Wood Finishes – How To Get a Smooth Wood Finish
Achieving a smooth wood finish takes a few steps. Each step in turn will provide a new level of smoothness and consistency to the final finish.
In order to completely refinish wood, you’ll need to sand away the old finish. Even if the wood is new or has been chemically stripped, you’ll need to sand it so that stains and finishes can properly sink into the wood. However, sanding creates small bruises in the wood. In order to minimize these, sand the wood until it is smooth.
Sandpaper’s roughness is measured in grits, the term used to describe the rough granules that make up the sandpaper. The higher the grit number, the finer the sandpaper.
In order to get a smooth wood finish, you’ll want to start with a low grit, like 80 or 100. This will leave the wood rough, but it takes away imperfections and finish faster. You go progressively finer in order to remove some of the roughness left by the coarser grit.
After the roughest level, go up to 120 or 150 grit sandpaper and then 180 grit sandpaper. By the time you are done with 180 grit sandpaper, there shouldn’t be any visible scratches left.
For most finishes that is enough. Additional sanding will make it more difficult for them to penetrate the wood. However, oils require even smoother wood, since they cannot be sanded in between coats.
In order to gain the smoothest wood finish, use a sanding block if you are hand sanding. This will spread out the pressure so you cannot create a deep indentation in one place and almost no sanding elsewhere. You should also vacuum and brush away dust every so often. This will get rid of anything that might fill the sandpaper and make it less effective.
Once the sandpaper begins to be less effective, refold it to expose a different part of the sandpaper. Eventually, you will need to replace the sandpaper in order to continue sanding down the wood. This will result in a smoother wood surface.
For best results, always vacuum in between using different grits of sand paper. Some of the coarser pieces of grit can remain behind on the wood and continue to gouge the wood if they aren’t removed.
Sanding in between coats of wood finish.
If you are using any film forming clear wood finish, polyurethane or varnish, you need to sand in between the coats. This will remove any stuck dust or missed roughness from the initial sanding.
Most surfaces are best sanded with a fine sanding sponge after the first coast of finish has dried. This is a light sanding or buffing to produce an ultra smooth surface. Do not sand through this coat of finish, just dull the existing finish.
After this sanding use a vacuum to remove most of the dust then wipe the surface with a tack rag. Now apply another coat of finish.
Applying Your New Wood Finish
Application technique also has an effect on the smoothness (feel) and final look of wood finishes. Use these basic suggestions to get a smooth wood finish.
- Spraying will always provide the smoothest wood finish but has its drawbacks. Using an HVLP sprayer (cup gun) is slower but you get great control but it will take more coats. Using an airless sprayer is faster and less coats but more chances for runs, applies thicker coats.
- Many good wood finishes are available in spray cans. These are perfect for small projects and do a good job.
- If brushing use the finest bristles possible. Example- using an ox hair blend brush when applying oil base wood finishes will produce the smallest brush marks.
By following these tips, you will be able to get a smooth finish. Slowly and thoroughly sanding the wood down with progressively higher grits will smooth out the surface. In addition, using a sanding block, cleaning the wood, and knowing when to replace the sandpaper will give you the smoothest wood finish.