TM 55-1500-345-23
epoxy type. The epoxy primer to use with steel sub-
4-4. PROCEDURES
FOR
APPLICATION
OF
strates is MIL-P-52192 and for aluminum and magne-
MIL-C-46168 PAINT TO BARE METAL SUB-
sium substrates is MIL-P-23377, or MIL-P-85582.
STRATES. The total paint system for the polyurethane
coating as with all other paint systems, requires cleaning,
a pretreatment coating, an anticorrosive primer and the
d.
Topcoat. MIL-C-46168 coating is applied at 1.8
polyurethane topcoat. This applies to painting of bare
to 3.0 mils dry film thickness in two coats. The first should
metal substrates.
be applied in one to four hours of the application of the
primer. The second coat may be applied within a few
a.
Cleaning. The substrate should be thoroughly
minutes of the first coat or anytime thereafter. The total
cleaned of all oil, grease and other contaminants by ap-
thickness of the topcoat should not exceed 3.0 mils.
propriate methods cited elsewhere herein or as specified
There is no maximum time between application of the
in TT-C-490.
first and second coats, ideally within two hours. No sur-
b.
Pretreatments. TT-C-490 finishing documents
face preparation, except for cleaning, will be necessary
e.g., MIL-STD-193, MIL-STD-186, MIL-T-704, etc., pro-
as long as the surface has not become contaminated,
vide appropriate directions for surface preparation. For
e.g., with dirt or grease. MIL-C-46168 coating fully cures
steel substrates, the pretreatments to use are zinc phos-
in 7 days.
phate or wash primer conforming to DOD-P-15328. For
aluminum, substrates, the pretreatment is alodine,
e.
MIL-DTL-64159 CARC topcoat is a alternate to
MIL-C-5541.
CARC MIL-C-46168. MIL-DTL-64159 has been evaluat-
c.
Anticorrosive Primers. The anticorrosive prim-
ed and approved for use by the AMRDEC Materials
ers to be used with the MIL-C-46168 paint system are the
Branch, Structures and Materials Division.
SECTION II. FIXED WING AIRCRAFT
c.
Aircraft Gray paint will conform to Military
Specification MIL-C-46168. For exceptions to aircraft
coat system consisting of a chemical conversion coating
gray, see Chapter 5.
applied to bare metal, followed by an intermediate primer
coat, MIL-P-23377 or MIL-P-85582 and then finish-
4-7. PROCEDURE.
painted with a lusterless topcoat.
a.
Clean and prepare aircraft surfaces for paint-
ing in accordance with Chapter 2.
4-6. MATERIALS.
b.
Apply chemical conversion coating in accor-
dance with manufacturer's instructions.
a.
The chemical conversion coating will conform
c.
Apply primer in accordance with the applicable
to MIL-C-5541 for aluminum and MIL-M-3171 for magne-
specification.
sium.
d.
Apply finish coats in accordance with instruc-
tions relating to application of MIL-C-46168 polyure-
b.
Intermediate primer will conform to Military
thane coating.
Specification MIL-P-23377 or MIL-P-85582.
4-3
