Official Luthiers Forum!

In seeing a few posts about using carbon fiber, I was wondering does it machine and glue like wood?

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Bryan Lafleur
www.lansegriseaccordions.com

No.

Definite no!

No...for the very reason that CF is useful, namely, its stiffness, it id also quite abrasive to tooling. Your basic sharpened steel cutting tools will dull much faster cutting CF than wood.

Use carbide tooling if possible...and be prepared that even carbide will dull quicker cutting CF....but carbide will last much longer than steel.

But don't be afraid of it either. If you are good at sharpening then it will carve when you put a chisel to it. It will sand with the same paper you use for wood.

I would suggest sanding CF well with 240...and use epoxy to glue it to wood.

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I read Emerson on the can. A foolish consistency is the hobgoblin of little minds...true...but a consistent reading of Emerson has its uses nevertheless.

StuMusic

Interesting thread. I have wondered whether braces like Mario's, with CF sandwiched vertically between spruce, could be carved in the same way, using the same tools, as spruce-only braces. It sounds like the answer is yes, but one should plan on sharpening their tools more frequently?

Mario, if you don't mind me asking, do you tap your tops and adjust the height of your x-braces as you fine tune them, or do you set your x-braces to a predetermined height and profile and then just adjust the other braces (tone bars, finger braces) to "tune" your tops? Thanks!

Good info Stuart. I just got a stack of CF and was wondering how to handle the pre-fab. Now I have a pretty good idea thanks to you.

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Joe Beaver
Maker of Sawdust

You need full body protection to sand CF... its way worse than fiberglass (and that's pretty bad when you sand it, it causes itching anywhere it touches your skin). If you want to cut CF I suggest using a wet diamond bandsaw, that tool would also be useful for cutting shell inlays too.

Only thing that will stick to carbon fiber is epoxy, and the carbon prepreg needs to be sanded first.

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Cat-gut strings are made from kitten guts, stretched out to near breaking point and then hardened with grue saliva. As a result these give a feeling of Pain and anguish whenever played, and often end up playing themselves backwards as part of satanic rituals.

Typhoon Guitars
http://www.typhoon-guitars.com

I'm not Mario, but (thanks to his inspiration) I have done a few braces with laminated CF. To expand on my somewhat succinct answer:

- CF can be worked with most woodworking tools, but it will dull the hell out of them
- Abrasive planing (read: power sanders) make short work of shaping braces. I did mine on a belt/disk combo and spindle sander. Wear long sleeves and use dust control, because like Tai says, itch ahoy otherwise. Plus good respiratory protection, but that should go without saying even when sanding wood.
- You can adjust using chisels, but you will more or less ruin the edge. Fixable, but you will likely need to do more than just hone to get it back to scratch. I have one decent chisel dedicated to this purpose that I don't mind regrinding from time to time.
- I tend to glue with Epoxy, although I've successfully used polyurethane and CA as well.

I laminated some carbon fibre cloth between two pieces of Brazilian rosewood veneer to make a back and side set . Every time I ran the plates over my jointer the CF made a small nick in the knives.

I think you're confused. carbon prepreg is a a weave that's impregnated with un-cured resin. The weave (or tow or whatever) is put into use and then autoclaved to cure it.

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http://www.birkonium.com CNC Products for Luthiers
http://banduramaker.blogspot.com

It's carbon, folks.
They make diamonds out of it, ya know.

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"Act your age, not your shoe size" - Prince

They also make pencil leads out of carbon, all depends on the way the carbon atoms are bonded to each other.
CF isn't nearly as soft as graphite and isn't nearly as hard as diamond.

Ice is made out of water, too.

If your very proficient at sharpening and have nothing better to do........ well try to carve carbon fiber with a chisel. As stated the dust/fibers are nasty.

Yes, I "tune" and adjust each one individually. I pre-shape the braces with the bandsaw(and a dull blade...) and belt sander, then work the braces after the top is completely braced with a combination of small planes, chisel, and some sandpaper. Kills the edges to where they need a touchup after I'm done, but that's likely why I've become really good at sharpening stuff...

