Soundboard for Guitar - Molded Plastic Composite Top with Integral Reinforcing Ribs

This patent describes a molded plastic guitar top (soundboard) made from a thermosetting plastic sheet molding compound comprising approximately 40% glass fiber and 60% resin. The soundboard features a circular sound hole with concentric annular reinforcing ribs and rectilinear ribs extending longitudinally toward the lower end of the guitar, all projecting from the inner surface of the sounding board. The design incorporates long random glass fibers (3 inches to 2 feet) in the sounding board mat and shorter chopped glass fibers (not greater than one-half inch) in the reinforcing ribs, providing high stiffness, resistance to temperature and humidity changes, and uniform sound-producing qualities.