MIL-PRF-14105E
4.24 Accelerated weathering. Prepare a coated steel test panel in accordance with 4.7 and air dry
for one hundred sixty eight (168) hours. Expose the panel for three hundred (300) hours to
accelerated weathering in accordance with ASTM G155 method A, type BH, and examine the
paint film. Nonconformance to 3.6.9 shall constitute failure of this test.
4.25 Recoating. Prepare two coated steel test panels in accordance with 4.7. Air dry one test
panel for eighteen (18) hours, and bake the other test panel in a well-ventilated laboratory oven
at 400 ºF (204 ºC) for one (1) hour. Allow the baked panel to cool to room temperature. Recoat
each panel as above, redry each panel as specified for the initial coat, and examine the paint film.
Nonconformance to 3.6.10 shall constitute failure of this test.
4.26 Adhesion. Spray the paint as in 4.7.2 on a steel panel prepared as in 4.7.1. After being bake
cured according to 4.6.2, perform adhesion testing as specified in ASTM D3359, method B and
examine for compliance with 3.6.11.
4.27 High temperature resistance.
4.27.1 Heat exposure cycle. Six (6) coated steel test panels shall be used in this test. Use five (5)
panels for further testing (see 4.27.2, 4.27.3, and 4.27.4) and one (1) for use as a comparative
standard. Prepare six (6) coated steel test panels (see 4.7.1) and bake for one (1) hour in accordance
with 4.7.2 except the panel thickness shall be 0.1875 inches (4.7625 mm) gauge minimum. The
blasting shall be in a 1.0 to 1.5 mil (25.4 to 38.1 microns) profile range. Subject the panels to one
heat exposure cycle consisting of heating for eight (8) hours at 400 ºF (204 ºC), cooling for sixteen
(16) hours at room temperature; then heat for eight (8) hours at 650 ºF (343 °C), cooling for sixteen
(16) hours at room temperature; heat again for eight (8) hours at 800 ºF (427 °C), and cooling for
sixteen (16) hours at room temperature; finish by heating for eight (8) hours at 1,400 ºF (760 °C).
Remove two (2) panels at the end of the 800 ºF (427 °C) heating period for use in the salt spray test
(see 4.27.2). Examine all panels at the end of each temperature variation. Nonconformance to
3.6.12.1 shall constitute failure of this test.
4.27.2 Salt spray. Panels from the 800 ºF (427 °C) heating period of 4.27.1 shall be tested for salt
spray resistance. Protect the exposed unpainted areas of panels with separate applications of paint
or wax. Make an "X" scribe to the base metal with each of the four (4) legs of the scribe being at
least 2 inches long and at least 0.5 inch from any test panel edge. Subject two test panels to 100
hours of salt spray in accordance with ASTM B117 using 5 percent salt solution, and examine.
Nonconformance to 3.6.12.2 shall constitute failure of this test.
4.27.3 Quenching cycle. Subject one heat exposed test panel from the 1,400 ºF (760 °C) heating
period to five quenching cycles consisting of heating the panel to 650 ºF (343 ºC) and plunging it
immediately into fresh tap water at a temperature of 70 ± 10 ºF (21 ± 5 °C). Examine the paint film
after each quenching cycle. Nonconformance to 3.6.12.3 shall constitute failure of this test.
4.27.4 Accelerated weathering (high temperature). Expose two test panels that have been
subjected to the heat exposure cycle 1,400 oF (760 °C) heating period to 300 hours of accelerated
weathering in accordance with ASTM G155, method A, type BH, and examine the paint film.
Nonconformance to 3.6.12.4 shall constitute failure of this test.
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