Q: I need to know the best way to get rid of swirl marks in the oak hardwood floor that we’re refinishing. I believe we may have used too harsh of a sand paper to start, because we had old shellac that didn’t want to come off. We tried to get rid of the swirl marks and it looked good until we applied the stain. Should we use a drum sander or 4 disc orbital sander? Do we go back to 36 grit, 60 grit, 100 grit, or do we need to start with 120, then 150, 180?
A: First of all I understand your issue with the shellac. It naturally contains wax. When wax heats up it smears. The last one I did was so bad I had to hand scrape the entire bedroom floor before sanding it.
Having said that, when staining the last and finest grit you want to use is 100. Going finer than this and you close the wood surface so much you don’t get any stain penetration. Next, a paper disc, say 80 grit is going to be more aggressive than an 80 grit screen mesh. At this point you have only stained the floor. You want to remove as much of the stain as you can and the scratches. I would probably go with 80 grit paper disc on a polisher or the multi disc machine. Then finally screen the entire floor with 100 grit screen. You can do the edges with an orbital sander, 4″X8″ with 80 grit sandpaper before screening. If there are some scratches that are very deep, you can scrape them out with a hand scraper first before the screening.
If this is a darker color you will have better success if you first water pop the wood before staining. Wet but don’t soak the floor after vacuuming. Don’t miss any spots. This will open the grain and allow deeper, more consistent stain color. Make sure it is dry before staining and don’t scuff your shoes on the floor while staining. If it is a light color you can skip this step.by