A beautifully painted wood surface can be quickly ruined if it is not properly protected. Painted wood furniture is especially susceptible to nicks, scratches, and water rings. A clear polyurethane topcoat can seal your painted wood surfaces and protect them from damage if properly applied. Follow these steps to seal painted wood with a clear polyurethane coating.
Wait at least four to seven days after painting the wood before you apply a sealer.
Protect your floor with dust sheets, and protect your hands with rubber gloves.
Wipe the newly painted surface lightly with a damp cloth to remove dust. Allow the surface to dry completely.
Apply a thin coat of polyurethane with long overlapping strokes of the brush.
Allow the thin coat of polyurethane to dry according to the product instructions.
Lightly sand the polyurethane surface with fine-grit sandpaper (at least 220 grit) to remove any tiny bumps or imperfections.
Wipe the surface with a damp cloth to remove sanding residue and allow the surface to dry completely.
Repeat the application process (steps four through seven) until two to three coats of polyurethane are applied.
If you are sealing painted wood that will be outdoors, make sure you use a product designed to endure the outdoor environment. Polyurethane is available in several finishes. Choose a matt finish for no gloss, or choose a semigloss or gloss to add shine. Polyurethane is also available in spray cans. If you are sealing an uneven surface or painted wood with a lot of detail, spray polyurethane is a great choice. Remember to apply thin coats and sand in between applications.
Never apply polyurethane without proper ventilation.