Preparing wood for staining is easy, but it helps to keep a few important guidelines in mind.
First, it is important to thoroughly check the entire surface of the part to be stained for imperfections and defects. Small holes, such as nail holes, can be filled with wood filler that matches the natural color of the wood. Once you sand the filler smooth, you can even scratch lines to mimic the wood grain. Countersunk screws can be hidden with wooden plugs that are cut flush with the surface and sanded down.
It is very important to sand the entire piece. Sanding not only creates a nice smooth finish, but it also helps open up the pores of the wood so it absorbs the stain properly. Think of wood as an absorbent material. Anything that interferes with the absorbency of the wood should be avoided or remedied as it will cause uneven staining. For that reason, any oil, grease or glue must be removed by sanding. Even natural oil from fingerprints can cause unsightly stains when wood is stained. Be sure to check the joints for any excess glue that may have covered a small part of the surface to be stained.
To sand properly, you should always sand with the grain of the wood and not against the grain. Sanding against the grain causes scratches that will be very apparent when the stain is applied. Sandpaper is graded according to the number of grits per square inch, so the small numbers refer to coarse sandpaper and the larger numbers are for finer sandpaper. If there are no extremely rough areas on the piece to be sanded, you can start with 120 grit paper.
Sand the entire piece and switch to 220 grit sandpaper. As you continue sanding, you’ll need to move on to finer and finer sandpaper. Sanding sponges are great for sanding surfaces that are not flat, like trim, as they are flexible and conform to the shape of the particular surface.
Once the part is thoroughly sanded, it is important not to touch it with bare hands, as this will leave new oil on the surface. Instead, you can handle it with clean gloves or rags. Dust left on the surface during the sanding process should be removed with a clean rag or tack cloth. Make sure the piece does not come into contact with water, as the water will raise the grain of the wood and cause the stain to stain differently.
For best results, you can apply a wood conditioner before staining. Wood conditioner helps the stain absorb evenly into the wood.
It’s always a good idea to test the stain on a small piece of identical wood first to make sure the color is to your liking. When you have tested the stain and are satisfied with the results, you can stain the piece. Simply brush it with the grain and remove it with a rag. It’s best to work slowly and methodically on small pieces until you gain more experience.