Flashing (weatherproofing) bark was occasionally used as a flashing material. Most flashing materials today are metal, plastic, rubber, or impregnated paper. Metal flashing materials include lead, aluminium, copper, stainless steel, zinc alloy, other architectural metals or a metal with a coating such as galvanized steel, lead-coated copper, anodized aluminum, terne-coated copper, galvalume (aluminum-zinc alloy coated sheet steel), and metals similar to stone-coated metal roofing. Metal flashing should be provided with expansion joints on long runs to prevent deformation of the metal sheets due to expansion and contraction, and should not stain or be stained by adjacent materials or react chemically with them.
Coated abrasive sanders, die grinders and belt sanders The first recorded use of a coated abrasive is from the 13th Century, when the Chinese bonded crushed sea shells to parchment using natural gum. A quick change system is commonly used with disc type coated abrasives. A plastic or metal hub is bonded to one of the faces, which is threaded. This then mates directly to the sander/grinder or to a mandrel that can be mounted in a sander, grinder, or drill. The advantage is that the disc can be quickly replaced when needed. Quick change discs range in sizes from to no