Metalworking, Rough Grinding; 80 Grit; Y Weight; 10 Belts/Pkg; Resin Bond Polyester Backings Closed Coat This closed coat zirconia alumina belt uses a heavy "Y" weight resin bond polyester backing with grinding aid for a fast cut in heavy grinding, deburring applications. It is suitable for cast iron, nickel, alloy and stainless steel requiring sharp cutting without heat build-up.. Zirconia alumina is a man made abrasive and its products are typically in green or blue color. A blocky shape grain has a micro-crystalline structure. Zirconia alumina's self-sharpening characteristic gives good life on heavy stock removal applications, i.e. heavy grinding of metals, planing operations for wood. Resin Bond Backings - Resin bond backings offer greater resistance to heat , are more durable in heavy stock removal applications and provide the best all-around bond system.