Abstract: A selectively-flexible, selectively-rigid, reusable, one-piece mold is used to fabricate a composite part having a complex shape on an outer surface of the mold. Disposed within the interior of the shell is a grid-type support truss structure having a plurality of individual support members attached at one end to headers that are attached by clips to the inside surface of the shell at predetermined locations. The support members are locked in place relative to each other by the use of pins placed in holes formed at various locations in the support members. When locked in place in this manner, the shell is stiffened, thereby facilitating the fabrication of the composite part on the mold. When the pins are removed, the shell is allowed to flex, thereby facilitating the removal of the cured composite part from the outer surface of the mold.