Abstract: Reinforced thermoplastic polymer composite sheets are formable into smooth, shaped objects in a rapid stamping process in a cool mold when pre-heated outside of the mold. The characterizing constituents of the composite sheet are: (1) thermoplastic resin, (2) relatively short reinforcing fibers, (3) relatively long or continuous glass fiber, and (4) a particulate loading agent. This four-component system, laminated together, produces sheets having excellent formability, mechanical properties, uniformity and in particular surface smoothness not heretofore obtainable, and are simple to fabricate continuously.