MIL-HDBK-1110
written directions. A white metal blast (SSPC SP 5) is
recommended for zinc-rich inorganic primers. If abrasive
blasting cannot be done, then power tool cleaning to bare metal
(SSPC SP 11) is recommended. It provides a surface cleanliness
and texture comparable to those of a commercial blast (SSPC
SP 6). Hand tool cleaning (SSPC SP 2) or power tool cleaning,
however, may be adequate in making localized repairs.
4.4.3.1
Alkyd Systems. In the past, most military steel
structures with atmospheric exposures were coated with an alkyd
or other oil-based system. Three-coat alkyd systems provided
adequate protection in moderate atmospheric service. On new
painting, they are being replaced in significant part by epoxy
systems that provide longer protection. Alkyd systems, however,
will still be used in large volume for repairing old deteriorated
alkyd systems.
Alkyd Coating System for Steel
Surface
Preparation
Primer
Topcoat
SSPC SP 6
one coat TT-P-645 or
two coats MIL-E-24635
SSPC PAINT 25
or TT-E-489
2 mils dft
2 mils dft
4.4.3.2
Epoxy Coating Systems. A three-coat epoxy system
provides good interior service in harsh as well as moderate
environments. An aliphatic urethane finish system is used in
place of the third epoxy coat in exterior service to provide
greater resistance to deterioration by ultraviolet light.
Several different epoxy mastic systems, some aluminum-filled,have
been used successfully on steel structures. However, there is no
specification for one at this time.
Epoxy System for Exterior 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-C-85285 Type II
3 mils dft per coat
2 mils dft
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