Orbital sandersanding so you need to know how to do it correctly, besides orbital
sanders really are best used on flat surfaces only and they’re a lot more
expensive than a sheet of sandpaper.
So why do we need to sand
the wood, especially if we’re
not going to put anything else
on the piece like paint, wax,
etc...? The problem is that all
tools used in cutting or
shaping wood leave their
marks. You may not even
notice it at first until you pick
it up and feel unevenness in
places or the light hits it in
just the right way and you see
saw marks. If all that doesn’t
convince you get two pieces you’ve built, sand one and leave the other
untouched. You be the judge of which one looks better! And the tool
marks will be even more obvious if you use a finish, which will highlight
once unseen flaws.
Types of Sandpaper
Sandpaper is made up of abrasive grits that are glued to a piece of paper.
These grits are designated with a number. Lower numbers mean a
coarser (rougher) grit; higher numbers use smaller or finer grit. There
are three types of grit that you’re likely to see in stores: garnet,
aluminum oxide, and silicon carbide.
Garnetis a natural mineral and is the less expensive but the quickest
wearing of the three. Garnet comes in grits ranging from 80 to 220.
Aluminum oxideis a man-made abrasive. It is more expensive but lasts
longer so the extra expense may be worth it. Aluminum oxide comes in
grits ranging from 80 to 1200.