6K TOW Carbin fiber thread... genius!

[Prostheta]

I missed the opportunity to see them in Helsinki earlier in the year. Then again, we caught Rammstein in Tampere. So many good bands coming from Germany....I digress.

Re: "how can carbon fibre reinforce a neck". Generally it's stiffer and lighter (I'm sure there are exceptions) than the equivalent cross section of wood along the grain. I believe this is the fundamental principle behind the idea. @Cycfi made carbon fibre truss rods which i think is exceptional thinking.

[Bizman62]

2 hours ago, Prostheta said:

Generally it's stiffer and lighter (I'm sure there are exceptions) than the equivalent cross section of wood along the grain.

To be nitpicky, it's stiffer compared to the mass and size than most any wood.

To be even nitpickier, does my comment above bring anything new to the discussion?

[Prostheta]

Probably? My experience with reinforcement is carbon fibre as lengths of either square or round cross-section, solid or hollow. I was implying that the wood they are replacing (as stiffening bars) is less stiff than the composite that is fitted in their place. The part about cross section was intended to cover hollow, since the volume isn't the same in this instance, especially when fitting an I-beam which (if I recall) is the stiffest cross-sectional reinforcement for the mass.

[Prostheta]

I had to review this thread since I sort of came in late in the conversation and missed the main points made.

Stretching the fibre towards the point where it will immediately go into tension would seem to add to the final composite in my mind, so the pultrusion process makes sense. Carbon fibres are strong under tension whilst the binding epoxy is strong under compression, so in its rest state you'd maybe want the material to be at the ideal balance between the two. I doubt you'd get much stretch out of carbon fibre once bound in epoxy, because after all, epoxy still has strength in tension, or enough to prevent the carbon moving around or otherwise deforming to get any "remaining stretch" out of weave. I'm probably completely wrong, but stretching - or at least removing any slack - seems to be a positive gain.

Referring back to my example of Cycfi's carbon fibre truss rod, I would imagine that pultruded material would be working right at its key areas. I wonder how the numbers would compare between the traditional type and carbon fibre, dumbed down to simpler things I can understand....

[mistermikev]

kind of makes me wonder... how much tension is on that carbon fiber when it is pulltruded?  what if you took carbon fiber tow... cut a 3/32 grove on the back side of a neck... clamped it down and pulled it tight (just by hand) and then use reg epoxy to seal it in place?

the carbon fiber they use on fishing rods - they don't put any tension on that... they just roll it up around a rod.  then again, maybe that fabric already has epoxy and has tension... seems pretty limp in the video.  yet they heat it up... and all of the sudden it's hard.

and another thing... how well does carbon fiber/epoxy bond to wood?  what if you used carbon fiber as a laminate in a multi lam setup?  just the carbon fiber fabric?  used it sort of like an accent strip?

just a childs' meandering here but something I wonder about.

[Prostheta]

Regular epoxy is plastic and deforms easily, removing the whole "strong under compression" aspect of why carbon fibre composites rule. If you used a correct epoxy, I imagine it wouldn't need much pulling. Just enough to remove slack rather than warping the thing.

[mistermikev]

Just now, Prostheta said:

Regular epoxy is plastic and deforms easily, removing the whole "strong under compression" aspect of why carbon fibre composites rule. If you used a correct epoxy, I imagine it wouldn't need much pulling. Just enough to remove slack rather than warping the thing.

tell me more of this.... "correct ep-oxy"

[Prostheta]

You mean ee-poxy? 

The "correct" ee-poxy is one appropriate for the end use!

[mistermikev]

Just now, Prostheta said:

You mean ee-poxy? 

The "correct" ee-poxy is one appropriate for the end use!

well sir... I mean specifically... what is in your view the correct epoxy for this application?  mikro mentioned that it would be a heat cured resin... is there such a think available to reg joes like myeslf?

[Prostheta]

Not sure because this isn't an area I'm too familiar with. I understand the uses of the finished product, but not so much the methods used to create them. I've used pultruded rods in necks before, and they're a nice off the shelf "thing". As for access to epoxies, well, I'm sure that if you're willing to buy a bucket or larger then anything is available. It might be that you can't get it in human quantities.

[mistermikev]

Just now, Prostheta said:

Not sure because this isn't an area I'm too familiar with. I understand the uses of the finished product, but not so much the methods used to create them. I've used pultruded rods in necks before, and they're a nice off the shelf "thing". As for access to epoxies, well, I'm sure that if you're willing to buy a bucket or larger then anything is available. It might be that you can't get it in human quantities.

hmm, well the search goes on then!!

[Prostheta]

I forgot about the heat-cured part. This is perhaps a property engineered into the epoxy for the process rather than letting it chooch on its own time. Curing in the mould or die through applied heat works from a manufacturing viewpoint so the thing is a continuous process. Given that pultruded products are dimensionally very consistent, this would seem an advantageous choice.

