This specification covers a topcoat for exterior metal (especially in marine environments), where water resistance and quick dry are required. It is designed for application on metal surfaces which have been treated with pretreatment, wash primer (DOD-P-15328), and coated with vinyl-red lead (MIL-P-15929) or vinyl-zinc chromate (MIL-P-15930) primer. It may also be applied over previously painted surfaces. The enamel shall be applied by spray or brush. Thinning with up to 5% n-butanol can Improve flow, leveling and adhesion properties. A 1:1 mixture of methyl isobutyl ketone and xylene shall be used for thinning at no more than 20% by volume for viscosity adjustment for spraying.