Tank forming mandrel with tank bottom mold

A rotatable mandrel comprising a generally cylindrical but tapered shell rotatable about a horizontal axis and providing an outer molding surface for the forming of a sidewall portion of a tank out of thermosetting resin and reinforcing material, a tank bottom or end cap mold adjacent a smaller end portion of the shell for the forming of a bottom or end cap portion of a tank integrally with the sidewall portion thereof, and a plurality of actuators mounted in the shell adjacent the tank bottom or end cap mold in equally arcuately spaced relationship to each other and each having a reciprocable member operatively connected to the tank bottom or end cap mold, the reciprocable members being extensible to free the sidewall portion of a tank from the shell and retractable to abut the smaller end portion of the shell with the tank bottom or end cap mold, the tank bottom or end cap mold having a peripheral flange portion which in effect is an extension of the shell when in abutting relationship therewith.