| Of
all the activities involved in furniture making, sanding has
to be the least popular. It's always messy and irritating, and
usually tedious and frustrating. This is true for the beginner
and expert alike and probably is the result of nothing more
sinister than bad timing. After spending so many hours in
stock preparation, joinery and assembly, most of us just want
to get on with the finishing so we can see the piece come
alive. Unfortunately the road to a good finish passes through
a lot of sanding.
The most common abrasive material is sandpaper. It's
generally sold in full sheets that measure 9 x 11 in. It's
also available in discs and belts of various sizes to fit both
portable and stationary sanding equipment. But for the
beginner, the flat sheets are all you need.
Sandpaper is manufactured with various abrasives on the
surface, each with a preferred use. Garnet paper is a fast
sanding variety that's best suited to working by hand.
However, it's not terribly durable. If you plan to use a palm
sander, like the one we show in our basic toolbox, you'll need
a longer lasting, tougher abrasive. Aluminum oxide paper is
the best choice for this application.
When it comes to the finishing stage of your project when
you need to sand between finish coats, silicon carbide paper
is the best bet. It holds up especially well in the finer
grits.
All of these sandpapers are rated by the coarseness of
their abrasive particles. You can find papers ranging from a
very coarse 40-grit up to an extremely fine 1500-grit. But for
general work, grits that range between 100 and 320 will do the
job.
Sandpaper is also classified by the type and weight of its
backing material. Both paper and cloth are used for this
purpose, but paper is by far the more common. When you look at
the back of a sheet of sandpaper, you will see a code
describing the grit of the surface and the weight of the
backing. The weights are classified from A to X, with A being
the thinnest and most flexible backing. For hand sanding,
A-weight paper is appropriate, and for an orbital sander,
C-weight paper is best.
Finer-grit papers are also available with water-resistant
backings. These are usually classified as wet/dry abrasives.
They're most often used to level finishes like varnish or
lacquer, before the final polishing. In wet sanding, water is
used as a lubricant to keep the paper from clogging.
The general sanding rule is to move from coarser to finer
grits in sequence, until you reach the desired finish. For
most applications, you should start sanding with 120-grit
paper. This should remove any scratches or other defects, like
subtle planer marks, from the surfaces of the wood. But if
your stock is particularly rough with pronounced, clearly
visible planer marks, then you should start with 100-grit
paper. In rough conditions, you can also save a lot of tedious
sanding time by first lightly hand planing the surface. | 
