Stringed instruments: In 1985, RK Carbon fibers was involved in the utilization of carbon fiber for the production of the necks of guitars using a novel expanding core technique. This entailed wrapping the expanding core with prepreg and carefully stacking the rolled sheets in prescribed positions in a mold, which was then heated. The core, when heated, expanded by about 50%, forcing the material into all parts of the closed mold, a web forming at the point of contact of each wrapped roll. The core material was formulated from cork granules, phenolic micro-balloons and epoxy resins blended together with curing and blowing agents give the requisite viscosity. The moisture in the cork and the N2 evolved from the blowing agent were sufficient to ensure adequate internal pressure to consolidate the lay-up within the mold, forming a lightweight foam core.
Ovation Guitars were created by Charlie Kaman, a man with a background in aerospace, who developed the roundback guitar based on the structural arch, with the aim of providing rigidity without the need for braces inside the guitar. The shape was designed to reflect the sound towards the soundhole to give better projection and improved volume. Some 20 years ago, Ovation introduced the first carbon fiber top making it half the weight of a spruce top and many times stronger.
Modulus Guitars, in their Genesis range, uses a compression molded carbon fiber element to improve load carrying capacity of the neck of resonant tone woods.
Rainsong claim that 99% of the sound of a guitar comes from the top. Damping gives a guitar its tonal character and a carbon fiber/epoxy soundboard has almost constant damping across the acoustic spectrum rather than increasing rapidly at higher frequencies. The guitar also posses the ability to produce louder trebles as compared to a wooden guitar. In an effort to reduce the weight of the soundboard, Rainsong have eliminated traditional soundboard bracing.
Kuau Technology of Havaii’s Rain Song guitars claim that carbon fibers do not absorb high frequencies, whilst aramid fibers dampen unwanted tinnniness.
The Zeidler Carrera mandolin uses a stainless steel truss rod with additional carbon fiber reinforcement.
Bows for cello and violin: Spiccato Bows and Coda Bows are companies that manufacture carbon fiber bows. The carbon fiber stick does not change in length with temperature, humidity or altitude and one of the models can be adjusted to allow the player to change the flexibility of the stick according to personal taste.