Carbon Fibre instruments

[DanSwain]

Dear all,

Firstly, I apologise for being absent from this forum for such a long time! I need to catch up!

It's recently become known to me that there is a "friend-of-a-friend" resource that may be able to create vacuum-formed carbon fibre pieces for me.

My intent was to carve out an instrument in something like MDF, and then have them use that as a template to build the front and back pieces of the Guitars over that.

In peoples' experiences of Carbon Fibre instrument production here, what should I be aware of when I create the "template"?

I'd imagine that having an inverse mold would be easier for them, but I'm not sure how I'd be able to perform that myself, so would them effectively wrapping the MDF instrument template (one side at a time) be feasible?

Any thoughts or experience here would be appreciated! I've finished the 7-string fretless (kind of) I started 2 years ago, but this weekend I realised after a 4-hour rehearsal that it's pretty heavy, heavy enough to cause backache! This lead me to re-visiting this idea.

I intend on using the template twice, one for a fretted, and one for a fretless instrument. Thanks in advance for your help!

Kind Regards,

Dan

[elgecko]

There's some cool info here:

How I make a cf neck

[HaMMerHeD]

As far as I have been able to determine, carbon-fiber electric instruments are made around a solid core, not hollow. However, since the carbon contributes a great deal of structural rigidity and hardness, you can use relatively light and soft wood.

[elgecko]

Originally Posted by HaMMerHeD

As far as I have been able to determine, carbon-fiber electric instruments are made around a solid core, not hollow. However, since the carbon contributes a great deal of structural rigidity and hardness, you can use relatively light and soft wood.

These folks do monocoque (hollow) instruments.

http://www.emeraldguitars.com/

[HaMMerHeD]

I guess I should have said "mostly".

[Lazarus.Bird]

Oh man. Monocoque sounds like a great name for a terrible grindcore band.

[pilotjones]

BassLab instruments are also monocoque. I think they make form the carbon cloth around a foam base, and then dissolve it out afterwards.

[DanSwain]

Thanks for the input everyone!

Well it seems that the best method for me would be to make a core from foam for the sheets of carbon fibre to be applied to.

I don't particularly want any acoustic properties, more just a platform for the pickups and strings, with my own design around that. Would the best kind of foam to use be the pink style stuff that's used as external insulation for houses, between siding and the inner walls?

I think that my friends of friends use the vacuum bagging method, so I was unsure as to whether that kind of foam would withstand the pressure from the vacuum.

From what I've been told, the carbon fibre can also be used to screw into, providing that the holes are correctly piloted and tapped, like with wood, and that extra layers of material are added at those points. I could make recessed areas in carved core, so that when they're building the layers up the top-surface relief remains the same.

[MPU]

I'm just about to start a Parkerish carbon fiber/wood core composite fiver. I'm making the core out of obeche and maple and vacuum bag laminate a 1mm skin of cf over it. Pics will be here when this one starts.
Marko

[Keith Guitars]

Choice of core material depends considerably on just how light you think it needs to be. Foam can work, but there are varieties of wood that are extremely light and have more appealing qualities than foam as sonic and structural materials. Basswood, Paulownia, and even light poplars come to mind, as well as the obeche that MPU mentioned. Even balsa would work well if you can find pieces big enough.

The wood core would also have the benefit of being able to receive and retain screws without any extra difficulties.

If you're really committed to using a foam core, then I would suggest putting wooden blocks into the core to receive the screws for pickups, bridge, etc. Foam will work well to take up space between the load-bearing surfaces of the carbon, but it is quite compressible, and also has essentially no value for attaching critical hardware like a bridge. Drilling and tapping the carbon skin will not be of any use here, unless you're putting on a very thick layer, at which point it's not a skin at all!

Although carbon has some delightful properties that make it quite useful for many things, it's not always the right choice. A foam core/carbon skin body may be neat, and light, but I personally doubt that it will outperform a well-chosen wooden body in any meaningful way. I think the wood will sound better, be easier to work with, and will make for a structurally and and functionally superior body.

The only reason I could see for using carbon in a solid body would be if the body were extremely thin and/or heavily contoured, like (for example) the Parker Fly guitar. There, it makes sense, since the light, thin body needed some structural help. However, bear in mind that the primary role the carbon played for the Parker was to strengthen the back of the guitar - there was no carbon on the face - it just didn't need any.

MPU's threads have been great and well-documented - keep your eyes on what he's doing, and that should give you a good idea of how to go after this project.

Cheers!
Martin

[DanSwain]

Marko, I'm definitely looking forward to seeing your thread! I agree with Martin about your history of documentation - it's always inspiring stuff!

Martin, thanks for your in-depth answer, it's certainly given me some food for thought! I suppose that I'd taken the foam core under advisory from some people in the automotive world. It's cheap and easy to carve, and it would be fairly easy to remove sections for adding wood where screws would need to be added (e.g. bridge, pickup mounts, tuner mounts in the headstock...).

The light weight, for me, was more to make the instrument easier to balance, by adding the aforementioned sections of wood.

Having an all-carbon instrument was also a way of keeping me away from making mistakes with woods of a similar performance Carving the body on a cheap piece of foam and making a mistake isn't quite as tragic!

I'm not that bad really, but I can use it as an excuse for experimentation...

[elgecko]

Cool video on carbon fiber monoqoque instrument construction.

Carbon Fiber Cello