: I have a vibrating sander and it leaves behind small swirls of scratches. The
: scratches are very small and fine but still quite noticeable. It's
: starting to leave so many scratches that its quicker and easier to just
: sand by hand. Any ideas why this is happening?

: Thanks,
: Marie

Hi Marie

It has been my experience that several things can cause this.
1) Buying inexpensive sandpaper or discs will produce scratches as they do not use as good of quality control. The grit sizes vary a little more then good quality paper or discs. Larger sized grit will cut deeper than the rest, leaving scratches.
2) If you are using a square or rectangular vibrator sander, they oscilate at a slower RPM than Random Orbital Sanders. Older models of Orbital sanders also used slower RPM, probably below 10,000 rpm. Newer sanders turn at around 12,000 to 14,000 rpm. The higher RPM tends not to leave the swirls, if using good quality paper.
3) If you let your sandpaper load up it will cause swirls as well. Try to keep fresh paper on it as much as possible.
4) Moving your sander around too much/fast can also counter-act(?) the movement on the orbital and have the same affect as using slower RPM. Moving it around is important, but you have to find a good medium speed so you don't cause flats, but also not cause swirls.

Hope this helps..!

Rehd