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Has anyone tried to make a carbon fiber soundboard? I'm wondering if it can be done. A cursory search on making your own carbon fiber items shows it's mainly a matter of putting down sheets of carbon fiber material in a mold, applying a liquid resin, and letting everything cure. I'm envisioning taking a soundboard out of a grand piano, building a dam around its perimeter, and applying some sort of release compound to the board (you might even be able to do this with the soundboard still in the piano, thus creating a perfect fit mold). Then you just apply the carbon fiber concoction to the soundboard-shaped reservoir you've created, build it up to the thickness you want, and take it out of the mold. Then, sand and taper the board as you would a wooden board.

Does this seem even in the realm of possibility? I wonder if there is a certain way places like Hurstwood Farm formulate their carbon fiber that makes it different than your garden variety carbon fiber.

What do you guys think? Sound like an idea only a person who's never made a soundboard could dream up?

It would be very expensive carbon fiber sheets are not cheap

Carbon fiber is also proving not to be the best substitute anyways.
Seems there are other man made materials that show promise. I keep an eye on the luthiers and let them do the R&D for me. When I found a material of promise, i'll dive in.

The trick of course will be to match the stiffness of spruce, because too much stiffness might not be such a good thing either.

-chris

You might want to also look into laminated soundboards. Here's an article by Del Frandrich about all the benefits and misunderstandings surrounding laminated soundboards.

https://www.pianobuyer.com/article/the-benefits-of-laminated-soundboards/

I was going to mention Del. You beat me to it. 😁👍

Peter Grey Piano Doctor

It is in the realm of possibility. Somewhere in the YouTube universe I saw someone even using hide glue as the resin. You can make a board that is more stable with changes to RH and temperature, but the "tone" of the carbon fiber is much different from that of spruce. Piano makers of the past have indeed tried other tone woods for the soundboard. There were various degrees of success. For me, spruce has a good tone. I've looked into (and handled) guitar, other string instrument, and bow makers use of carbon fiber. It is all possible, but the tone isn't right in my opinion. It is not resonant. It is tight and focused, but not resonant. Maybe someone can find a work around, I don't know.

What's possible and what's desirable may be two different things.

I'm definitely open to experimentation. Myself, I built a synthetic soundboard about 45 years ago. It wasn't great -- but then, I didn't really know what I was doing.
I'm not sure that anyone fully understands soundboard function although there are many excellent craftsmen out there.

The CF soundboards I've seen "work" -- sorta -- but IMO really aren't ready for prime time.

The big problem is in doing something different -- and radically different, at that -- and expecting results to be the same. CF as currently used just doesn't sound the same as spruce.

One consideration: The carbon fiber that I'm familiar with requires a high temperature cure in an oxygen-free environment. You could probably get the latter with a large vacuum bag, but where to find an oven that big? Maybe I'm behind on this and there are options available to the general public that don't require autoclaves.

Carbon fiber is cool because it's strong and light, but it's also much stiffer than wood, though like wood its stiffness can be directional depending on the orientation of the fibers. So by playing with the orientation/weave and the thickness you could probably replicate some of the properties of quarter-sawn spruce. You'd probably also need to make a carbon fiber bridge and ribs for underneath, since gluing wood pieces to carbon fiber seems like you're just asking for trouble. And then while you're at it you might as well make the pin block out of carbon fiber, and then you'd have a piano that doesn't go out of tune when the weather changes.

Seems like a lot of work for dubious results. My .02

Peter Grey Piano Doctor

Carbon fiber soundboard is possible. However, classical guitars with carbon soundboard and balsa lattice bracing (Smallman, etc.), while being expensive and loud with long sustain, usually sound terrible IMHO - very thin and nasal with no color. Many classical guitarists cannot stand its sound.

Thin, nasal and no color is how i would describe the sound as well.

-chris

I was under the impression that carbon fiber soundboard makes good or better piano sound like in Phoenix Pianos.
But I never hear one in real life. only on youtube videos.

so this is not necessarily correct?

Go for it, I'd say. Maybe try a few small scale concoctions first to see what properties they have compared to a soundboard removed from a piano?

I have played pianos with carbon soundboards at Hurstwood.
Some of them (in particular a 5.5foot grand you would not believe was so small) sounded fantastic.
Some not great at all. Like wooden ones then really...good and bad

Interestingly, in order to sell them to pianists they had to put a veneer of wood on them!
Pianists wouldn't accept the carbon look...


Nick

Maybe the thing to do then, is to put un-veneered carbon fibre into upright pianos....

If you investigate what forms carbon fiber material comes in and all the varying molding processes that one may employ. You will find the options so diverse that it is dizzying.

Give me a few million dollars to hire the proper engineers and produce many test experiments and I think I could narrow it down. Should be some patents in there to boot.

Don't even think about playing around CF board design until and unless you REALLY understand the nuances of the molding processes and have lots of money to do lots of experiments, and oh, don't forget the benefit of finite element analysis.

I agree Roy. From what I have learned from my Boeing friends, figuring out how to tool a carbon fiber structure is far more important than most people would realize. It is more of an art than a science. The real tooling geniuses in composite design are in very high demand.

Indeed. Smallman guitars are quite bizarre to play. They are unbelievably loud - you can legitimately use them in a medium sized concert hall without needing amplification. But the tone is certainly not endearing. It's difficult to coax warmth and roundedness out of them. But hey, John Williams has played them for most of his career, so he must see some redeeming features in them - one can only assume he has adapted his playing style to get the most out of them.