I got a question about a technique
called rubbing out a finish. I remember doing this to my car as a teenager, but
I've never tried it on a piece of furniture. So I asked the guys at ShopNotes
how it works.
The secret to getting a "perfect finish" isn't how you apply the finish,
they said. It's what you do after the finish dries. That's where rubbing out the
finish comes in. By removing flaws in the finish caused by dust particles or brush
marks, it makes a finish feel smoother. And it improves the look of a finish by
creating a nice even sheen (gloss or satin).
But before you get started, you need to build up the thickness of the finish.
How thick? That depends on the finish and how much sanding you do between coats.
They suggest five or six coats if you're going to use this technique.
Although it may be tempting to rub out the finish as soon as it dries, it's best
to wait a while. By giving the finish time to harden (at least a week, but a month
is better), you're more likely to get a uniform sheen.
When it's time to rub out a finish, the basic idea is simple. You use a series
of progressively finer abrasives to create a pattern of tiny scratches -- just
like sanding a board.
The size of these scratches determines how much light is reflected. So depending
on where you stop in the process, you can get either a satin or gloss finish.
Regardless of the look they're after, they start by wet-sanding the finish with
soapy water and 1000-grit silicon carbide sandpaper. A film of soapy water helps
to keep the sandpaper from clogging. And a rubber sanding block ensures a flat
surface.
The thing to watch is that you don't accidently cut through the finish. So check
your progress frequently, and continue to sand until you get a dull uniform sheen.
Next, to bring out the satin sheen, switch to a powdered abrasive called pumice.
Here again, use soapy water and sprinkle on the pumice (they say a salt shaker
makes a handy applicator). Use a felt block to rub the pumice evenly across the
surface, and then wipe it off.
After you've wiped off the remaining pumice and checked for a consistent sheen,
you may want to use rottenstone to rub the finish to a high gloss. It's applied
the same way. But it makes smaller scratches that create a shinier surface.
Finally, to get a mirror like surface, you can apply a polishing compound and
buff it out. Pumice, rottenstone, felt blocks, and rubbing compound are available
at woodworking stores and from mail order sources.
Go to Tip #22 |
