MIL-HDBK-1110
Epoxy System for Interior Steel
Surface
Preparation
Primer/Mid Coat
Topcoat
SSPC SP 6 or 10
one coat each MIL-P-24441
one coat
Formulas 150 and 151
MIL-P-24441
3 mils dft per coat
of desired color
3 mils dft
4.4.3.3
Zinc-Rich Coatings. Good protection from corrosion and
abrasion can be provided by zinc-rich inorganic coatings. They
perform well untopcoated in a variety of environments except
acidic or alkaline. They may be topcoated with an acrylic latex
finish coat to provide a variety of color finishes. Epoxy (for
interior) or epoxy and aliphatic urethane (for exterior)
topcoats may also be used. Localized repair of inorganic zinc
systems is usually accomplished with a zinc-rich organic coating
to permit good bonding to any exposed steel, inorganic coating,
or organic topcoats.
Zinc-Rich System for Steel
Surface
Preparation
Primer
Topcoat
SSPC SP 5
1-MIL-P-24648
None, or one or
more coats of
(inorganic), 3 mil dft
acrylic or latex,
(Composition A (organic) epoxy, etc.
can be used when a more
"forgiving" system is needed,
refer to pars. 2.3.8 and 2.3.9)
4.4.4
Recommendations for Galvanized Steel. Galvanized steel
corrodes very slowly in moderate environments but may be painted
with organic coating systems to provide color or additional
corrosion protection, particularly in severe environments. It
should never be coated directly with an alkyd paint, because the
alkalinity on the surface of the galvanizing will hydrolyze the
oil in the binder, degrading the binder, and cause paint peeling.
New galvanizing should be solvent or steam cleaned
(SSPC SP 1, Solvent Cleaning) to remove any grease or oil before
coating. Older, untopcoated galvanizing should be power washed
to remove any dirt or loose zinc corrosion products. Any loose
coatings should also be removed by power washing or scraping and
sanding to produce a clean, sound surface. Rust should be
removed by waterblasting or careful abrasive blasting to limit
the removal of galvanizing.
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