MIL-DTL-82604A (OS)
4.5.8 Acid resistance. Place a panel, prepared as described in 4.5.7.1, on a flat horizontal
surface. Place drops of the following solutions at different places on the coating:
Saturated picric acid
Sulfuric acid, sp. g r. 1.30
Nitric acid, sp, gr. 1.22
Hydrochloric acid, sp. gr. 1.09
Allow the acids to remain in contact with the coating for 6 hours while the temperature is
maintained at approximately 21 ºC. Cover the drops with small watch glasses in order to
prevent evaporation. Remove the acids by washing with cold water and dry the film at room
temperature for 1 hour. Examine the areas previously in contact with the acids and note if the
compound is resistant to each of these acids as indicated by absence of disintegration,
browning, or dulling of the coating. Do not consider a slight bloom around the area of a spot
exposed to acid as an indication of failure to resist the acid. Remove the coating with benzene
and examine the metal. Note if the coating has resisted the action of each acid as indicated by
the absence of any corrosion of the metal.
4.5.9 Water resistance. Suspend a panel, prepared as described in 4.5.7.1, in a beaker of
cold distilled water for 18 hours so that the uncoated end of the panel is uppermost and one-half
of the coated portion is submerged. Examine the panel for blistering, whitening, softening, or
other visible defects.
4.5.10 Flexibility. Clean a strip of No. 30-gage hot-rolled steel sheet, 2 by 8 inches, by
washing with benzol and thoroughly drying. Coat a preheated strip on one side to a thickness of
1/16 inch by flowing on the molten compound and then cooled at room temperature for a period
of 6 hours. With the coating on the outside, bend the test panel rapidly 180 degrees over a
mandrel 1 inch in diameter. Ensure no macroscopic cracking of any kind is visible after the
bending test.
4.5.11 Reactivity. (First article test by designated activity only unless otherwise specified.)
Determine the reactivity of the asphaltic compound in contact with H-6 and tritonal explosives in
accordance with the vacuum stability test procedures of 4.5.11.1 through 4.5.11.4.
4.5.11.1 Preparation of samples. Heat the compound until pourable, then deposit on
glass plates a sufficient amount of the compound to provide 2.5 (N+2) g of dried film (where N
equals the number of explosives involved). Air-dry the films under ambient conditions for 48
hours. After drying, remove and cut into approximately ¼-inch squares. Conduct this operation
in a room that is free from acid, alkaline, or other contaminating fumes. Reduce the explosive
materials to 12 mesh or finer by grinding or rasping. Keep both the compound film and the
ground explosives dry by storing in a desiccator over a desiccating agent until ready for testing.
4.5.11.2 Calibration of apparatus. Calibrate the necessary number of vacuum stability
test assemblies, as directed in procedure 4.1 of method 403.1.3 in MIL-STD-286.
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