Jun 10, 2022 · Giveaway HOBBY hdpe sheets st-HDPE sheets 4×8, Custom HDPE 2022-06-10 High Density Polyethylene (HDPE) Sheet. This sheet can be heat formed, shaped, and welded to fabricate ducts, hoods, and much more. The material cannot be cemented, but it is easily welded with a plastic welder.