Carbon fiber bridge

[man dough nollij]

Has anyone ever tried to make a bridge out of carbon fiber composite? It seems like it would be stiff and light, and possibly transmit the vibrations to the top better than wood.

Since the stress on the bridge is all compression, would CF be good? It seems like most applications are for tensile strength, rather than compressive strenghth. Don't know. http://www.mandolincafe.net/iB_html/non-cgi/emoticons/rock.gif

[OzMando]

I think carbon fiber mandos often still have ebony bridges (I may be wrong) seems like that might be a good indicator to me.

[OzMando]

Would be interesting to hear carbon-fiber bridge on a wooden bodied mando though. #As far as the compression thing goes I don't have a scientifically based answer but the forks on my bicycle are CF and it seems like most of what they are doing is weight bearing/compressive work rather than holding a tensile force so maybe it is worth looking into. #Just a thought.

Besides CF usually looks pretty gnarly http://www.mandolincafe.net/iB_html/non-cgi/emoticons/tounge.gif

[Keith Newell]

I insert a carbon fiber rod in the center of all my bridges. I owned many mandolins over the years and the older bridges sagged and caused many problems so I decided to insert the carbon fiber to keep them straight.
Keith
http://www.newellmandolin.com

[OzMando]

Now we just need someone to design, manufacture, and sell some. I guess if the whole bridge is made out of CF it would be very difficult to fit properly to the shape of a top?

[evanreilly]

I have tried several experiments with CF saddles, mostly with laminate caps of other materials such as Fossil Ivory and bone.
I think it is the ideal material; light, inflexible and sonically transparent.
The down side of the material is it is not a user-friendly material to work with. Eats up even carbide drill and router bits.
And thanks to Mandolinkgn for making me a few CF pieces!

[Dave Cohen]

Before you get too excited, consider that the densities of cf/epoxy composite and cf/polyurethane composite are about twice that of ebony. In their favor, the elastic moduli ("Young's modulus") are much higher than ebony. That means though, that to keep the mass down, you would have to engineer a completely different design than the conventional Gibson-type bridges (either adjustable or the older non-adjustable type). That, coupled with the problem of avoiding the generation of airborne fibers when working the stuff, keeps my use of it to a minimum. After initial experiments, I have confined my use of it to neck reinforcement.

http://www.Cohenmando.com

[TomTyrrell]

CF b**jo bridges have been around for a while. Some like them and some don't.

[Steevarino]

Dave brought up a very good point. #Airborne particles of cf is the first issue that comes to mind for me, as a bridge maker, anyway. If I were to make cf bridges the way I now make them out of ebony and other woods, my work environment would be a bigger toxic mess than I would be interested in working in, even with dust collection, and other protective measures.

However, I do think the picture Evan showed, and what Keith described above #might be good compromises. #Maybe keep the bridge base and the top of the saddle wood, or whatever, and employ a small amount of cf along the bottom of the saddle, to keep it from sagging. #This way, you would be getting the benefits of carbon fiber (stiffness) with minimal health issues for the builder. #

Besides, I'm not so sure a bridge made entirely out of cf would help the mandolin to sound better anyway. #Keeping the bridge saddle from sagging seems to be the biggest benefit of using this material.

Steve Smith
http://wwww.CumberlandAcoustic.com
http://www.RedLineResophonics.com

[OzMando]

Isn't one of the points of carbon fiber that it doesn't have to be solid to have the same strength as other substances? I believe it can be sort of pushed into a mold as thin sheets and the layered up to the desired strength. I assumed we were talking about something hollow here, which, now that I think about it would be kinda weird in a bridge http://www.mandolincafe.net/iB_html/non-cgi/emoticons/biggrin.gif

Maybe you can never have too many resonating chambers of air ? http://www.mandolincafe.net/iB_html/non-cgi/emoticons/rock.gif http://www.mandolincafe.net/iB_html/non-cgi/emoticons/tounge.gif

[Joe F]

A few years ago, a local luthier made a graphite (CF) bridge saddle for my Kentucky KM-200S. #With mahogany sides and back, it has always been a fairly quiet instrument, but the increase in volume and clarity with the CF bridge was striking. #People in the jam circle reported that they could hear me clearly for the first time (not necessarily a good thing!) after the conversion.