a method of manufacturing hollow , fiber reinforced thermoplastic composite articles , such as a pressure vessel , is disclosed . the thermoplastic binder is chosen to bind the reinforcing fibers together , to provide strength , and to provide ease of manufacture . the method includes placing a preform with an inflatable core into a mold , pressurizing the inflatable core , and heating the mold to enable the thermoplastic binder to melt and distribute throughout the preform , binding the reinforcing fibers . the article is then cooled and removed from the mold , resulting in a hollow molded article . the inflatable core may be removed from the article and reused , or the core may become an integral part of the finished article .