A cooling tube assembly for operating on a malleable molded plastic part. The tube assembly comprising a porous tube/insert having a profiled inside surface, and a vacuum structure configured to cooperate with the porous tube. In use, the vacuum develops a reduced pressure adjacent the inside surface to cause an outside surface of the malleable molded plastic part, locatable within the tube assembly, to contact the inside surface of the porous insert so as to allow a substantial portion of the outside surface of the malleable part, upon cooling, to attain a profile substantially correspondingto the profile of the inside surface. The cooling tube may include an extruded tube with at least one cooling channel produced by extrusion, the extruded cooling tube may be configured to operate without the porous insert.