Silicon carbideis usually used to sand a hard finish that has been
applied to a piece to level it out. An example of a hard finish would be
polyurethane, which we’ll talk about later. Silicon carbide is easy to
distinguish from other sandpaper because of its black color. The glue
used to apply the silicon carbide to the paper is waterproof. This means
that it can be used to sand a finish that is still wet. Usually Silicon
carbide is used just in the finer grits.
With grits from 60 to 1200 and up it would take all day to sand a small
project if we used every one available. Good news! You usually only
needs to use a few to get the results you’re after.
Which Grits to Use
Deciding on the first grit to start with is hard. The first grit needs to be
coarse enough to scratch out the worst marks on the wood but not too
coarse that it ends up causing more damage to the wood than the marks
you’re trying to remove. Usually 80 to 100 grit is a good place to start.
The only way to know for sure is to start out with one and if it doesn’t
seem to be removing the marks on the wood without a lot of effort step
down to the next grit. Now, the next grit doesn’t have to work as hard as
the first. All the next grit has to do is remove the scratches left behind by
the last grit used and so on. Grits to normally use are: 80 or 100 then
120, 150, 180. In most circumstances, grits over 180 are used to polish or
level an existing hard finish.How to Sand
When sanding a flat surface
you need something flat for
the sandpaper to be placed
on. The simplest thing to
use is a block of wood. A
piece of wood that is about
1”thick 2 ½” deep and 3 ½”
long will work great.
Chamfer the edges with
your block plane so the Sandingblock