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Nov 22, 2020 - 9:59:51 AM
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13341 posts since 6/29/2005

I know that carbon fiber is constantly discussed on this forum—loved by some, hated by others.  I set out to make a tone ring that isn't a copy of a Gibson flathead, made in another material.  This one is pared down in a kind of cove profile.


I make a number of different tone rings, each of which has a particular sound quality.
Lately, my SuperWoodie tone ring has become very popular, more so than the brass and bronze ones.

The SuperWoodies are lighter than brass / bronze ones (as you can imagine), and while they sound remarkably similar to the metal ones, they have less overtones and a lot of clawhammer / old time people like them.

At any rate, I was working on a bronze foundry tone ring project and just came to the conclusion that the world doesn’t need yet another 3 pound bronze banjo tone ring exactly like a Gibson one.  I had already made foundry patterns, and decided I would use that work I had in hand towards developing a carbon fiber one, which I have been interested in—just to see if it would actually work.

My first prototype, based on my bronze design, is 13/16” wide, designed to overhang the rim, and has a 6061 aluminum skirt.  It weighs 11 oz, which is less than a quarter the weight of a bronze one, and half the weight of a SuperWoodie

One version of it looks like a black snake coiled up, and I was toying with the idea of calling it “Ouroboros” or maybe “Carbon County”, a rugged county in PA, once a coal mining center somewhat near where I live.

I installed this prototype on a banjo I had in-house that has a removable resonator, so I could try it with and without

Here you see the overhang inside the rim—this is a laminated rim, about 5/8“ and a cherry neck.

I think it’s remarkable sounding—my wife says "bell-like", and it reinforces my nagging fear that I don't fully understand the way tone rings work, and find it curious that a tone ring made from wood, cast metal, fabricated metal and something like a carbon fiber matrix can all sound so similar, in light of discussions about miniscule fractions of metal differences in this alloy and that one, and various woods used in woodies.

As a follow-up, I made a second prototype, this one 1 1/8” wide, 13 oz,. and following the profile of my SuperWoodie.  This one looks like the coiled snake, and I don't know what the carbon fiber material I got to make it is used for, but I had to declare what I was going to use it for, and provide my name
It

It's pretty cool-looking, at any rate.  You have to let these "mature" for a while because the epoxy resin in the matrix takes a while to fully cure and reach its maximum hardness—maybe I should name it "the Matrix".
I don’t detect any radical difference between the two designs that would justify the extra weight, although the wider one may be slightly “plunkier” (something to learn there), so may be preferred by old-time players in exchange for 2 oz.  a slightly different sound.

I am going to offer these to my customers who’s banjos are currently in process, and no doubt develop a 12” model.  I think it would be unfair for me to ship a new banjo to someone who has been waiting not so patiently for a long time, then announce that I had developed a new innovation they may have wanted if they had known about it.
I already have three bluegrass banjo customers who want to switch over.  These are interchangeable with other tone rings I make.
It cuts well over 2 pounds off the weight of the banjo, which is meaningful.  I'm going to make one and put it on my pre-war Granada to see what happens.

I can say that my prototype is a joy to play and I can feel the lack of the two pounds.

I am posting a video that has sound samples with and without the resonator, in G, A, and double C to put it through the paces.

Here’s a direct link to the youtube, which would play it full size
https://www.youtube.com/watch?v=3WknZ5KcId4&feature=youtu.be


Edited by - Ken LeVan on 11/22/2020 10:18:10

Nov 22, 2020 - 10:08:54 AM
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1052 posts since 1/9/2012

It sounds... it sounds just like... it sounds just like a banjo! wink

Always interesting, always beautiful.  Bravo.

(But it turns out really hard not to sound like one if it's well made.)

Nov 22, 2020 - 10:25:17 AM
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13341 posts since 6/29/2005

quote:
Originally posted by davidppp

It sounds... it sounds just like... it sounds just like a banjo! wink

Always interesting, always beautiful.  Bravo.

(But it turns out really hard not to sound like one if it's well made.)


Thank you David!!

I'll admit I was thinking about you every step of the way with this, imagining I was following and implementing some of your ideas.

And yes, it would be very hard to make it not sound like a banjo!

Nov 22, 2020 - 10:26:13 AM

2274 posts since 9/25/2006

Sounds awesome. This is going to be a very popular product. I reviewed a carbon fiber ring for BHO years ago and loved it.

