This decision is made by determining how the abrasive will be used by the individual. Abrasives are sold in forms such as sheets, large/small discs, belts, and large/small rolls. Selecting the right form is determined by whether the abrasive will be used for hand. sanding, applied to a large disc sander, attached to a small hand grinder, or installed on a large belt sanding machine. Sanding of concave shapes probably requires round or cylindrical shaped abrasives. Flat or convex shapes probably require flat abrasives.
What is the specific surface?
The specific surface means the outer surface of a substance including all accessible pores in relation to the mass. It is determined using the Brunauer-Emmett-Teller (BET) method.