Sanding discs, sheets, belts and rolls are the finishing end of metalwork — they blend scratch patterns, prep surfaces for coating, and remove material where a grinding wheel would be too aggressive.
Backing type determines how the abrasive is mounted. PSA (pressure sensitive adhesive) discs stick directly to a backup pad. Hook-and-loop (Velcro) discs are faster to change and reusable. Fibre discs have a vulcanised fibre backing and are the toughest, used for heavy blending and weld removal on angle grinders. Cloth backing is used for belts and for discs that need tear resistance.
Grain follows the same logic as other abrasives: aluminium oxide for general work and wood, zirconia for steel, ceramic for hard alloys and stainless, silicon carbide for non-ferrous and painted surfaces. Grit progression from 36 to 400 covers the range from stock removal to final finish.
Disc diameter and arbor size must match the tool. A 5 in disc on a 4.5 in grinder is not covered by the guard; a disc with the wrong arbor hole will not centre and will run out of balance. Speed rating must also match the tool's RPM.
