Also known as pipe-grade HDPE, these sheets are about four times more impact resistant than standard HDPE and hold up outdoors, and in wet environments. While other high-impact plastics such as LDPE, UHMW, and ABS can’t be used outdoors, these sheets will not swell when exposed to water. They resist chemicals and contain carbon black, so they will not break down from UV exposure. These sheets are often used to make stub ends, gussets, end caps, flanges, tanks, and containers. Weld them using extrusion, hot gas, and speed tip welding methods and easily fabricate them with standard woodworking tools.