Q & A: Sanding Scratches Revealed

Q:

What can I do to see sanding scratches before I apply stain?
I always miss some of them until it’s too late.

A:

Doesn’t that drive you crazy? Just when you should be
home free, wham! Now you’re stuck with a lousy finish
and there’s no way out.One simple measure can prevent this
from happening again. Use a bright light to make the
scratches visible before you stain.

A portable trouble light held at a very low angle to the
wood makes sanding scratches stand out like long shadows
at sunset. This raking light is the ultimate test for a wellsanded
surface.You may see random orbit sander swirls that
you never knew existed.

Check your progress with the light between each grit of
sandpaper. As you move from coarse to fine paper, the
trick is to remove all the scratches made by the previous grit.
The only way to ensure that you’ve succeeded is to actually
see the scratches, and that’s where the light comes in.

Click any image to view a larger version.

Unwanted scratches pop
out under a low-angle light.

This story originally appeared in American Woodworker August 2001, issue #88.

August 2001, issue #88

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