Nov 22, 2020 - 10:26:42 AM

2274 posts since 9/25/2006

...and I gotta get me a longneck with one of these babies!

Nov 22, 2020 - 10:32:08 AM
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932 posts since 10/31/2007

I have a five string with a CF tone ring. It was made by a composites guy from the UK. He bonded it to a maple rim. I also bought his form and templates thinking I would some day become a CF tone ring maker.
At this point it is not going to happen.
That being said, my friend Dick Guggenheim felt this was one of the best three five strings he has ever heard.

This is a beauty, Ken! And the sound is what I would hope to hear from CF.

Nov 22, 2020 - 11:19:31 AM
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1208 posts since 5/19/2018

Your work always amazes me. Mad scientist, alchemist and artist....

Nov 22, 2020 - 12:10:50 PM

7880 posts since 1/7/2005

They sound great, Ken. How does the weight compare to your woodies? What kind of sound does the carbon ring have if you suspend it and tap on it? Does it ring like a bell, or is it acoustically neutral?
Do you construct it in a mold? I suppose one could mould a tone ring plus rim in one piece.

I love your experimental nature. Always up to something new and unique.

DD

Nov 22, 2020 - 12:45:18 PM

4555 posts since 9/7/2009

Sounds great Ken! I heard your best friend singing along, too! :) 

Nov 22, 2020 - 12:53:39 PM

13341 posts since 6/29/2005

quote:
Originally posted by Dan Drabek

They sound great, Ken. How does the weight compare to your woodies? What kind of sound does the carbon ring have if you suspend it and tap on it? Does it ring like a bell, or is it acoustically neutral?
Do you construct it in a mold? I suppose one could mould a tone ring plus rim in one piece.

I love your experimental nature. Always up to something new and unique.

DD


Dan,

 

at 11-13 oz, It weighs half as much as a typical SuperWoodie.

When you hang it, it just goes clunk—no ringing sound at all, although the epoxy in the matrix takes several days to fully cure to specified physical properties, and I didn't wait very long, so it's still curing.  I would call it acoustically neutral, so it's not any ringing tone that makes it work, but the woodies don't ring very much either.

I made it in an RTV mold, which was the mold I used to make the waxes for the ill-fated bronze foundry project—one door closes and another one opens.

I tried a couple of different methods of making the matrix, one with continuously woven tube, which looks like a snake, and one with random fibers. They both work, the random fiber method is messier, but you can get more fiber into the matrix that way.

There are ways you could produce a rim, probably as a lamination, as in a surfboard or something like that. The simplest method would probably be to use prepreg as the outer and inner layers in some kind of a mold. It would be a mess, and you'd have to have it come out to exactly the desired dimensions because you couldn't machine it down.  It would be something suited to mass production.

Pure casting is problematic because the resin with the fiber is impossible to work with—it's a hairy mess that sticks to everyting and is very thick—even if you jammed it down into a mold there would still be big gaps.  I am using that kind of system to make body-neck interfaces for banjo lutes, and have done it for 6-string banjos with fingerboards that go over the pot.  With a flat mold, you can only get one side of it to be good, and the other side is a mess that has to be sanded down.  It's interesting stuff for sure.

When I post a thread about Andy Fults's banjo lute, I'll show that—banjo lutes need an interface between the body and the neck because of the pear- shape of the body where it joins the neck

I could make resonators that would be very light and strong, and that might be a good use, but you could also use Tyvek or fiberglass for that, because resonators aren't under any physical stress—of course, they wouldn't look so hot compared to wood, and probably have no great demand—you'd have to have a reason, like a parabolic shape or something that was efficient at deflecting sound.

Ken

Nov 22, 2020 - 1:17:14 PM
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13341 posts since 6/29/2005

quote:
Originally posted by BNJOMAKR

Sounds great Ken! I heard your best friend singing along, too! :) 


Thanks, Marvin,

Hugo loves to sing, and won't stop for around 10 minutes, even if I am just trying to tune a banjo—he seems to like the higher register in the key of A.

He is now training our younger dog, a doodle, to sing, although I don't think she really understands what's going on—just chimes in.

