Technical data

inhibitive wash coat or metal conditioner with the properties
of the conventional anticorrosive primer. This coating is
furnished with a resin component and an acid component,
which are mixed just prior to use. The resin component
consists of an insoluble zinc chromate and magnesium-
silicate in a polyvinyl-butyral resin and alcohol vehicle. The
acid component is phosphoric acid, ethyl alcohol, butyl
alcohol, and water. Wash primers can be formulated that are
equally effective over iron, steel, aluminum, treated magne-
sium, copper, zinc and a wide variety of other metals. The
advantages of wash primers used by the Air Force are listed
below.
• Apply easily and dry rapidly.
• Useable over wide ranges of temperatures and hu-
midity.
• Can be applied to a variety of metals with good
results.
• Provide temporary protection until protective coating
is applied.
• Prevent or retard under-film corrosion.
• Exhibit high degree of adhesion to metals.
• Upgrade performance of subsequent protective coat-
ings.
6.12.9.2 Uses. The primary purpose for wash primer is
as a intercoat between the base metal and the subsequently
applied primer coat. Primers that may be applied over wash
primer are MIL-PRF-23377, MIL-PRF-85582, TT-P-2760,
and TT-P-1757. This primer will not provide lasting protec-
tion. It is an alternate for MIL-DTL-5541, Class 1A conver-
sion coating on aluminum alloys.
NOTE
Do not use wash primer over one year old
without first checking its quality.
6.12.9.3 Mixing. Thoroughly mix each of the two com-
ponents using a mechanical shaker or approved equivalent to
reincorporate any settled portion. Slowly add one part (by
volume) acid component in small portions to four parts resin
component with constant stirring. Never add the resin com-
ponent to the acid component.
MIL-C-8514 is flammable and moderately toxic
to eyes, skin, and respiratory tract. Eye and skin
protection required. Good general ventilation is
normally adequate.
NOTE
The acid component is not a thinner but a
necessary activator. Do not vary the ratio of acid
to resin. Too little acid content in the wash primer
will result in poor coating adhesion and an excess
of acid will cause serious brittleness.
6.12.9.4 The pigment portion of the resin component may
settle and develop a hard cake during prolonged storage.
When this condition is encountered, pour the top liquid into
a separate container and break the hard cake with a paddle.
Gradually add the poured-off liquid in small amounts with
continuous stirring until the cake is reincorporated.
6.12.9.5 Pot Life. Polymerization starts immediately
when the acid and resin component are mixed, restricting the
pot life of the wash primer. If the temperature is below 90° F,
mix only the amount of wash primer that will be used in a
4-hour period. Limit the quantity to a 2-hour supply if the
temperature exceeds 90° F.
6.12.9.6 Thinning for Spraying. To spray uniformly
thin films of wash primer and to lessen cobwebbing, the wash
primer may require thinning with ethyl alcohol conforming to
Specification A-A-59282 (NSN 6810-00-127-4532). The cor-
rect spraying viscosity is 19 to 24 seconds in a No. 4 Ford
Cup (24 to 31 seconds in a No. 2 Zahn Cup). Wash primer
material may be suitable for spraying without thinning and
can actually be sprayed without apparent difficulty. However,
sometimes this results in a rough appearance which transmits
through to the topcoat, necessitating light scuff sanding to
give satisfactory appearance. Also, it will be more difficult to
obtain the correct uniform dry film thickness without thin-
ning.
6.12.9.6.1 Normal Atmospheric Conditions. Under
normal weather conditions (35 to 70 percent relative humidity
and 50° F to 90° F), thin with ethyl alcohol or a mixture of 90
parts ethyl alcohol to 10 parts butyl alcohol. A volume of
diluent (thinner) equal to the volume of acid component is
generally sufficient to obtain a wash primer of adequate
spraying viscosity. Use the ethyl-butyl alcohol mixture dilu-
ent only at the high end of the humidity temperature range
within the normal atmospheric condition since butyl alcohol
increases drying time.
6.12.9.6.2 Low-Humidity Conditions. Under low-
humidity conditions (less than 35 percent relative humidity)
and moderate temperatures (70° F to 80° F) prevalent in
heated areas during winter months, the normal dilution
specified above will result in poor intercoat and system
adhesion of subsequently applied topcoats. This difficulty
TO 1-1-8
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