Abstract: An improved method for forming a hollow core structural member, such as an automotive bumper beam, from moldable plastic sheets, such as fiberglass reinforced plastic sheets, by providing a press having a desired shape on the opposing members of the press, placing opposed sheets in the press with a layer of frozen, meltable material, such as ice, in place between them, forming the sheets into the desired article configuration in the press, removing the formed member from the press, then melting and removing the meltable material from the interior of the formed member.

Abstract: A double-walled, plastic, structural body panel for motor vehicles, such as a door or tailgate, comprises an outer part and an inner part, both preferably injection-molded of a thermoplastic synthetic material, which are joined together along edge areas. Both the outer edge areas (4) and the inner edge areas (5) have adjacent flat joining areas (7/8 and 9/10, respectively). A web or flange (11 and 12, respectively) extends approximately at right angles to the adjacent flat joining areas. An adhesion coating (6) or an adhesion welding joint is formed at the adjacent flat joining areas.