If you are having an issue getting the final finish to lay down just right, these tips can help you finish your project and make it the envy of your friends and neighbors.
There are myriad causes for poor appearance ranging from dust, wood fibers, rushed application, bugs, bubbles, streaks, etc., but the cure is almost always the same.
While sanding, scuffing or buffing is rarely REQUIRED, it can sometimes help achieve a pristine final finish. This guide will detail how to fix problems with Waterlox Film forming finishes (Original, Urethane, Marine and H2OLox).
The key is to save this procedure for the end before your final coat (or even after your final coat in some instances, but we’ll get to that later). Doing this after your initial coats may just reopen that wood surface that we are trying to seal and cause our issue to reemerge (i.e. wood fibers, “micro bubbles”, shiny spots). Once we have a few coats on, then the sanding/buffing/polishing process will be done on the Waterlox film layer and not on the wood underneath.
Ensure you have enough product on the surface.
We want to be dealing with the Waterlox film and not the wood substrate. Your project should have a nice even gloss over the entire surface and there should be no dry or “starved” areas in the wood. This shows you have a good continuous film. In general, this would be at least 2 healthy, brushed on coats on anything red oak or harder, or 3 healthy, brushed on coats on softer woods like pine, fir, walnut, etc. See Number of Coats for your Project for more information.
Gather the proper materials.
For a smaller project (countertop, table top, vanity, etc.):
- Sanding block – Used to hold sandpaper flat. Can be done by hand, but the block makes it easier to just glide over the surface. We do not recommend the use of power sanders as these would be too aggressive.
- 320-400 grit sand paper – Used on the block to knock down the major bumps, blemishes and imperfections. Coarser paper may leave scratches in the film that are visible to the eye, finer paper may cause too much heat and may gum up the paper making it less effective.
- 0000 steel wool or a maroon scotch brite pad – This is to lightly polish out the scratches from the sandpaper and helps to ensure a good, even surface.
- Mineral spirits/paint thinner – Lubrication for the sanding process will help reduce the aggressiveness of the abrasives to minimize noticeable scratches and keep dust to a minimum. You can also use some lightly soapy water, but you’ll need to immediately rinse the surface off with some clean water and wipe dry when you are done buffing.
For a larger project (i.e. floor):
- You can use the same materials, but more common would be to use a maroon scotch brite pad (a.k.a. SPP or Surface Preparation Pad) or other lightly abrasive pad on a floor buffer (round or square buff). This would replace the paper and steel wool steps. You can also do this by hand and just do spot treatments if necessary. See below floor buffer tips.
Fix the major imperfections.
After allowing at least 24 hours for the previous coat to dry, you’ll use your sand paper on a block with some mineral spirits for lubrication to lightly sand the surface. This should be done by hand and should really only take 8-10 passes with little to no pressure. For added security, always sand in the same direction the grain ‘runs’ down a board wherever possible. When you are done, you’ll most likely see little dull spots throughout the surface where you removed a bump, but most of the surface should still be glossy.
Buff the surface and remove the scratches.
Follow your sand paper procedure by hand buffing the whole surface with 0000 steel wool, again with mineral spirits for lubrication. This should also be done with little to no pressure and should be done over the entire surface. This will leave a very fine scratch pattern that is not discernible to the eye, so you do not need to go with the grain with this process.
For the larger projects using the floor buffers, you can just lightly buff the entire surface with the slightly abrasive pad. This should just be a quick buff as you are not looking to remove a lot of material, but you are just knocking down the big offenders. Vacuum and sweep up any dust from this procedure.
Wipe the surface clean with a clean lint free cloth, very lightly dampened with mineral spirits. This will pick up all the material from the pores and slurry from buffing and should restore the clarity.
At this point you should have a very smooth, consistent surface. You can now apply your final coat from a great starting point! As mentioned earlier, you can do this after your final coat as well. This will leave you with a nice, satin luster. If you are going to leave your project as finished at this point, it is best to start with an extra coat because you are going to remove some extra material. Therefore, do this after your 3rd or 4th brushed on coat of FINISH. That way you are not sacrificing your protection by potentially having too thin of a layer after sanding.
You can do this procedure with any of our Original products or Urethanes. If you are struggling with a streaky satin finish, you can just follow this procedure and leave it as is and you should have a very nice satin sheen. For smaller projects, continue to polish the surface with finer abrasives to restore clarity. Pumice stone and rotten stone are excellent for this.
If you already have a lot of coats on and you are worried about applying too thick of a film, your final coat can just be a thin wiped on coat. All you are trying to do is to fill the scratches from the fine abrasives, so it will not take much product.
If you are going to apply one more finish coat, rub your hand over the surface and feel for any imperfections. It should be very smooth and you should not pick up any dust on your hand. You can always buff a little more if needed.