Technical data

may be minimized by thinning with one part by volume of
thinner to five parts by volume wash primer with a thinner
composed of two parts (by volume) of distilled or deminer-
alized water and one part (by volume) of a 90:10 mixture of
ethyl alcohol: butyl alcohol. The above thinner composition is
a starting point and should be modified where local condi-
tions warrant. Table 6-1 shows the amount of each component
generally necessary to furnish a satisfactory wash primer.
6.12.9.6.3 High Humidity Conditions. Blushing of the
reduced wash primer may occur under high humidity condi-
tions (approximately 70 percent relative humidity or more).
Subsequently, applied topcoatings will not adhere to blushed
films. Blushing may frequently be eliminated by adding to or
substituting for the higher evaporation rate ethyl alcohol, a
lower evaporation rate blush-retardant solvent, such as
ASTM D2627, diactone alcohol, or butyl alcohol. The
diactone alcohol evaporates slowest and offers maximum
blush resistance.
NOTE
Do not use lacquer thinner to reduce wash primer
since it will increase the drying time of the wash
primer and, in case of high humidity, may prevent
drying of the wash primer for a period of several
days.
6.12.9.7 Film Thickness. The proper dry film thickness
is 0.2 to 0.3 mil. (wet film 0.6 mil). The wet film thickness
may be measured with a Nordsen Wet Film Thickness Gauge
or similar gauge.
Table 6-1. Thinning Ratio (Volume) for Wash Primer MIL-C-8514
Component Quantity Quantity Quantity
Resin 4 gallons 1 gallon 4/5 gallon
Acid 1 gallon 1 quart 1/5 gallon
Distilled Water 85 ounces 21 ounces 17 ounces
Ethyl Alcohol 39 ounces 10 ounces 1 ounce
Butyl Alcohol 4 ounces 1 ounce 1 ounce
NOTE
Place a small test panel(s) adjacent to the item
being coated, and measure the film thickness on
the test panel to assure proper wash primer
thickness.
6.12.9.8 Application of Wash Primer. Wash primer
may be applied by spraying, brushing, roller coating, or
swabbing on a clean metal surface. Spray the wash primer as
a thin film so that a continuous film may be obtained. A single
pass with the spray gun held 10 to 12 inches from the surface
is adequate. Do not attempt to get a full hiding coat as this
results in excessively thick coating. Too thick a coating is
undesirable because of poor adhesion of subsequent coatings
due to entrapped alcohol in the wash primer. Immediately
remove thick coatings with alcohol and reapply the coating
properly. Do not attempt to obtain a thin film by holding the
spray gun more than 12 inches from the surface as this results
in a dry, powdery film deposit that seriously impairs the
adhesion of the subsequent finish system.
NOTE
• Applying wash primer over oil residues results
in the dried wash primer having a shiny
appearance. Strip, reclean, and re-coat such
areas.
• DOD-P-15328, Coating Pretreatment (For-
mula No. 117 for metals), covers a material
very similar to Specification MIL-C-8514 ma-
terial. The main difference is the fineness of
grind of the pigment. It may be used as an
alternate for MIL-C-8514.
6.12.9.8.1 Low-Humidity Application. Wash primer
applied under low humidity conditions (less than 35 percent)
has a generally good resistance to fingernail scratches, but
adhesion of subsequently applied primers or topcoats will be
poor. Check the temperatures and relative humidity fre-
quently, and stop work when low relative humidity conditions
are encountered. If the relative humidity in the paint area
TO 1-1-8
6-15