Kaman (pronouced like Command without the D) was not happy that the Martin dreadnaughts neck needed a reset and the body was cracking. He decided to build a better guitar.
Josh White Model
Using the same technology his company specializes in to create aerospace and satellite parts. Kaman came up with the idea of creating a guitar out of these materials. His first utilized a spruce top, a maple neck with a center strip of walnut and a unique fiberglass bowl-shaped back made of a composite material the company used in creating helicopters. The composite was trademarked as Lyrachord. Of course we are talking about the Ovation guitar.
In 1976 Kaman took this a step further with the creation of the Adamas guitar.
The Adamas had the same round Lyrachord bowl back. What was quite unique to the Adamas was the instruments top. It utilized long strand carbon-graphite fiber. This material allowed the top to be much thinner than spruce, but as the company claims "with the same vibrating qualities of spruce. Due to the decreased mass, the vibration was intensified therefore able to vibrate louder and longer. "
The Adamas website also states; "The top is actually a composite structure, with two .005" carbon-graphite outer layers and a .035" birch veneer sandwiched in the center, bonded together at 250° F. While the fibers of the carbon run in a longitudinal direction parallel with the neck of the guitar, the birch veneer grain is set to a 60° angle to the carbon."
There is an extremely light finish applied as to not inhibit vibration.
To prevent torque issues associated with the pressure of string pull, the soundhole was relocated from its usual center of the instrument to the upper and lower bouts in the form of 22 individual soundholes (15 soundholes on cutaway models.)
Traditional guitars use a series of wooden blocks to bind the top and back of the instrument to the sides. This is called kerfling. Because of the construction method of Adamas, kerfling was eliminated and replaced with a flexible ring on the inner top and bowl of the instrument. Of course due to the parabolic design of the bowl back, which acts as a orchestra shell, there is no need for kerfling since the bowl is molded.
The RainSong Guitar Company was formed in the 1990s by Dr. John Decker. Decker was living in Hawaii and concerned about string instruments warping due to the humid climate. He came up with a guitar that was made of all graphite composite.
The early models designed in cooperation with luthier Lorenzo Pimentel.
By contructing the entire instruments top out of a consistantly uniform molded graphite, there is no need for bracing. This eliminates weight and deadened spots. The tone can be quite loud but balanced.
The neck is unique in that it is cast from a single graphite matrix instead of cut from a piece of wood. Due to this process, RainSong guitar necks have a consistant shape. The action can be set low without buzzing. The casting process also provides for consistant positioning of fretslots.
Though the necks have trussrods, they are used for customization of neck relief since the necks will not twist, bow or warp.
RainSong guitars come in only one color, black. The company states this is because they do not want to cover up the graphite. There are several layers of UV protected clear finish applied, buffed and sanded to a thin layer.
There are some other guitars that were made of carbon graphite or partially manufactured of this material, such as the original Steinberger bass and guitar made by designer Ned Steinberger that was made of graphite reinforced epoxy. Modulus basses have a graphite composite neck for added strength.
A company called Moses produces graphite retrofit necks for most style guitars including Steinberg.
Chrysalis Guitars manufacturers an inflatible travel guitar that is designed to be taken apart and placed in a small brief case.