Typical Uses: TT-P-645A is an air dry alkyd, zinc chromate type primer for applications to steel and aluminum. It is intended for use as a corrosion inhibiting primer on metal surfaces. The colors of the Navy Formulas are: Formula 84 yellow; Formula 84D green; and Formula 84B red iron oxide (brown). Application Cleaning Parts to be coated must be cleaned using a recognized cleaning method. The surface must be free of dust, grease, film and old paint. Mixing Brush or roll at package viscosity. When spraying, reduce eight parts of primer with one part thinner. Use PT-1022X66 Solvent Blend for spraying. More may be added if necessary. A high grade mineral spirits conforming to TT-T-291 may also be used. Method of Application Brush, roll or spray. Curing Air Cure: Set to touch: 1 hour maximum. Dry hard: 6 hours maximum Full cure: 72 hours Force Dried: May be force dried at 150 deg. F. for 1 hour Application of topcoat: Topcoat may be applied 1 hour after primer is sprayed