Section III. PRIMERS
Primers are applied to metal to provide an initial coating to which a second coating (i.e. a topcoat) will firmly adhere. The
pigment composition of primers for ferrous-base metals usually consists of iron oxide, titanium dioxide, lead chromate, red
lead, zinc chromate, zinc dust, zinc oxide and zinc phosphate, or a mixture of these. Zinc chromate is the principal
pigment in primers used on aluminum, magnesium, alloys, and on items that will be exposed to damp or wet operating
2-9. Primer Coating, Epoxy-Polyamide, Chemical and Solvent Resistant (MIL-P-23377, Type I)
Characteristics. This primer specification covers two types of two-component, epoxy-polyamide, chemical and
solvent resistant primers formulated for spray application and compatible with polyurethane topcoats. They are lead free
but contain chromate.
Use. They are intended for use of pretreated aluminum alloy surfaces as a corrosion inhibitive, chemical resistant,
strippable, epoxy primer that is compatible with urethane topcoats. It should only be used on nonferrous surfaces. It is a
primer for use with CARC paints.
Application. Thoroughly mix each of the components separately. Component B is slowly poured into Component
A with constant stirring until a one-to-one volume ratio is achieved. An induction of 30 minutes is necessary after mixing.
Epoxy primers have a pot life of 15 hours.
Drying Time. The primer will dry to touch in 30 minutes and dry hard within six hours.
Thinner. Thin with MIL-T-81772, Type II. When spraying, thin to a viscosity of about 16 seconds in a viscosimeter
2-10. Primer Coating, Epoxy (MIL-P-52192)
Characteristics. This is an air-drying or baking, chemical resistant, epoxy-resin, lead and chromate formulation,
compatible for use with polyurethane topcoats.
Use. It is intended for used on pretreatment ferrous surfaces. It may be baked at 3000F for 20 minutes, or at
lower temperatures for a longer period of time. It has good exterior durability and will withstand 1,1,1 trichlorethane
degreasing vapors. It is a primer for use with CARC paints.
Application. Thoroughly mix each of the components separately. Mix four parts of Component A to one part of
Component B by volume, and stir until well blended. An induction of 30 minutes is necessary after mixing. Epoxy primers
have a pot life of 15 hours.
Drying Time. The sprayed primer will be set to touch in 10 minutes and dry hard within one and one-half hours.
Thinner. Thin with MIL-T-81772, Type II. This primer may be thinned up to 20 percent by volume.
2-11. Primer, Epoxy Coating, Corrosion Inhibiting, Lead and Chromate Free (MIL-P-53022)
Characteristics. This is a two-part, flash drying corrosion inhibiting, lead and chromate free epoxy primer for use
on pretreated ferrous and non-ferrous metals which must meet air pollution requirements.
Use. It may be used to replace MIL-P-23377 and/or MIL-P-52192 where exposure to lead and chromate pigments
is not permitted. It is a primer for use with CARC paints.
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