gal]\) as supplied by the manufacturer.

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MIL-PRF-23377K

4.5.3 Lifting. The primer coatings shall be applied to test panels designated A (see table I)

in accordance with 4.4.1. Panels shall air dry for 5 hours and then be topcoated in accordance

with 4.4.2. Examine for conformance to 3.7.3 during and after the drying of the topcoat.

4.5.4 Adhesion. Primer only in accordance with 4.4.1 and primer with topcoat in

accordance with 4.4.1 and 4.4.2 shall be applied to test panels designated C (see table I). The

test panels shall be immersed in distilled water for 24 hours at room temperature (see 4.5).

Remove the test panels from the water and wipe dry with a soft cloth. Within 3 minutes after

removal from the water make two parallel scribes with a stylus through the coating to the

substrate. The scribes shall be � of an inch apart and 2 inches long. The panels shall then be

scribed to the substrate from opposing ends of the parallel scribes to form an "X". Immediately

apply a 1-inch wide strip of masking tape with the adhesive side down across the scribes. Press

the tape against the surface of the coating by passing a 4-1/2-pound rubber covered roller,

approximately 3-1/2 inches in diameter and 1-3/4 inches in width across the tape eight times.

Remove the tape with one quick motion and examine for coating damage. Examine the coating

for conformance to 3.7.4. The masking tape shall have an average adhesion of at least 60-

ounces/inch width (3M Company #250 or equivalent as approved by the qualifying activity).

The tape shelf life is typically one year from date of manufacture.

4.5.5 Flexibility. The primer coating shall be applied to test panels designated B (see

table I) in accordance with 4.4.1. The coating shall be tested at the room temperature and relative

humidity conditions as specified in 4.5 and in accordance with ASTM D6905, using a Gardco

GE Universal Impact Tester, Model #172 (or equivalent as approved by the qualifying activity)

(see 6.7). Place the coated panel, film side downward, on the rubber pad at the bottom of the

impacter guide. Drop the impacter on the panel through the impacter guide, ensuring that the

impression of the entire rim of the impacter is made in the panel. Reverse the impacter ends and

drop it through the guide on the panel adjacent to the first area of impact. Using 10 power

magnification, examine for conformance to 3.7.5; record the percent elongation corresponding to

the largest spherical impression at which no cracking occurs.

4.5.6 Infrared reflectance (type II primer coatings only). The type II primer coatings shall

be applied to test panels designated A (see table I) in accordance with 4.4.1. The total

reflectance (specular and diffuse) of the primer coatings relative to barium sulfate shall be

measured using a near infrared spectrophotometer over a range of 700 to 2,600 nm. Examine for

conformance to 3.7.6.

4.5.7 Water resistance. The primer coatings shall be applied to test panels designated A

(see table I) in accordance with 4.4.1 and topcoated in accordance with 4.4.2. The coated test

panels shall then be completely immersed in distilled water maintained at 49 3 C (120 5 F)

for four days. Two hours after removal from the water, the coatings shall be examined for

conformance to 3.8.1.