Acoustic Guitar Made of Carbon fiber and Epoxy Resin Developed

John Decker, has developed an acoustic guitar made of carbon fiber and epoxy resin. He started a company called RainSong Graphite Guitars that produces about 700 all-composite guitars a year.

Creating a guitar sans wood that would be durable and sound good was a challenge for Decker and his colleagues. The "sound" of a guitar depends on what the soundboard - the top butternut squash-shaped panel - is made of. Traditionally, soundboards are made from a wood like spruce or cedar. Decker and his colleagues experimented first with other materials like fiberglass, which was too heavy, and plastic, which was too flexible. They settled eventually on graphite because its fiber structure was similar to that of wood's and would hopefully mimic the tonal qualities of wood. They experimented with adding other fibers and the proper amount of resin until they got a soundboard that worked.



On the RainSong website, Decker uses physics to explain what gives the RainSong guitar its unique "carbon sound". The soundboards on guitars transfer the vibrations of the strings into sound which then resonates in the body. For wood, about half of those vibrations are absorbed and turned into heat instead of sound. This effect, called damping, is heightened at higher vibration frequencies.

Graphite, however, doesn't have the same damping properties as wood and the higher notes don't fade away as quickly on a graphite guitar as they do on a wooden one. The graphite is nearly linear and each of the frequencies is damped at almost the same rate. This results in louder treble on the graphite guitar. The linear damping also gives the guitar purer tones by reducing the mixing of harmonics that happens when playing a wooden guitar.