When it comes to choosing a grit size, it helps to have a mental image to guide you. The following explanation is a “quick and dirty,” non technical, simple and easy explanation.
First, know that our ANSI grit sizes will match sandpaper grits in a hardware store. So a 60 grit sandpaper will have particles very similar to our 60 grit loose abrasive – regardless if it is a silicon carbide or aluminum oxide. If you prefer to view a physical representation, go to a hardware store and take a close look at the particles on a variety of sandpapers. You will see for example, that a 600 grit sandpaper has very fine particles imbedded in it, whereas an 8 sandpaper has coarse, larger particles.
Second, imagine you held a small 1″ x 1″ square piece of mesh (screen material) in the palm of your hand. An 8 grit will pass through a screen with 8 holes in that 1″ square mesh. A finer 240 grit will pass through a screen with 240 smaller holes in the same 1″ square mesh. In other words, the finer the particle size, the smaller the holes must be on that 1″ square piece of mesh for particles to pass through, and that means there will be lots more holes in the mesh.
Bottom line: An 8 grit is much coarser than a 360 grit. Low number = coarser grain size. As grit size increases in grit number, it decreases in physical size, becoming finer and finer until we are dealing with polishing powders.
We sell sandblasting grits and powders online in a variety of different abrasive medias.