extra_info

What is grit?

When talking about sandpaper ‘grit’ is a reference to the number
of abrasive particles per inch of sandpaper. The lower the grit the rougher the
sandpaper and conversely, the higher the grit number the smoother the sandpaper.

This make sense if you imagine how small the particles on an 1000-grit sandpaper
would need to be to fit into a 1′ square (25,4mm square). Sandpaper is referred
to by the size of its grit (Example 120-grit sandpaper or P120
sandpaper).

Choice

You need to choose the grit size of sandpaper depending on the particular job
you are trying to accomplish. For heavy sanding and stripping, you need coarse sandpaper
measuring 40- to 60-grit; for smoothing surfaces and removing small imperfections,
choose 80- to 120-grit sandpaper. For finishing surfaces smoothly, use a super fine
sandpaper with 360- to 600-grit. Many jobs require you to “go through the grits.”
This means you start the project using lower-grade grit and use finer pieces of
sandpaper as you progress. Each time you advance to a higher grit sandpaper, you
remove the scratches from the previous layer.