Epoxy is NOT the only thing that sticks to it. I've used polyurethane glues exclusively since the late 90's, and I've even tested HHG for the brace laminations, and it held really well.

It must depend on the CF. When I tested HHG it popped off instantly. I can't remember where I got it though.

I just bought about 200' of CF tow and it was described as seized for easier handling and easier layup.

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http://www.birkonium.com CNC Products for Luthiers
http://banduramaker.blogspot.com

Just curious but does carbon fiber have a higher stiffness to weight ratio than a piece of quater sawn spruce of the same dimension? I

Richard

Higher stiffness to weight ratio, as well as higher density... which means that a piece of the same dimensions will be little bit heavier than spruce, and a whole lot stiffer.

That's why they're used in the aerospace industry, not to mention carbon fiber doesn't have the huge variation in stiffness and density like wood does.

I am curious what do you guys think of Carbon Fiber guitars? Seems like once they got everything just right they don't even need to bother voicing the guitar at all, since it will be fairly consistent from instrument to instrument. Does that mean that if one day carbon fiber guitars become the norm (due to wood becoming rarer) luthiery as we know it will end...?

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Cat-gut strings are made from kitten guts, stretched out to near breaking point and then hardened with grue saliva. As a result these give a feeling of Pain and anguish whenever played, and often end up playing themselves backwards as part of satanic rituals.

Typhoon Guitars
http://www.typhoon-guitars.com

Unless there is a drastic price reduction, carbon fiber guitars won't be the norm for a long, long time.

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"Act your age, not your shoe size" - Prince

Thing about composite is, that the cost of material isn't really that high, but its the cost of working with the material. Carbon fiber is difficult to work with without jigs and vacuum fixture but if a company (like Ovation) decides to mass produce carbon fiber guitars, then their price is going to be very very low while providing very good sound.

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Cat-gut strings are made from kitten guts, stretched out to near breaking point and then hardened with grue saliva. As a result these give a feeling of Pain and anguish whenever played, and often end up playing themselves backwards as part of satanic rituals.

Typhoon Guitars
http://www.typhoon-guitars.com

I have used CA to stick CF to ebony successfully. I tried it as an experiment once - I bound the edges of a fretboard with thin CF sheet from an aircraft model shop. CA stuck it instantly and there haven't been any separation issues since.

Cheers,
Dave F.

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Cambrian Guitars

"There goes Mister Tic-Tac out the back with some bric-brac from the knick-knack rack"

Define "very good sound".

FWIW: I've found epoxy, CA and polyurethane glues to stick really well to CF. Titebond not so much, fish glue and hot hide glue a little better

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Rian Gitar og Mandolin

I think that is a very subjective thing. For example some people loves the sound of a Stella even though most others would probably not spend a lot of good money restoring them, while others are perfectly happy with the sound of a $50 dollar guitar. Some thinks very good sound means loudness or bass.

Thing is, whats stopping companies like Ovation (I can see them doing this) from producing inexpensive Carbon Fiber guitars that will have consistent sound from one instrument to the next? Wood can't be engineered to have consistent quality but Carbon Fiber can. Engineering is expensive but when mass produced the final price of the product can be brought down. Plus with things like Lacey act, rarity of quality woods, some might think producing carbon fiber guitars are worth it.

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Cat-gut strings are made from kitten guts, stretched out to near breaking point and then hardened with grue saliva. As a result these give a feeling of Pain and anguish whenever played, and often end up playing themselves backwards as part of satanic rituals.

Typhoon Guitars
http://www.typhoon-guitars.com

The same can be said of wood guitars. Right?
That's why we charge so much to make them.



First - I HATE the way Ovations sound, especially the carbon fiber Adamas stuff.

Second - what a boring old world it would be if all guitars sounded as sterile as an Adamas.

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"Act your age, not your shoe size" - Prince