Here’s how I made the body for my carbon fiber acoustic guitar, part of a workshop at Techshop. It was made laying layers of carbon fiber and fiberglass over a cardboard mold, then hardening the fibers with marine grade epoxy. The mold was modeled after a 1940 Gibson L-00.
This is definitely an unconventional technique, but there are several examples of carbon fiber guitar makers — one company close to me is San Francisco-based Blackbird Guitars. They use carbon fiber to form the entire instrument; body, top, neck, fingerboard, etc. Mine definitely isn’t as polished and professional as theirs, but it was a great challenge that introduced me to a lot of new materials and methods. Considering this was my first time making an instrument of any kind, and my first time working with carbon fiber, I’m very happy with how everything turned out.
One note before I start, though — there is a lot of room for improvement in this process. The workshop was designed with complete beginners in mine, and therefore ignored advanced techniques such as vacuum bagging in favor of simple, intuitive methods. The whole body was laid up and finished with brush and gloved hands. For a very different approach using vacuum bags (which I hope to try in the future) see this Carbon Fiber Violin on instructables.com
I estimate it took me a bit over a week, working nights, to finish the body alone. Making and assembling the mold took one night, making the body took another 3–4 nights, and final shaping, finishing, and installing the other components took another 3–4 nights.
Here is my first attempt at a 3D ‘catch’ model of my guitar.
Why carbon fiber?
Carbon fiber isn’t going to replace wood body guitars anytime soon, but for those who want something different there are some definite advantages to using carbon fiber. As I understand them, the main reasons to use carbon fiber over wood construction (besides looks) are acoustics, durability, and ease of construction.
I don’t know a lot about the science behind guitar construction, but I’ll point you to Blackbird Guitars and Rainsong Guitars, two carbon fiber guitar makers that do a good job explaining the logic of using carbon. But my understanding is that properly constructed carbon fiber guitars have a very clear sound and loud volume. More importantly, once one finds a good design for a carbon fiber guitar, it’s much easier to repeat success than with a wood guitar. Every wooden component can vary slightly — grain direction, moisture content, knots or defects, etc. — and there is a lot less variation between sheets of carbon, so it’s easier to crank out duplicate models with reliable sound qualities.
In addition to the stability of the material, carbon fiber is just plain durable and strong. Carbon fiber (and other composites) is not affected by weather and humidity the same way that wood is. Improper storage of wood guitars can seriously damage the joints between components, whereas carbon fiber wouldn’t bat an eye traveling from the dry desert to the tropics in an instant. Carbon fiber is also strong. Before I installed the wood components, I could easily lean my whole body weight into the guitar shell. I didn’t test it, but I might have been able to stand on it without a crack.
Since my guitar is a mixed carbon fiber and wood construction, I don’t get all of these benefits, but it’s still darn strong. I don’t worry about hurting the body, and if any part of the guitar gets damaged down the road, it would be a lot simpler to patch it up or even rebuild the entire top than with a traditional wood guitar.
Ease of construction
The second half of this project, installing the wood components and strings, was exactly like making a traditional guitar. But compared to a traditional guitar, making the body was dead simple. I think the skills involved are more accessible for beginners compared to wood construction. In just one night I went from a bottle of epoxy and a pile of fabric to a nice guitar shaped body ready for finishing.
That same ease of construction made customization much easier. Instead of buying or making multiple special guitar jigs, clamps and tools, one need only change the mold to whatever shape is desired. I chose to make the standard design given to us by the instructors at TechShop, but others in the workshop chose to customize theirs a lot — from making cutouts and sound-ports in the side, to making a bass guitar.
That customization does come at a price, of course. While spruce and other standard guitar woods can be pretty cheap, carbon fiber is definitely not cheap. And while the laser-cut mold was cheap for me as a member of TechShop, I don’t know what the same service would cost from a third party. But these costs might be reduced with some creativity — making a non-laser cut mold out of foam should be possible, and perhaps other composites besides carbon fiber could work as well.