Abstract: A stringed musical instrument body is formed using injection molded high density polystyrene foam with a foaming agent. It is injection molded by itself or around a wooden core to make the body or to form two panels adhered together to sandwich a wooden core therebetween. The core provides good wood tone and the polystyrene with a foaming agent produces good sustain and a resonance of about twenty-eight seconds. A metal reinforced injection molded neck resists warping.

Abstract: A stringed musical instrument body is formed using injection molded high density polystyrene foam with a foaming agent. It is injection molded by itself or around a wooden core to make the body or to form two panels adhered together to sandwich a wooden core therebetween. The core provides good wood tone and the polystyrene with a foaming agent produces good sustain and a resonance of about twenty-eight seconds. A metal reinforced injection molded neck resists warping.

Abstract: A stringed musical instrument or guitar has a plastic foam body substantially covered by a shell of thermoplastic material, a wood base on the plastic foam body, a plurality of strings supported to extend above the wood base, and at least one electromagnetic pick-up at the base. Musical vibrations produced by strumming the strings are conducted via the plastic foam body and wood base are largely sensed by the electromagnetic pick-up.

Abstract: A guitar has a hollow plastic body including spaced front and back panels, and a foam plastic core disposed between the panels, whereby upon vibration of the panels air trapped within the individual cells of the foam core are alternately pressurized and depressurized, thus to enhance the musical output of the guitar.