Instructables
In this instructable I will show you 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 SF 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. I'd like to share the new skills I learned along the way with anyone who's interested. 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 probably 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 other instructable - A Carbon Fiber Violin.

It's really hard for me to estimate the time and money that went into making this, because I was working on so many project at once I wasn't keeping track very well, but I estimate it took me a bit over 1 week, working nights ,to finish the body alone. I'll break down costs later when I list the materials.

I worked on the entire guitar project most nights for several weeks - making and assembling the mold was done in one night. Making the body took another 3-4 nights - it probably could be done in 1-2 nights, but I had trouble with one coat of my epoxy drying - explained later. After taking a break to work on the other guitar components, 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. Click the 3D view button on the left to activate the viewer.

 
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DanW1311 months ago
Not familiar with the 123Make software, but if there's a tool or way to slice the guitar vertically vs. Horizontally you might have a better resolution as far as your mold goes…Also by using slices tht equal the thickness of Cardboard you used i.e 1/8", 5/32nd" ect then simply Glue & stack them in order and fill in the void w/Bondo to make your mold.
workislove (author)  DanW1311 months ago
Yeah, you can slice it up any way you want. I hadn't thought about playing around with the orientation like that, but perhaps I'll try and see if it makes a difference next time I try to make a mold.
DanW1311 months ago
Another note for you to keep in mind is I see you used Elmers type Glue on CardBoard which probably caused the paper on CardBoard to expand due to the water content in the Glue, It might be better to use a contact cement though alittle more costly but IMO would have been better to keep the cardBoard from expanding from Water Content.
workislove (author)  DanW1311 months ago
It did expand a bit - and on top of that I did nothing to clamp it down. In this case, I wasn't too concerned about the exact final dimensions - I made the body first and everything else was designed around it. I mostly do simple woodwork, so glue is my go-to solution. But that's a good tip for future projects, I'll keep it in mind.
DanW1311 months ago
Don't wanna sound like I'm picking your work apart here but I hope you take in a Constructive manner. Instead of using CardBoard wouldn't it not have been better to use say Balsa wood for the rib construction vs. CardBoard material just form the standpoint of strength ?
workislove (author)  DanW1311 months ago
No worries, I love criticism of this type.

I used balsa because this was part of a prepared workshop, and they were using cardboard, so I just followed along - if I do this again I'll do my own research and definitely alter some of the methods - for instance I'm very interested in vacuum forming the CF instead of just laying it up.

That said, I'm curious what advantage balsa would provide in this application over the cardboard? It seems it served its purpose by providing the shape for the mold - unless one is making a reusable mold it doesn't need to be that strong, from my understanding.
DanW1311 months ago
Actually not too bad for your 1st attempt, I bet after you sleep on all the steps involved you could refine yoru work and make a guitar just as good as some of those "Pro's" Look's Good !!
workislove (author)  DanW1311 months ago
Thanks. I mostly do woodwork, and this was my first time trying composites. I'll definitely be returning to this type of thing in the future, maybe even another instrument - but taking it slow for now
vnams1 year ago
What kind of carbon fiber cloth did you use? You mentioned that you used some inexpensive cloth - would you advise someone to use a different kind?
workislove (author)  vnams1 year ago
This is the specific carbon fiber I used, straight weave. It worked fine, but it was a bit hard going around tight corners. This twill-weave carbon fiber is supposed to be better than straight weave for wrapping 3D objects, but I can't say anything from personal experience.

This is the other material I used, called S-glass. It's a type of fiberglass. The only reason I used it was to add bulk and stiffness to the shell inexpensively. Fiberglass is pretty strong, but not as strong as carbon fiber, and it also looks strange with epoxy - the moment it soaks up the epoxy it becomes translucent, and you can't see the pattern anymore.

I did this as part of a workshop, and it was my introduction to composite materials - so I can't say a lot about the different options.
thassaj1 year ago
Impressive! Would be nice to hear a few chords played on it so we can hear how it resonates.
Alienjones1 year ago
I've had some experience in building lightweight boats using carbon fiber (CF) and I notice some flaws in your construction that will almost certainly result in less than perfect harmony in the tone. It is almost essential to cure CF in a vacuum. Imagine a plastic bag 23 feet long with a sailing boat hull in it having a vacuum pump draw all the air out and You'll get an idea of what I've worked on. You can buy vacuum bags at hardware and department stores. They use them for compacting clothing into small bundles for storage, evacuating the air with a domestic vacuum cleaner.

Think now about assembling your guitar over a concrete form. Yes, concrete! and putting the whole lot into a plastic bag after you've saturated it with resin. Use a vacuum cleaner to evacuate the air and the flaws I see in this example will not be there. If you can't find a ready made bag large enough for your guitar, try making one using sheet plastic and swimming pool liner repair glue with the valve from a cheap storage bag.

