MIL-DTL-81706B
3.4 Toxicity. The material and processing baths or solutions shall have no adverse effect
on the health of personnel (see 6.5.2), when used for the intended purpose in accordance with
local process specifications (see 6.1).
3.5 Performance characteristics.
3.5.1 Corrosion resistance. After testing in accordance with 4.5.1 for applicable salt spray
exposure periods specified in table I, the specimens shall show no evidence of corrosion when
compared to unexposed control panels using the naked eye. Areas within 0.25 inch (6.35
millimeters [mm]) from the edges of the panel, the identification markings, and the panel holding
points during processing or salt spray exposure shall not be evaluated. Differences in color
between the test panels and the control panels shall not be cause for rejection.
TABLE I. Schedule for corrosion resistance properties of unpainted chemical films.
Corrosion Resistance
Aluminum Alloy To Be
Salt Spray
Class
Inspection
Conversion Coated
Exposure (Hours)
1A
2024-T3, 7075-T6
1/ 336
Qualification
3
6061-T6
168
1A
2024-T3
168
Conformance
3
6061-T6
168
1/ Exposure time for class 1A, form VI, method D materials shall be 168 hours.
3.5.2 Paint adhesion (wet tape). After application of the epoxy polyamide primer in
accordance with 4.4.4, no intercoat separation shall occur between the paint system, the
conversion coating, or the base metal, when tested in accordance with 4.5.2.
3.5.3 Paint adhesion (wet tape) after repair (applies to nonimmersion methods). After panel
repair and immersion in test fluid as specified in 4.5.3, the scribed panels shall exhibit no peel-
away and be rated at not less than 4A in accordance with ASTM-D3359. There shall be no
blistering of the unscribed coated area.
3.6 Coating weight (class 1A only). When tested in accordance with 4.5.4, type I coating
weight shall be not less than 40 milligrams per square foot (430 milligrams per square meter) of
surface area. Class 1A, type I, form VI, method D coating weight shall be not less than 10
milligrams per square foot of surface area (107.5 milligrams per square meter). Class 1A, type II
coating weight shall be not less than 10 milligrams per square foot of surface area (107.5
milligrams per square meter).
3.7 Contact electrical resistance properties (class 3 only). When tested in accordance with
4.5.5, the contact electrical resistance of aluminum alloy panels treated with class 3 materials
under an applied electrode pressure of 200 pounds per square inch (psi) shall be not greater than
5,000 microhms psi as applied and 10,000 microhms psi after salt spray exposure specified in
4.5.1. Individual readings not greater than 20 percent in excess of the specified maximums shall
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