a molding apparatus for making molded plastic skins includes a housing shell , and a mold shell which is movably supported on the housing shell for movement thereto and has a wall which is determinative for shaping the contour of a plastic skin . the mold shell and the housing shell define together a hollow space for throughflow of a heat - transfer medium . flow passageways for heat transfer medium may be provided by subdividing the hollow space between the mold shell and the housing shell by means of partition walls to thereby force the heat - transfer medium to flow along a predetermined path .