Abstract: Thin wall lightweight panels which are subjected to high temperature solutioning and rapid quenching to impart high strength properties without distortion, warping or oil-canning. The panels are produced by casting in a mold cavity having an interconnected recess network which surrounds thin wall-forming areas and distributes molten metal uniformly thereto. The recess network forms a waffle pattern reinforcing rib network surrounding the thin-wall areas, lending strength and dimensional stability thereto during the heat treatment and quenching steps, to prevent distortion, warping and oil-canning.