PRIMER COATING (TT-P-636)

TM 43-0139 2-15. PRIMER COATING (TT-P-636) a. Characteristics. Primer coating TT-P-636 is a red or brown iron oxide, alkyd-resin base primer that thas good adhesion, durability and flexibility, and covers in one coat. It has good resistance to weathering, although its intended use is as an undercoat. b. Use. WARNING This primer must NOT be used on the inside of drinking water tanks or on amphibious vehicles. (1) As a priming coat on synthetics, wood, bare or phosphate-treated ferrous metal parts (of motor vehicles, guns, gun mounts, tanks, and metal shipping containers), and other Ordnance materiel. (2) As a sealing undercoat on the wooden parts of motor vehicles. CAUTION This primer should not be used on steel vehicles, vessels, or structures that are exposed to acid fumes. c. Application. (1) Brushing. Apply as issued or by thinning with not more than five percent by volume of thinner. Apply one coat of primer for a two-coat finish and two coats for a three-coat finish. (2) Spraying. For spraying, thin with 15 percent by volume of mineral spirits paint thinner, TT-T-291, or synthetic enamel thinner, TT-T-306. d. Drying Time. (1) Before touching, air-dry for 20 minutes to two hours. (2) For thorough drying, air-dry for 18 hours or bake for 45 minutes at 250°F (121.11°C). (3) Recoating is permissible after air-drying for 10 hours. e. Thinner. Thin primer as required with mineral spirits paint thinner, TT-T-291, or gum spirits turpentine, TT-T-801. NOTE Olive-drab, rust-inhibiting enamel, TT-E-485, may be used in lieu of enamel TT-P-636. 2-6