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Thread: carbon fiber instead of truss rod

  1. #1

    Default carbon fiber instead of truss rod

    I am a player looking at the purchase of a mandolin made with a carbon fiber insert instead of a truss rod. I'm sure I would wish I could make adjustments to the neck if time were to alter the shape of the neck.
    Is there something about this approach that obviates the need to someday make adjustments?

    Thanks!
    Papawhisky

  2. #2
    Moderator MikeEdgerton's Avatar
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    Default Re: carbon fiber instead of truss rod

    While you're waiting for an answer take a look through these threads. The applicable topics will be apparent.
    "It's comparable to playing a cheese slicer."
    --M. Stillion

    "Bargain instruments are no bargains if you can't play them"
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  3. #3

    Default Re: carbon fiber instead of truss rod

    "Is there something about this approach that obviates the need to someday make adjustments?"

    The short answer is yes. The fiber rod is so stiff the neck should never require adjustment. Nothing lasts forever of course. But even a neck with an adjustable truss rod may someday need to be reset or replaned, they don't "adjust" all that far. It's really a question of what makes you comfortable. I personally have never felt the need to adjust a truss rod on any instrument I've ever owned, so I wouldn't miss that feature. YMMV

  4. #4

    Default Re: carbon fiber instead of truss rod

    Thanks for the threads. I actually did a search before I posted but didn't come up with the truss rod vs CF thread.
    Thanks again, I learned what I needed to know.

    Papawhisky

  5. #5
    Violins and Mandolins Stephanie Reiser's Avatar
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    Default Re: carbon fiber instead of truss rod

    I am almost ready to stain my first CF stiffened mando, and maybe I can give a report in a year or two. I have never had to adjust a trussrod, either. I finished an F-4-type with no trussrod or stiffener at all and the neck is performing nicely. Seems to me that the trench for the TR just weakens the neck, but I am no professional. Most mandos, though, have adjustable TRs. If you are wondering whether or not to order one or buy one with CF for a stiffener, I would not hesitate. I know of at least one full-time professional on this board who uses CF exclusively. In a couple of weeks I will be starting a 12-string guitar with a double CF stiffener laminated neck.
    http://www.stephaniereiser.com then click mandolins

  6. #6
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    Default Re: carbon fiber instead of truss rod

    I have adjusted trussrods in the past on some of the mandolins I have owned. I was really glad I was able to tweek the neck just a tiny bit to take a little dip out. Plays like glass. The thing that sells me on the adjustable truss rod is that most all the great builders out there use this feature. That just tells me a ton right there. When I was a pup Martin guitars did not have an adjustable rod. We all know how hard they were to play. It was a joke when I was a kid that Martin's played great on the first 5 frets! Even the salesmen at the top L.A. guitars shops would tell you that! They all have the adjustable neck now! Nick
    ntriesch

  7. #7
    Registered User Rolfe's Avatar
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    Default Re: carbon fiber instead of truss rod

    There is no comparison between a guitar neck and a mandolin neck. Out of over 300 mandolins built with a CF bar only three have come back to be releveled and refretted; that's 1%, and it was done at no cost to the owner. There were far more problems with truss rods in the Unicorn mandolins. After seeing how well CF worked in the Phoenix mandolins, Rigel adopted them.
    Rolfe Gerhardt

  8. #8
    kestrel
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    Default Re: carbon fiber instead of truss rod

    "Seems to me that the trench for the TR just weakens the neck..."

    Amen.

    Cut away a enough wood from a mandolin size neck, and you're definitely introducing the need for something to take out the bends from the now weakened wood. What's the truss rod going to do for a wind or side bend? A properly sized and installed CF bar will resist stresses in all directions. I can see the desirability of a truss rod in longer necked instruments, but even then, it would seem that CF used used along with the TR would be beneficial in counteracting the other directional forces.

    Gene

  9. #9

    Default Re: carbon fiber instead of truss rod

    I don't know about that. If you cut out the trench, and then back-fill it with a steel rod, and maybe a wood filler strip on top of that, I don't think it is weakening the neck. The weak area, to me, seems that it might be the area you have to clear out around the truss rod neck (on the peghead area) so you can get a wrench around the adjusting nut.

