MIL-PRF-24712B, PERFORMANCE SPECIFICATION: COATINGS, POWDER, THERMOSETTING (11-FEB-2014)

MIL-PRF-24712B, PERFORMANCE SPECIFICATION: COATINGS, POWDER, THERMOSETTING (11-FEB-2014)., This specification covers thermosetting powder coatings for shipboard metallic equipment, furniture, electrical enclosures, and other miscellaneous metal parts and outfitting hardware in non-immersion service in both interior and exterior environments. Although the qualification tests are performed over steel surfaces, these coatings are intended for use over bare steel substrates and may be used over other alloys or materials as appropriate. Powder coatings in accordance with this specification may be able to be applied by electrostatic spraying, flocking, or fluidized bed methods, depending on the specific product vendor recommendations. Not all classes under this specification are intended for use for each type. Table V shows the intended qualifications allowed for each type and class, with further intended uses described below: a. Type I and II epoxy powder coatings should not be used as topcoats in exterior service due to their poor weathering properties, but when used as a primer in a two-coat system, they can be top-coated with a Type III or IV coating. b. In a two-coat system, a Type I or II epoxy primer optimizes corrosion control performance, while a Type III or IV polyester or hybrid coating optimizes resistance to color and gloss change due to topside weathering. c. All types of coatings are intended to provide satisfactory performance for most shipboard interior dry service applications. However, there is limited color availability for Type II, zinc-rich epoxy powders.