In order to hide sanding marks as well as scratches,
Laying On Polyurethane Is Not Considered The Best Way. Instead of using polyurethane on sanding marks, the best options to do are one of two things mentioned below:
- Wet Sand The Wood: This is the best sanding method that necessitates using water, or some other lubricant such as oil or grease, in order to help get rid of the scratches as you sand, without marking the surface any further.
- Remove The Finish First: Using this method you have to start all over again by getting rid of the scratched-up finish. As soon as the finish is entirely eliminated, and you now have a simple bare wood, start applying a fresh coat of polyurethane.
Now, typically, it is highly recommended to go with method 2 and simply get rid of the finish first before starting all over again. To go for a wet-sanding method, sufficient enough so that the wood surface is evenly and consistently smooth once again is a difficult task. It is very tricky to get that even smooth appearance by wet sanding alone & putting on polyurethane over the marks will not solve the problem.
Two Methods To Get Rid Of Sanding Marks
There are two feasible & realistic ways of getting rid of sanding marks, both of which are mentioned below. Go through these methods carefully in order to solve the problem of hiding the sanding marks, which was not possible by using polyurethane.
- Wet Sanding The Surface: Wet sanding is done with the use of water or some other lubricant such as oil or grease, as you sand. Now, as soon as you start using sandpaper, dust, as well as very small bits of wood, can start to build up below the sandpaper. These dust & small bits of wood are abrasive materials that will make the scratches as well as marks much larger as compared to the grit particle size of the sandpaper grit. The main task of water and/or lubricant is to avoid the grit from building up underneath the sandpaper as you work it over the wood surface. This sanding method leaves behind a much more uniform-looking finish.
- Stripping The Finish: Sometimes, wet sanding will not be able to solve the problem of deep-grooved scratches. In this situation, you have to simply start over again by getting rid of the finish and re-coating. If in case there is only a need to take off a single coat of finish, then you can quickly remove it by applying a chemical paint or varnish stripper onto the wood finish. Wait a few minutes for the polyurethane in order to soften, go through the instructions of the chemical stripper. And then remove the finish with the help of a metal scraper. Go over the wood as long as you have got all the polyurethane removed, and you are down to bare wood. After that, sand the wood again before starting over with a new finish.
How To Get A Smooth Polyurethane Finish Using Sandpaper?
- Start with the help of medium-grit sandpaper of 150, & then sand down the finish.
- Then, proceed onto the 180 grit sandpaper, and sand again as long as there are no 150-grit scuff-marks left.
- After you are done with 150 & 180 grit sandpaper, & marks are still noticeable in the wood, move on to 220 grit sandpaper. Use this to buff over the finish as long as any 180 grit scratches are nowhere to be seen.