    Another issue with this is what the customer thinks. I get asked quite often if my mandolins have a truss rod in them. I think that, esp. with such a short neck, one is not really needed. However, if I were to go "truss-rodless" I feel that it would bring up all kinds of concerns with some potential customers. Now, there's a poser, eh...?

  10. #10
    Registered User amowry's Avatar
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    Default Re: carbon fiber instead of truss rod

    So far my experience has been the same as Rolfe's-- With the 30 or so mandos I've built with CF, the necks have been consistently better than my previous ones with trussrods. By "better" I mean that the relief is always where I want it, the necks are noticably stiffer, and they've shown no signs of changing over time.

    I still offer trussrods at no extra cost, but no one has taken me up on it yet.

  11. #11
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    Default Re: carbon fiber instead of truss rod

    I think that if folks put out thousands for a cool mandolin that they want the ability to adjust the neck just in case it gets a little out of wack. My Weber Fern is 5 years old and a few years ago it seemed a bit hard to play. I took it to our local high end shop and the repairman said it just needed a little adjustment on the truss rod. So I went home and took out my handy wrench and it's been perfect ever since. I think it is a great invention. My 1923 Gibson neck is still straight as an arrow!!! Just got a comment on that the other day at Old Time Music in San Diego. My point is.....it has worked for 86 years. Nick
    ntriesch

  12. #12

    Default Re: carbon fiber instead of truss rod

    I wonder: if CF had been discovered before the adjustable truss rod was invented, would we be having this conversation?

  13. #13
    Registered User amowry's Avatar
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    Default Re: carbon fiber instead of truss rod

    I'm certainly not saying that I think there's anything wrong with trussrods, and I agree that there's something to be said for tradition. Different builders also have different results with the same materials and techniques. I'm just saying that for me cf has yielded better results, and there's something to be said by the fact that more builders (and some of the best, not that I put myself in that category) are switching to it. It also corresponds better to my overall approach to building instruments that are stiff yet lightweight.

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  15. #14
    kestrel
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    Default Re: carbon fiber instead of truss rod

    H’lo Steve. How goes it?

    “If you cut out the trench, and then back-fill it with a steel rod, and maybe a wood filler strip on top of that, I don't think it is weakening the neck. The weak area, to me, seems that it might be the area you have to clear out around the truss rod neck (on the peghead area) so you can get a wrench around the adjusting nut.”

    I’m assuming that by “backfill it with a steel rod”, you’re referring to a truss rod. I’ve never used a truss rod, and I haven’t built all that many instruments, so I’m certainly not saying that I’m an expert. But, the reason I don’t use truss rods, is that I can’t make myself believe that by taking a quarter of the wood out of a piece that’s only 1-1/16” to 1-1/8” wide, and between ¾” and 7/8” high/thick (including fretboard thickness) at the nut, and not much greater than that halfway down the neck isn’t weakening the neck. I can’t see that a free-floating rod in the channel, even with a filler strip on top, will do anything but little to re-strengthen that narrow piece of wood. And, I certainly agree that hogging out the quantity of wood needed to give access to the adjusting nut in the already weakened bend, weakens it even more. I’m sure that this horse has been kicked well beyond recognition, and I don’t mean to belabor the issue, but the natural internal stresses in a piece of wood, unless reinforced by something capable of resisting those stresses, will move in the direction it wants to move. Removing a significant portion of that wood, and the stresses has even less to keep them from moving. Just watch a piece of wood close tightly behind the blade as you rip it on the table saw. IMO, a small steel rod, floating in open space, is not going to have much effect on those forces. A solid steel bar (or, as I prefer, carbon fiber), filling that slot, and glued tightly at all points will. No movement – no need for a mechanism to counteract movement.

