MIL-DTL-24441D(SH)
4.5.3 Dust-free and dry-hard times. Prepare duplicate test panels by drawing down material prepared as
specified in 4.5.1 to a 75-micrometer (μm) (3-mil) wet film thickness on a ground glass panel. Cure one panel in a
dust-free location at 4.4±1 °C (40±2 °F). Determine the dry-hard time on each panel in accordance with ASTM
D1640. Dust-free and dry-hard time shall be in accordance with the requirements of the appropriate specification
sheet.
4.5.4 Pot life. Mix 1 liter of paint (1 quart) as specified in 4.5.1.3 from materials conditioned to 23+1 °C (73+2
°F). Remove mixed paint from the water bath at the following intervals from initial mixing and determine
consistency: 1 hour before the specified pot life and every half-hour for the remaining hour. Test may be
terminated whenever the consistency exceeds 625 grams or at the end of the specified pot life, whichever comes
first. Pot life shall be in accordance with the requirements of the appropriate specification sheet.
4.5.5 Gloss. Prepare a test panel by spraying out a 100-μm (4-mil) (nominal) wet film thickness of material
prepared as specified in 4.5.1, except allow a maximum of 2 hours conditioning prior to spray out on plain opaque
white glass or other suitable substrate using a suitable spray apparatus. Dry the film in a dust-free area for 24 hours
at 23 °C (73 °F) (nominal) and determine gloss in accordance with ASTM D523. Gloss shall be in accordance with
the requirements of the appropriate specification sheet.
4.5.6 Sag test. Test the paint mixed, as specified in 4.5.1, in accordance with ASTM D4400. Determine the
greatest value at which sag does not occur. Sag shall be in accordance with the requirements of the appropriate
specification sheet.
4.5.7 Color. Determine color in accordance with one of the following, depending on whether wet film or dry
film is specified.
4.5.7.1 Camouflage coatings. Wetted film for camouflage coatings (camouflage coatings are identified as
formulas 153, 154, and 155). Prepare the test panel by spraying on smooth steel a 100-µm (4-mil) (nominal) wet
film thickness of material prepared as specified in 4.5.1. Dry the panel for 16 hours at ambient laboratory
conditions, then 15 minutes at 52 ±3 °C (125±5 °F). The color shall be measured using ASTM D2244. Color shall
be in accordance with the requirements of the appropriate specification sheet.
4.5.7.1.1 Reflectometer. The reflectometer shall have a geometry with an illumination angle of 45 degrees
from the perpendicular, and a viewing angle of 0 degrees from the perpendicular. The reflectometer shall measure
green reflectance in the range of 0.80±0.01 to 4.00±0.01 percent. Any instrument with the required precision and
accuracy is suitable for use (see 4.5.7.1.4).
4.5.7.1.2 Wetting solution. Distilled water containing approximately 0.1 percent of a clear wetting agent
(detergent) shall be used for wetting the specimens. Solution shall wet the paint film in a sheet without foam.
4.5.7.1.3 Procedure. Cover the specimen to be tested with a thin film of the wetting solution mixture (see
4.5.7.1.2) and immediately obtain a green reflectance reading. Check specimen after obtaining reading for intact
water film. If water film is not intact, repeat procedure until a satisfactory reading is obtained on a fully wetted test
area.
4.5.7.1.4 Alternative color measuring equipment. Manufacturers can qualify alternative color measuring
equipment to NAVSEA or the General Services Administration (GSA) by demonstrating that the particular
instrumentation to be used measures the green color parameter with the accuracy specified in 4.5.7.1.1. The
manufacturer shall demonstrate that the alternate instrumentation can provide green color parameters that result in
the colors defined in the appropriate specification sheet.
4.5.7.2 Color of dry film of non-camouflage paints. Prepare a panel for test by spraying or drawing down upon
smooth steel or other suitable substrate a 100-µm (4-mil) (nominal) wet film thickness of material prepared as
specified in 4.5.1. Dry for 16 hours at ambient laboratory conditions, then 15 minutes at 52±3 °C (125±5 °F).
Compare the test panel with the standard color chip in accordance with ASTM D1729. If doubt exists as to whether
the match is satisfactory, determine the color difference by instrument as specified in ASTM D2244. An acceptable
color match shall be as specified in the individual specification sheets.
4.5.8 Brushing properties. Prepare the paint as specified in 4.5.1. Without further reduction, apply the paint in
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