A process, and the product thereof, for making a composite vessel having at least one closed end, the process including the steps of: fabricating a
thermoplastic liner for the vessel; overlaying onto the liner a layer of commingled
fiber and
thermoplastic material to obtain a composite
intermediate structure; pressing and heating the composite
intermediate structure to effect at least partial consolidation in apparatus which includes upper and lower
silicon rubber bags, the bags having dimensions such that, during operation, their facing
peripheral regions abut to encompass the composite
intermediate structure; then placing the composite intermediate structure in a mold; heating the composite intermediate structure in the mold while applying a force, such as internal
gas pressure, tending to urge the composite intermediate structure against and into the shape of the interior walls of the mold until the
thermoplastic liner and the overlaid layer fully consolidate; cooling the mold and composite vessel until the composite vessel is solidified; and removing the formed composite vessel from the mold. The commingled
fiber and thermoplastic material may either be wound onto the liner or laid on the liner in the form of fabric woven from the
fiber and threads of the thermoplastic material.