MIL-DTL-3688D
a Fisher-Johns melting point apparatus. The temperature increase shall not exceed 35.6°F (2°C)
per minute. Record the temperature at which the sample is completely liquefied. Check for
compliance with 3.9.
4.4.8 Stability to centrifuging. A sample of the wax emulsion shall be centrifuged for 15
minutes at a temperature of 100° ± 2°F (38° ± 1°C) and a speed of 750 revolutions per minute.
Check for compliance with 3.10.
4.4.9 Drying time. Draw down a film of wax emulsion with a 3 ml drawdown knife on a clear
glass plate prepared as in ASTM D3891. The thickness of the dried emulsion shall be 1.5 ml ±
0.2 ml. Perform the "free from after-tack" procedure described in Method 4061.3 of FED-STD-
141 for compliance with 3.11.
4.4.10 Appearance of dried film. Glass plates with wax emulsion, prepared and dried as in
4.4.9, shall be viewed through the under side with bright daylight transmitted through it. The
film shall comply with the requirements of 3.12.
4.4.11 Dipping properties. Obtain two phosphate coated, low carbon steel (SAE 1010) panels, 4
x 12 inch x 0.026 inch thick (10 x 30 cm x 0.065 cm) conforming to QQ-S-698 (see 6.3). Record
weight of phosphate coated panel and begin dip application under conditions according to ASTM
D823 method B. One minute after immersion, withdraw panel instantly and keep it in a vertical
position for approximately 30 minutes. Air dry the panel to a constant weight. Subtract weight
of phosphate coated panel from weight of wax coated panel and record difference as weight of
wax coating. Compute a gm/ft2 of coating, based on a test area coverage of 2/3 ft2. Observe
dipping properties for compliance with 3.13.
4.4.12 Spraying properties. Obtain two phosphate coated, low carbon steel (SAE 1010) panels,
4 x 12 inch x 0.026 inch thick (10 x 30 cm x 0.065 cm) as in 4.4.11. Record weight of phosphate
coated panel and spray the unreduced wax emulsion on both sides of the panel to produce a
uniform coating surface. Dry the panel in a vertical position and compute weight per ft2 of
coatings as in 4.4.1l. Observe spraying properties for compliance with 3.14
4.4.13 Brushing properties. Obtain two phosphate coated, low carbon steel (SAE 1010) panels,
4 x 12 inch x 0.026 inch thick (10 x 30 cm x 0.065 cm) as in 4.4.11. Record weight of phosphate
coated panel, and brush the unreduced wax emulsion on both sides of the panel and examine as it
dries. Dry the panel in a vertical position and compute weight per ft2 of coating as in 4.4.11.
Observe brushing properties for compliance with 3.15.
4.4.14 Adhesion of tape to wax film.
4.4.14.1 Apparatus.
(a)
Eight phosphate coated, low carbon steel (SAE 1010) panels, 4 x 12 inch x
0.026 inch thick (10 x 30 cm x 0.065 cm) as in 4.4.11. Cut these panels to 1 ½
inch x 4 inch (3.8 x 11.4 cm).
(b)
Eight strips of tape, each 1 x 8 inch (2.5 x 20 cm), conforming to
ASTM D5486/D5486M.
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