Hugo also doas classical, as evidenced in this video, where he sings along with Bach with my wife, my niece and her husband.

https://www.youtube.com/watch?v=6p5N254_I-s

Nov 22, 2020 - 1:24:27 PM

7880 posts since 1/7/2005

Kevlar might also be something to consider. It's used with epoxy resin on canoes and kayaks to get the strongest, lightest construction for the hulls. And canoes do take a beating. For boats, carbon fiber seems to have limited use. Not quite as strong as kevlar, but is extremely slippery. They sometimes add a layer of carbon fiber to the bottom of the hulls to reduce abrasion. The carbon just slides over rocks. Probably not a major worry for a stringed instrument.
Any way, it will be interesting to see where your experiments take you. From the recording, it sounds like you're heading in the right direction.

DD

Nov 22, 2020 - 1:46:04 PM

13341 posts since 6/29/2005

Here's a great video, which I have watched several times.

https://www.youtube.com/watch?v=KHXVf0SaJpA

I used carbon fiber because of the superior stiffness / tensile strength characteristics, but with a resonatorm Kevlar would probably work great.  I am seriously considering the wood / Nomex® honeycomb / wood laminations used by some guitar builders for sounding boards.  Might be great for a resonator—I have some of the Nomex, but haven't been able to use it as yet—so many things and so little time.

Nov 22, 2020 - 11:42:36 PM

64 posts since 5/31/2009

"Kevlar might also be something to consider. It's used with epoxy resin on canoes and kayaks to get the strongest, lightest construction for the hulls"

As Ken alluded to, Kevlar has less rigidity/stiffness than CF.

I'd be interested in a tone comparison between CF and basalt fiber.

Nov 23, 2020 - 4:29:41 AM

13341 posts since 6/29/2005

quote:
Originally posted by awildman

"Kevlar might also be something to consider. It's used with epoxy resin on canoes and kayaks to get the strongest, lightest construction for the hulls"

As Ken alluded to, Kevlar has less rigidity/stiffness than CF.

I'd be interested in a tone comparison between CF and basalt fiber.


Based on the little bit I know about those materials, any of them would work, and you could alter the geometry of the tone ring to suit whatever the relative strengths and weaknesses of the material was—you would  just have to do some experimentation.  As I noted earlier, these things do not "ring" like a bell, so a ringing quality is not of any consequence—brass /bronze tone rings, once in contact with the rim don't ring, either—ditto wood.

Nov 23, 2020 - 6:18:09 AM

184 posts since 4/3/2009

quote:


Originally posted by Ken LeVan

... and just came to the conclusion that the world doesn’t need yet another 3 pound bronze banjo tone ring exactly like a Gibson one....

... it reinforces my nagging fear that I don't fully understand the way tone rings work, and find it curious that a tone ring made from wood, cast metal, fabricated metal and something like a carbon fiber matrix can all sound so similar, in light of discussions about miniscule fractions of metal differences in this alloy and that one, and various woods used in woodies....

Ken, I continue to be amazed by your craftsmanship, creativity, curiosity and (lack of) conformity.  I respect the opinion of someone who knows what they don't know.  Thanks for your always "must read" posts, and for providing evidence fro all to see and hear.

Nov 23, 2020 - 6:23:18 AM

184 posts since 4/3/2009

Also, this OT, but are you using Corian for binding? I like the speckled look.

Nov 29, 2020 - 3:30:50 AM

Dragonslayer

Mozambique

272 posts since 10/9/2019

Cool! I've been playing a carbon guitar for years.
It sounds good, and the weight savings are for sure helpful.

Nov 29, 2020 - 5:42:51 AM

13341 posts since 6/29/2005

quote:
Originally posted by banjodobro56

Also, this OT, but are you using Corian for binding? I like the speckled look.


I do use Corian for different kinds of bindings.  It comes in a lot of colors and speckles.  I get scraps from kitchen cabinet contractor.

Nov 29, 2020 - 8:46:13 AM
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3927 posts since 5/12/2010

It sounds great, and I am all for building lighter instruments which becomes increasingly desirable for aging banjo players.

I am always impressed with your creative imagination, skills, and willingness to experiment. There is a true blending of science and art in your work.

I am also sitting on the edge of my seat after reading:

"When I post a thread about Andy Fults's banjo lute, I'll show that—banjo lutes need an interface between the body and the neck because of the pear- shape of the body where it joins the neck"

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