Painting Over Knotted Pine

Sanding

• Before attempting to seal knotty pine, it’s important to sand away imperfections. Start with 120-grit sandpaper on a sanding block or palm sander, then go back over the wood with 180- and 220-grit sandpaper. Between each sanding, wipe away the sanding dust with a lint-free cloth soaked in denatured alcohol.

Filling Holes and Cracks

• To ensure a smooth finish and minimize bleeding, you must fill holes and cracks with a wood filler. Because fillers shrink as they dry, knots might require multiple layers of filler. Once the final layer is dry, and cracks and holes are no longer visible, the filled areas should be sanded to match the rest of the board. The wood must be wiped clean and allowed to dry before the first coat of primer is applied.

Sealing

• Although shellac-based primers might advertise their ability to stop bleeding with a single coat, knotty pine should always get at least two coats. It’s best to seal the entire surface, as some resin sources might not be immediately obvious. Also, spot-treating knots with a pigmented shellac primer might result in an uneven top coat. For optimal results, apply an even coat of primer to the wood according to the manufacturer’s instructions. Allow the primer to dry for the specified length of time, then apply a second coat for added protection.

Painting

• To prepare the wood for its top coat, apply a thin, even coat of latex or alkyd primer. Allow the primer to dry thoroughly. Paint the primed wood with long, smooth strokes, following the grain. As with shellac-based primer, it’s best to apply two coats. To achieve a smoother finish, sand the wood lightly before applying the second coat of paint.