3M™ fiber 501C is a versatile and general-purpose metalworking abrasive, designed to help with a variety of applications from grinding, weld removal & finishing to blending on metals like carbon steel. 3M™ fiber 501C engineer by adhering alumina zirconia mineral to a fiber backing using resin. The closed coat construction on 3M™ fiber 501C means mineral grains cover nearly 100% of the backing. The stiff fiber backing is extremely durable - vulcanized, hardened and condensed prior to being-coated with mineral. It withstands wear and tends not to yield or deflect when run, which helps the abrasive stay strong, especially when grinding and finishing on edges.