gal\)\). This coating is lead and chromate free. The coating is supplied as a kit.

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MIL-PRF-22750G

tube shall also act as the test "blank". Immerse a lead test strip into the supernatant from each tube.

Shake off the excess liquid and after approximately one minute compare the color change in the

reaction zone of the strips to the color scale (concentration levels) provided by the manufacturer. If

any color change is apparent from the "blank" strip rerun the test using fresh, lead-free reagents.

For the "Sample" strip, the appearance of a bright red color is indicative of lead at a concentration

level above the specification limit, while no color change or a faint pink color change is indicative

of lead concentrations below the specification limit. Confirmation of the exact lead concentration

in the coating's solids shall be determined using any authoritative quantitative method, such as

ASTM D3335.

4.7.1.2 Hexavalent chromium. Determine the presence or absence of hexavalent chromium by

either of the following chemical reagent screening techniques.

(a) Weigh approximately 250 mg of pigment into a small glass test tube. Add 5 ml of 25

percent aqueous KOH and shake vigorously for 1 - 2 minutes. Decant a one ml aliquot into a

plastic micro-centrifuge tube and centrifuge for five (5) minutes at 17000 rpm, balancing the

centrifuge with a tube containing one ml of the KOH solution. The resulting supernatant liquid

shall be nearly colorless. Use the tube containing the KOH solution as a reference. A distinct

yellow color indicates the presence of hexavalent chromium and therefore shall constitute failure

of the test requirement.

(b) Weigh approximately 50 mg of pigment into a small glass test tube. Add 5ml of 10 percent

aqueous H2SO4 and shake vigorously for 1 - 2 minutes. Decant a one ml aliquot into a plastic micro-

centrifuge tube and centrifuge for five (5) minutes at 17,000 rpm, balancing the centrifuge with a

second tube containing one ml of the H2SO4 solution. The solution in the second tube shall act as the

test "blank". Immerse a chromate ion (CrO42-) test strip into the supernatant from each tube. Shake

off the excess liquid and after approximately one minute compare the color change in the reaction

zone of the strips to the color scale (concentration levels) provided by the manufacturer. The

appearance of a purple/violet color from the "sample" strip is indicative of hexavalent chrome and

therefore shall constitute failure of the test requirement. If a color change is apparent from the

"blank" strip rerun the test using fresh, chromium-free reagents. The appearance of a pronounced

color change is indicative of hexavalent chrome and therefore shall constitute failure of the test

requirement.

4.7.1.3 Antimony, arsenic, beryllium, cadmium, chromium, cobalt, cyanide, manganese, mercury,

nickel and selenium. Manufacturers need to review applicable environmental and safety regulations

and comply with material shipment requirements (see 6.2). The MSDS needs to include a notarized

statement that verifies that the composition of the material (coating formulation) is free of the

antimony, arsenic, beryllium, cadmium, chromium, cobalt, cyanide, manganese, mercury, nickel,

selenium and their compounds.

4.7.2 Volatile content. The volatile content of the admixture (see 3.3.2) determined by EPA

method 311 and the VOC analysis (see 3.3.2.1 and 3.3.2.2) determined in accordance with ASTM