    As far as being concerned about what clients want, I guess I’m lucky in that respect. Being retired, and having done the “Yassuh boss” thing for fifty-years, I build my instruments purely and simply because I love to. I build an instrument. If someone wants to buy it, I’ll sell it to him or her. If someone wants me to build them an instrument, and asks, “Do you use a truss rod?” I attempt to educate them into my way of reasoning. If I can do that, I build them an instrument. If I can’t, I tell them about all of y’all. Retirement and an independent attitude is a wonderful thing, but I can certainly understand where y’all are coming from.

    Truss rods? Carbon fiber? Steel bar? I suppose good and bad can be said in all directions. For myself, The Model “T” was a wonderful thing for its time. A Lear Jet will get you from New York to LA much faster, and far more comfortably. I’ll stick with CF, unless somebody can convince me otherwise.

    Gene

  16. #15

    Default Re: carbon fiber instead of truss rod

    Carbon fiber so easy to install .20 in wide CF bar is the same width as a Circular saw blade, cut the trench, little routing with a 1/8 inch drill bit, some west system epox done. It made the truss part of my first personal designed Mando easy. Glad to have read this thread.....it confirmed I did the right thing.

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  18. #16
    Mandolin & Mandola maker
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    Default Re: carbon fiber instead of truss rod

    My experience has been the same as Rolfe. 100 mandolins and mandolas made with CF in the neck, one has come back so a problem rate of 1%. That one I see regularly, and after a re-levelling the neck has remained straight, and that was about 5 years ago. The customer uses heavy strings and plays it hard. I think a lot of hoo ha is talked about with CF. Yes a truss rod will allow neck adjustments (how often do you adjust a trussrod? - probably never), but a truss rod is likely to make it more likely you will need the adjustment, and in some cases even a neck replacement. Some customers are misinformed, and I can put that right, others are just plain stubborn. The stubborn ones go away, which is probably a good thing for me since they are probably stubborn about other things as well. I have only ever used a truss rod once, in a longer scale mandola, and in that case I considered it to be necessary because of the longer neck.
    Peter Coombe - mandolins, mandolas and guitars
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  20. #17
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    Default Re: carbon fiber instead of truss rod

    I'm an early adopter of using carbon fiber, and I've remained a believer now for 33 years, though I use the stuff differently than I did at first. For longer necks, I do like the ability to adjust, but for short ones like mandolin necks, I think we can put just the right relief into the neck, fingerboard, and fret tops and simply be done with it. And besides all that, I believe that CF makes necks "sound" better. The necks are stiffer and more neutral tonally, and they suck less energy out of the strings. Just my opinion...

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  22. #18
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    Default Re: carbon fiber instead of truss rod

    When this topic came up a few years ago I went to the "eye candy section" of the Cafe and was blown away by all the super builders that use the adjustable truss rod. Really, check it out. Rick you just crack me up! Yep it's terrible how all the energy has sucked out of all those Nuggett, Apitius, Gibson, and so on mandolins!!! My old Gibson Snakehead sounds so wonderful the energy must have sucked the other way on that one. Nick
    ntriesch

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    Default Re: carbon fiber instead of truss rod

    Many makers follow tradition because that is what the market demands. It just has to have a red spruce top, or varnish, or a truss rod, or whatever the current fad is. I use red spruce because it is easier to sell than sitka spruce, though it doesn't necessarily sound any better. I also use engelmann, sitka, and redwood as I see fit.

    Peter Coomb's remark is right on, neck with a truss rod will more likely need adjustment than a neck with CF reinforcement, if installed properly. Over the years I have made 100+ mandolins, only a handful with adjustable truss rods, the majority with CF reinforcement, and a few with square steel tubing and of all these I have never had to adjust a CF reinforced neck but have had a few problems with the adjustable ones.

    I'm considering adding an adjustable rod to my future necks due to the market bias, even though I know it will mean a heavier neck, a weaker headstock, and a few more problems to deal with down the road. It makes me feel like I'm selling out to my better judgement, but it will help sales. You want chrome reversed Waverlys? Tuned and balanced inlays? Ported, polished, and turbo charged tuner buttons? Hey, I'm yer guy.

  24. #20
    kestrel
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    Default Re: carbon fiber instead of truss rod

    "Yep it's terrible how all the energy has sucked out of all those Nuggett, Apitius, Gibson, and so on mandolins!!!"

