3M™ Fibre Disc 581C features an alumina zirconia abrasive on a fibre backing that’s closed coated and resin bonded. Our discs offer a good performance, consistent quality finish and are packaged on a reusable disc clamping system, for easy storage and retention of disc shape and form.Use 3M™ Fibre Disc 581C for a good performance and consistent quality finish. Our discs are packaged on a reusable disc clamping system, for easy storage and retention of disc shape and form. They’re made of an alumina zirconia abrasive on a fibre backing that’s closed coated and resin bonded.581C discs are ideal for grinding and finishing weld seams on all metals.