Raw, unfinished wood is porous and needs preparation prior to painting. While these steps can seem time consuming, they will save a lot of work in the long run. Sealing and priming the wood surface helps prevent sap from bleeding through the paint. Even though the wood has probably been kiln dried, there still might be some sap residue left within it.
Wood Preparation and Sealers
The wood surface should be smooth and free of dirt prior to sealing or painting. This way the paint will adhere properly. Run a hand over the surface to see how smooth the wood is. If there are rough surfaces, sand them with a super-fine grit sandpaper. Wipe away any sanding dust residue using a tack cloth or a clean, soft cloth. Apply a wood sealer using a clean paintbrush by moving the sealer in the direction of the wood grain. After the sealer is dry, lightly sand it with the super-fine sandpaper and clean it with the towel. Sealers are an important step in wood preparation. Sealers can be found in hardware or paint stores.
Priming the Wood
Any paint, sealer or primer should be used in a well-ventilated area. Priming helps stop the sap from discoloring the surface. There are many primers on the market; Kilz is a good product, though the odor is strong. Mix the primer well and apply it to the surface using a paintbrush and working with the grain of the wood. By following the wood grain, the final coat of paint will be pleasing to the eye. When using a water-based paint, also use a water-based primer and sealer.
Painting the Wood
Once the sealer and primer are dry and lightly sanded, paint can be applied to the wood. Follow the wood grain as before and apply a smooth coat of color onto the surface. Catch any drips to avoid marring the final effect. Lightly sand the first coat of paint if there are any rough spots. Wipe the surface clean and apply a second coat of paint.