chemicals when applied under sufficient temperature and or pressure the melt processible thermoplastic fluoropolymer film can act as an adhesive to adhere the high strength porous expanded ptfe film to the surfaces of other materials the expanded layered composite film is wrapped on the core of elongated ptfe so that the thin layer of melt processible thermoplastic fluoropolymer contacts the core of elongated polytetrafluoroethylene the composite film layer is then heated to cause the thin layer of melt processible thermoplastic fluoropolymer to at least partially melt and adhere to the core of elongated ptfe core and or the previous layer of film the ptfe film may be wrapped on the core in any desired manner for instance the film can be wrapped on the core helically so that the film forms a helical seam on the composite gasket material alternatively the high strength film may be wrapped on the core in a longitudinal manner so that the film forms a longitudinal seam on the composite gasket material while the film may be wrapped on the core by hand it is preferred that the wrapping is accomplished through the use of high speed mechanical wrapping apparatus such as a conventional tape wrap machine used to wrap dielectric tape layers on conductors one such machine is disclosed in u s pat no 3 756 004 to gore the tape wrap machine applies a degree of back tension to the high strength film as it wraps it in a helical fashion around the core which applies a compressive force to the core and thereby somewhat densifies the core in the process the degree of back tension applied to the high strength film may be varied so that the density of the core and final dimensions of the assembly may be controlled ideally.