Now prime and paint right over cured POR-15 with POR15 High Build Primer (was Tie-Coat Primer). This special \"interlocking\"  primer for painting over the top of POR 15 without any need to rough up or de-gloss. This primer is a tough yet sandable single component polyurethane primer, with special adhestion characteristics that make it perfect for most painted surfaces. It is highly resistant to penetrating topcoats, like lacquers, enamels, two-components finishes.  It sands very smoothly too. 946ml (US Quart) NOT suitable for use with cellulose paints. Surface Preparation: Surface to be coated should be free of grease, oil, and foreign substances. POR15 Cleaner Degreaser is ideal for this. The best method for over-coating POR-15 Rust Preventive Paint with POR15 High Build Primer is to first clean the surface with Cleaner Degreaser and then apply a coat of POR-15 Self-Etching Primer , following directions on the can. Then, over-coating with Tie-Coat can be done at any stage. Or lightly sand the  POR15 Rust Preventive Paint with 320 grit sand paper and topcoat with POR15 High Build Primer. *Other Painted Surfaces Clean with  POR 15 Cleaner Degreaser and paint with  POR-15 Self-Etching Primer following directions on the can; then over-coat with POR 15 High Build Primer. OR clean with  POR15 Cleaner Degreaser and sand with 240 grit and then overcoat with POR15 High Build Primer. Thinning: POR15 High Build Primer may be thinned up to 10% with POR15 Solvent (10 parts Primer to 1 part Solvent). Thinning may not be required if primer is to be brushed on. Application : Stir POR15 High Build Primer thoroughly before using. Do not shake as this will create air bubbles. Apply by brush or spray. Apply in thin coats. If applied too heavily, drying time will be lengthened considerably.  If a second coat is desired, wait a minimum of 12 hours before applying. You may sand between coats of primer, but adhesion will be better if you do not. Sand after final coat of primer has fully dried (24 hours). Top-coating Allow a minimum of 24 hours before applying any topcoat over the POR15 High Build Primer. Failure to allow enough time before applying topcoats may result in spidering or crinkling of finish. NOTE: In temperatures below 64 deg.F (18deg.C) cure times can lengthen considerably. POR15 High Build Primer is solvent-cured not moisture-cured, so allow extra days for curing in a low temperature environment. High Build Primer will not cure in temperatures below 52 deg. F(12 deg. C).