MIL-DTL-53072E
coating application.
3.4.5.5 Application. All surfaces to be painted shall be thoroughly cleaned as specified in 3.2
and properly pretreated as specified in 3.3. To ensure a chemically clean surface, perform the
test in 4.2.3.1.1. Failure to comply with 4.2.3.1.1 is sufficient cause to do additional cleaning.
After completion of the 30 minute induction period, the primer shall be sprayed to achieve a DFT
between 0.6 and 0.9 mils (15 and 22.5 microns) for aluminum and between 0.8 and 1.2 mils (20
and 30 microns) for aluminum-steel assemblies. The primer needs only be dry to touch
conforming to ASTM D5895 before applying the topcoat. This is usually between 30 minutes
and 1 hour depending on conditions. The admixed primer shall be used within 4 hours to ensure
performance. The largest factor affecting cure is temperature. At 70 °F (21 ºC), the dry to touch
time is within one hour and the primer is dry to handle within 6 hours. The effect of decreasing
the temperature within a facility's painting area doubles the cure time for each 18 degree F (10
degree C) drop in temperature under 70 °F (21 ºC). Due to the fact that this is a water-reducible
system, a high relative humidity retards the cure time while a low relative humidity accelerates
the process.
3.4.5.6 Comments. The primer furnished under this specification shall be products which are
authorized by the qualifying activity for listing on the QPD (see 6.4). Since the sprayed primer
contains water, care shall be taken to ensure the surface is dry to touch before application of
urethane topcoats. Premature topcoating leads to an undesirable reaction between the water
evaporating from the primer and the catalyst component of the urethane being applied.
3.4.6 A-A-59745 (Zinc-Rich Coatings).
3.4.6.1 Description. These VOC compliant, zinc-rich coatings are designed for direct
application to blasted ferrous surfaces in place of other pretreatments. These coatings are either
two component epoxies or single component moisture cured polyurethanes. These coatings shall
contain a minimum of 90% by weight of zinc dust pigment in their dried films and conform to
Commercial Item Description (CID) A-A-59745, Zinc-Rich Coatings. The zinc-rich coatings
shall be subsequently overcoated only with MIL-DTL-53022 or MIL-DTL-53030 prior to the
application of the CARC topcoat at a minimum DFT of 1 mil (25 microns). These zinc-rich
coatings shall meet a VOC content no greater than 420 g/l (3.5 lbs/gal).
3.4.6.2 Use. These primers coatings are designed for enhanced corrosion resistance providing
cathodic protection and self healing properties. These products shall be used with CARC.
Epoxy primer MIL-DTL-53022 or MIL-DTL-53030 shall be applied at a minimum of 1.0 dry
mils (25 microns) as a barrier coat between the zinc-rich primer and the CARC topcoat.
3.4.6.3 Preparation. The pigment portion of the coating shall be thoroughly mixed prior to use
or admixing. Follow instructions specified by the manufacturer. Constant agitation shall be used
during application to prevent settling of the zinc pigment. The moisture cured type is a single
component and does not require any admixing. The epoxy two component types shall be mixed
following the manufacturers' specifications.
3.4.6.4 Reduction. If necessary and allowed due to environmental regulations, the zinc-rich
coating shall be reduced according to the manufacturer's recommended procedure. The single
component, moisture cured zinc-rich coating does not require any induction time, but the 2
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