I applaude your enthusiasm in experimenting and hope you continue to develop a technique that will suit this product. I think myself that harmony in a box depends 60% on the shape, 20% on the material used for construction and the remainder split up between how you hold it and the design of those pieces of material that support the strings. I think this shape is most likely to work but if the CF has pockets in it that prevent continuous sound reflection at the same energy, the overall tone of the instrument will suffer. Excellent try. I'll be very impressed if you keep developing your molding techniques and actually produce an excellent guitar.
gn0stik1 year ago
No pic of the completed guitar? Oh, come on!
workislove (author)  gn0stik1 year ago
Haha, i did all the parts as separate instructables. Didnt think to add finished pics here. But thats a good idea, ill add them later.
agis681 year ago
looks like a good job...waiting to hear it also.
dawg0651 year ago
just wonder how does it sound?
alphydan1 year ago
Beautiful work! Congratulations
Samw1 year ago
This is fantastic. Better than an Ovation to me. How does it sit against your body? I always found Ovations sat oddly or rolled away from me when I didn't want them too.
pooter14331 year ago
Very cool. Carbon fiber and traditional fiberglass can be a messy frustrating experience. Good on you for giving it a go on a complex build like a guitar.
orator1 year ago
I was unaware that Gibson ever made a round back guitar. The diagrams don't show it, either.
workislove (author)  orator1 year ago
Sorry if it wasn't clear - first the dimensions were taken from the plans, then later the computer model sides were rounded over. This is because the type of fiber being used doesn't tolerate sharp corners.

I could have made the back and sides as two pieces, but since I was doing this as part of a group build workshop I didn't want to go too far in my own direction - I'll leave that for my next project.
freeza361 year ago
Looks like an Ovation
danny61141 year ago
Is this a heavy guitar compared to the wood original?
workislove (author)  danny61141 year ago
Good question, I haven't compared them side by side, but I'm not sure - but I think they are probably comparable. In general I think carbon fiber guitars are lighter, but the method I used requires more carbon and more epoxy to set strong, so it balances out. A properly vacuum formed one is probably lighter.
Re-design1 year ago
Very, very nice!
workislove (author)  Re-design1 year ago
Thank you!
crispycat1 year ago
RESPIRATOR!!!
carbon filings will give you just as nasty Permanent lung infections as fiber glass will!! 
even small particles from a hand file or saw can lead to alot of pain! 
of course dremel and other powertool cutting of carbon and fiber are far more dangerous
but if you dont want to be on a ventilator in later life wear a proper mask whenever using tools on composite materials
and no a paper one will not do!! 

other than that its an awesome project! 
personal id of made a mould of the guitar body and vacuum infused the resin for a cleaner stronger finish! but thats alot more work!
i seriously love the inlay work wow that is something i need to practice

finally .. how does it sound? alot of people say that carbon has unique acoustic propertys!?
workislove (author)  crispycat1 year ago
You're right, I wrote respirator once, but it bears repeating. The first time I cut it I just had a paper mask, and quickly stopped and ran for my respirator. The guy pictured cutting it is an experienced shop guy who just doesn't always take those precautions - but maybe I'll add a safety warning there.

I love the idea of vacuum infusion, but felt it was too much to take on for my first project. I'm looking into it for the future, though.

I'll let you know how it sounds soon. My first tests were promising, but I got too excited and did a poor job mounting the bridge and it started to separate, today or tomorrow I'm going to do a proper job of clamping it down.
tridrles1 year ago
Great job!
I started making carbon fiber ukuleles about four years ago...it's a hobby. Mine look very similar to your design with rounded body /bottom/back with concave neck back so my thumb stays back.
I've completed 7. I vac bag them in a female mold so the outside looks almost perfect when it comes out.
I'm now working on steam pressed arch top for them.
Uke 8 005.jpg300deg R.JPG
workislove (author)  tridrles1 year ago
Very cool! Looks beautiful. I was actually thinking about a ukulele - I have a bunch of smaller carbon pieces from my own project and abandoned by others at the end of the build. Maybe I'll try your method.
Do you make them for sale
Nabil tridrles1 year ago
Now that's the approach! A female mold is the way to go!
yeah, I concur with tridrles, using a vac bag is essential for a strong finished result. stops redues the formation voids, bumps and the like. cool job over all wood work makes a nice contrast to the fiber

Why didn't do a carbon top and neck ?
workislove (author)  jackthursby1 year ago
This was my first time ever working with carbon fiber, and it was part of a workshop that only covered this method. I'd like to try this again in the future, and if I do then I will definitely look into vacuum bagging.

Two people in the group went for the full carbon instrument. I haven't seen either completed yet, but one of them seemed promising.
ku5e1 year ago
You could also use my old method for making fiberglass and carbon fiber OOAK RC airplane fuselages. Sculpt the form in Styrofoam then completely cover in the glass mat or carbon mat. I use epoxy resin (reason will be clear by the next sentence) to impregnate the mat. Then when the resin is dry and set, I drill a hole where needed, then I pour a solvent that will melt the Styrofoam (gasoline works fine, but I use Acetone in a well ventilated area) and not the epoxy.
workislove (author)  ku5e1 year ago
Interesting. I imagine that generates quite a lot of fumes. That won't do for my current workspace, but I like the idea.