Backing Pad (4.5-inch)

A 4.5-inch backing pad for an angle grinder. Fibre sanding discs have no rigidity of their own, so they need a pad behind them: the pad screws onto the grinder spindle, the disc goes over it and is held by a nut, and the slight flex of the pad is what lets the abrasive follow a curved or uneven surface instead of digging in at the edge. That turns a grinder into a sander, which is how most people in the trades actually sand steel - stripping paint and rust off gates, grilles and vehicle panels, blending welds, feathering filler, and cleaning up concrete and timber. Match the pad diameter to the discs you buy, and replace the pad once its face has gone hard or ragged.