Sandpaper
Never carve when you can saw
Never sand when you can carve
Sanding actually takes very little time if you select the right paper and
select the proper block for the job.
It
is important to purchase good sandpaper. As far as I am concerned, 3M
Sandblaster paper is the best sandpaper available bar none. Norton
sandpaper is also excellent and generally a little bit less expensive than
3M.
I have been using
Sandblaster paper for the past few years. From the first time I used it I
could tell the difference in how it cuts the wood. That is what
sandpaper does, by the way. It is little pieces of grit adhered to a
backing that cuts away material.
Sandpaper comes in a variety of types. I do not consider sanding to be a
chore. Because most people do, selecting the correct sandpaper for any
given task will lessen the
pain they have to endure.
Apparently aluminum oxide will chip during use so that it
stays sharp longer.
According to a now defunct Woodzone link, garnet paper does not have this property
and so doesn't last as long.
Garnet paper will provide a better finish which I can confirm. I
have used both types of sandpaper and prefer garnet over aluminum oxide.
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Wet or Dry sandpaper is designed for non-porous surfaces. It is
good for sanding paint, fiberglass, metal, etc. Finer grades are good for
finish-sanding balsa wood.
Garnet paper is made for wood and what you should buy.
Flint paper is for kids at
summer camp and should never enter your shop.
Aluminum Oxide paper can be used for wood or metal. See sidebar
for more information.
Note that Garnet and Flint papers are not water proof. In fact, I live
in Florida and my shop is not climate controlled. During periods of high
humidity, my sandpaper absorbs enough moisture from the air that it wears out
very quickly.
I buy boxes of the
grades I use most often (220 and 360) in larger quantities and 5 packs of 80 and 150 grit because
they tend to last longer when used on soft
balsa wood.
I buy the assortments of Wet or Dry paper
because they last a long time as well if I take care of them. The pieces I use for wet sanding
are rinsed thoroughly and then hung up to dry using clothes pins. When I come across very fine Wet or
Dry paper (finer than 1000 grit) I usually buy several pieces because it can be
difficult to find.
There are polishing kits available for taking scratches out of clear plastic
(motorcycle windscreens, for example) that come with very fine grades of
sandpaper — 12,000 grit amazingly enough. It is cloth backed and good for
taking imperfections from clear plastic parts —
usually canopies. A 12" x 12" sheet of this paper is almost $15.00, but
the kits contain a variety of grits in smaller sizes. It is worth
purchasing one of the kits if you want to have scratch-free canopies.
To accomplish your work faster and use less
sandpaper it is important to learn
when and why to use which grade. A common mistake is starting
out with too fine of a grade. This is the main reason people think
that sanding takes a long time. If the first paper you use is 400 grit,
then it will take forever to flatten a part or even get it close to being
finished.
Generally speaking, coarse papers are used for rough shaping
and flattening. Medium papers are used for final shaping and
removing scratches from coarse papers.
For bare wood that will be covered, fine paper is an acceptable stopping
point. However, even wood as soft as balsa can be polished. This is
where ultra fine papers come in.
Do not switch grits until the paper you are using has removed all the
scratches from the previous paper. For example, if you start with 100 grit
and then move to 150 grit, do not switch to 180 grit until all the 100 grit
scratches are gone.
If you move to a finer grade before completely removing the scratches of the
previous grade, you will either do too much work to remove the scratches or have
scratches left in the wood.
You do not need to move progressively through each grit in most cases.
Again, experience will be very helpful to you in knowing when to stop with one
paper and what the next one should be.
When you begin using fine paper, you should be finished or very close to
finished shaping the part. At this point you are preparing it for the
final finish.
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