UFC_3-190-06_Protective_Coatings_and_Paints.pdf

MIL-HDBK-1110

Textured Coating System for Concrete or Masonry

Surface Preparation Primer Topcoat

Power wash one coat primer recommended one coat TT-C-555 by supplier of textured 20 - 30 mils dft coating dft varies with supplier

4.4.2.4 Epoxy Coatings. A two-coat epoxy system will seal and protect concrete/masonry surfaces well. An aliphatic urethane finish coat should be used rather than the second epoxy coat on exterior surfaces to improve the weatherability.

Exterior Epoxy/Urethane System for Concrete or Masonry

Surface Preparation Primer Topcoat

Power wash one coat MIL-P-24441 MIL-C-85285 Formula 15 Type II 3 mils dft 2 mils dft

Interior Epoxy System for Concrete or Masonry

Surface Preparation Primer Topcoat

Power wash one coat MIL-P-24441 one coat MIL-P-24441 Formula 150 of another color 3 mils dft 2 mils dft

4.4.3 Recommendations for Steel. Presently, a high-

performance coating system is recommended to prolong the service before it becomes necessary to remove and replace it. Costs in coating removal, especially where there are restrictions on abrasive blasting, are very high.

Abrasive blasting is always preferred to alternative methods of preparing steel surfaces for painting. It cleans the steel and provides a textured surface to promote good primer adhesion. A commercial blast (SSPC SP 6) is normally adequate for alkyd and epoxy primers for a moderate environment. A near-white blast (SSPC SP 10) is required for epoxies, including zinc-rich epoxies, exposed to a severe environment such as marine atmospheric or water or fuel immersion. Some manufacturers may specify a white metal blast (SSPC SP 5) for particular coatings for special applications. It is important that a contract specification does not conflict with the coating manufacturer's 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

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 Composition B 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.