2 lor HDPE sheets . HDPE sheets 4×8 . UHMWPE boards Home » News » HDPE sheets 4×8 » 1.5 inch high density plastic board st Australia. High Density Polyethylene (HDPE) Sheet . The material cannot be cemented, but it is easily welded with a plastic welder. It can be cut with a carbide-tipped saw blade and drilled with regular metal bits.