    And, who's to know they wouldn't sound even better with CF instead of the truss rod? Hmmmmmm.

    Great conversation, but I've got a third fret dot to tune on the mandola that's under way.

    Gene

  25. #21
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    Default Re: carbon fiber instead of truss rod

    I've seen numerous mandolins in my shop for setup/repair by now. I've seen vintage mandolins without truss rods, and vintage mandolins with truss rods. For the former, some had perfectly straight necks, while others had severely bowed necks. For the latter, the same was true. For those vintage mandolins with severly bowed necks and truss rods, adjustment worked in some cases, but didn't work in other cases; either the rods were adjusted as far as they would go, or the neck wood was just too inhomogeneous for the rod to eliminate all of the the humps and dips.

    Of the newer mandolins that I have seen in for repair, some had remained acceptably straight without adjustment, and some needed adjustment. Of those that needed adjustment, the rod did the job acceptably for some, while others retained humps and dips no matter what was done with the rod.

    All of the above points to significant variation in the properties of neck woods, even within the same species of wood. The remedy is either to select the wood based on measurements of Young's moduli, or employ some method of stiffening. If a luthier can not afford to reject more than half of his neck wood supply, that leaves the stiffening methods. I first used two parallel 1/8"x3/8" CF rods just under the fingerboard. The necks on most of my mandolins build with that system stayed straight, with the exception of one or two that moved a bit more than I would have liked. I have since changed to a different configuration of the CF that has been perfect so far. On F mandolins, I use both CF reinforcement and a truss rod, simply because I think that many people expect a truss rod on an F. On the other hand, if a customer specifically wanted an F mandolin with only CF neck reinforcement (i.e., no truss rod), I would be happy to build it that way. I am confident, on the basis of experience with all of my other mandolins, that a CF reinforced neck will remain stable and straight.

    http://www.Cohenmando.com

  26. #22

    Default Re: carbon fiber instead of truss rod

    I'm not a mandolin expert by any means, but my gut tells me that Rick is dead right (once again, as usual). I've eliminated the trussrod from my F5 design, and feel confident that I can build the right amount of relief into the FB and make the neck itself very very stiff. I've used CF rods in my guitars for years, and believe they help make the neck play more evenly (tonally) along the whole length of the FB than without them.
    Don Williams

  27. #23

    Default Re: carbon fiber instead of truss rod

    Well, since I am up against a new batch of necks for my flat "Traveler" mandolins, I might try one or two with CF instead of a steel adjustable truss rod. It's a shorter neck than most of you guys are using, so CF might even be overkill. I have used 1/8" X 1/2" CF as a back-strip on many of my pickguards for years, so I always have that size around the shop. If I taper it off a bit before it approaches the peghead, do you Users of the Carbon Fiber Clan think that is an appropriate cross-section of this stuff? My thought would be to run an 1/8" groove in the neck, perpendicular to the fretboard surface, and mount it that way.

    Probably overkill, but as my friend Van Hohe say, "Anything worth doing is worth OVER-doing".

  28. #24
    Registered User amowry's Avatar
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    Default Re: carbon fiber instead of truss rod

    I use a bigger piece (1/4" by 1/2"), but it's probably overkill. It's partly why I'm so confident about it, though. The material is light enough that I can use a lot and still have it be lighter than a single-action rod. I run it as low as possible in the neck, and continue it into the headstock.

    I agree with Rick about less energy loss with stiffer necks. I don't see any reason to expend energy on moving the neck when our main goal is to transfer that energy to the bridge.

  29. #25
    kestrel
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    Default Re: carbon fiber instead of truss rod

    Steve -

    I was using 3/16 x 1/4" bars in my mandolins, but am concentrating on mandolas, now, and have switched to the 1/8 x 1/2" that you're talking about. With both, I run my channel all the way through my tenon, and straight out into the peghead, cutting the angle on the bar to the flat of the top peghead surface, under the head plate. I figure that adds strength to the potentially weaker area at the angle from the nut. Guess I couldn't do that if I weren't using a head plate.

    Gene

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