ducts will be placed in position. The ducts will be 4-inch
when more than one gun is used. The gun should be
diameter galvanized sheet metal or flexible tubing. A
held 8 inches from, and perpendicular to, the surface
sheet metal support riveted to one end of the pan is
being coated. The surface of the coating should appear
useful for securing the ducts at the points of intersection
wet and glossy. The thickness of each coat will be
with the barrier. The dry air and moist air return lines
approximately .015 inch. When the density of color of
should terminate near opposite ends of the package.
the sprayed coat matches that of the material in the
The dry air line will be carried upward 6 to 8 feet above
supply tank, it would indicate that the thickness is
the pan. The moist air will be drawn from the bottom of
correct.
the package, preferably inside the engine compartment
near the floor.
8. Bituminous Coating. The coating material will
conform to type II of MIL-C-3254. The type I plastic
4. Humidistat. A humidistat set to operate at 40
coating must be allowed to dry thoroughly (48 to 72 hr)
percent relative humidity will be installed near the center
before the bituminous coating is applied. The coating
of the package. Wiring will be attached in accordance
should be approximately
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