An asymmetric mold core and method for use for forming curved floor openings in pallets is taught. The mold core contains: a base, the base attachable to a frame in a rotomold, a bottom section integral at a distal end to the base, and a top section integral at a distal end to the base. Both the top section and the bottom section have convex radial curve shape, but the top section curve and the bottom section curve are positioned by having different centers of rotation so when the core is actuated it is only actuated around the center of rotation about the bottom curve which causes the top cure to drop away from the upper molded surface.