[mistermikev]

17 minutes ago, Prostheta said:

I forgot about the heat-cured part. This is perhaps a property engineered into the epoxy for the process rather than letting it chooch on its own time. Curing in the mould or die through applied heat works from a manufacturing viewpoint so the thing is a continuous process. Given that pultruded products are dimensionally very consistent, this would seem an advantageous choice.

obviously doing it 'from home' one would expect the exact consistency and rigidity that a commercial process would yield... as all things it would have that downside... with the upside being the potential for a more malleable application.  if the rigidity was comparably 'close enough'.

[Prostheta]

I'd hazard that it would be very hard to match the properties of a manufactured pultruded section using home gamer methods. You might get 50% of the way, and perhaps - if you run the numbers - that might still meet your end goal. Can you quantify the objective in this manner? I'd say that consistency is the main enemy. A section might have properties that vary in spots which may be less than predictable. This is a rabbit hole. I've always been interested in laminating carbon fibre as pinstripes 3-4 layers thick. That would provide stiffness, however the final finish would need to shield your fingers from the abrasive cutt-y end bits!

[mistermikev]

Just now, Prostheta said:

I'd hazard that it would be very hard to match the properties of a manufactured pultruded section using home gamer methods. You might get 50% of the way, and perhaps - if you run the numbers - that might still meet your end goal. Can you quantify the objective in this manner? I'd say that consistency is the main enemy. A section might have properties that vary in spots which may be less than predictable. This is a rabbit hole. I've always been interested in laminating carbon fibre as pinstripes 3-4 layers thick. That would provide stiffness, however the final finish would need to shield your fingers from the abrasive cutt-y end bits!

I'm not familiar with this engineering term "cutt-y"... please elaborate (hehe). 

well I was thinking that if you did a gloss finish over the top it would be less 'cutt-y".   just spit balling here. 

more I think about it carbon fiber rods seem like much less effort... but the original premise was that you could use TOW carbon fiber thread, and potentially reinforce a neck 'enough' without adding all that much carbon fiber and more importantly the amount of resin you'd put in your guitar would be lessened.  this was all spurred on by a thread I was reading over at talkbass where an experienced gentleman (bruce) uses 2-12 threads under the truss rod, puts in a filler stick, then the truss rod.  It is essentially a cheaper way, and according to bruce - adds enough rigidity without adding all that plastic/resin.

[mistermikev]

i guess if one made their own truss rods... a carbon fiber wrap on the rod might be a good idea.  it'd be ideal to have that carbon fiber occupying all the 'air' space in a double action truss rod.

[Prostheta]

Talk to Cycfi. He's a smart guy and very open with his ideas. No point in reinventing the wheel that was recently reinvented

[mistermikev]

4 minutes ago, Prostheta said:

Talk to Cycfi. He's a smart guy and very open with his ideas. No point in reinventing the wheel that was recently reinvented

well then... let my start by building a shrine in my mind... by reviewing the threadsy of cycfi...

[Prostheta]

https://www.cycfi.com/2010/10/cf-truss-rod/

[mistermikev]

14 minutes ago, Prostheta said:

https://www.cycfi.com/2010/10/cf-truss-rod/

a faskinatin' read.

[mistermikev]

just a follow up here... I spoke to syfi... and he agreed that the TOW threat method would not add meaningful rigidity.  I guess we all kind of knew that, but just thought I'd follow up.

[Prostheta]

It's always a good thing to round up ideas and document how they play out. Too many forum threads around the Interwebs hit one snag and go cold forever with no meaningful closure. Where do you think you might take this, if anywhere?

[mistermikev]

9 minutes ago, Prostheta said:

It's always a good thing to round up ideas and document how they play out. Too many forum threads around the Interwebs hit one snag and go cold forever with no meaningful closure. Where do you think you might take this, if anywhere?

well, the takeaway for me is that if one wanted to do something like this you'd have to address the need to put tension into the carbon fiber.  that really complicates it for me. 

I think what I'll end up doing is buying some of the thinner pulltruded carbon fiber rods and perhaps do a 1/16 route that is deeper.  I just don't want to put a lot of "anything other than wood" in a guitar if I don't need to.  The one thing I think I heard from many sources is that the typical 1/4 x 1/4 carbon fiber reinforcement is more than anyone needs.  so... perhaps I'll snag some 1/16 x 1/4 rods and try that out.  this whole thing came from me thinking about a 5 string bass (my next) that is a purpleheart/maple lam.  probably going to be pretty solid as is, but I'm wanting to do a really shallow profile and I'd like to maintain as much rigidity as I can without adding any more carbon fiber than I need. 

[Prostheta]

So that's a thing then.

Well, CF in a neck is no bad thing. I recall that David Myka did a test many years ago where he made a neck with LOTS of pultruded tubes replacing the wood. The comment was that it was very bright sounding. I wouldn't say that's a bad thing, just a thing to quantify when juggling your parameters. I'm of the opinion that a simple wooden neck can always be better whether through basic lamination of the same wood to achieve a more stable growth ring orientation and symmetry, lamination of different woods and materials to achieve the same and bring together a variety of tonal qualities, or flat out going super tech and dropping in everything....in reasonable balance.

Like you've heard other people say, a couple of small reinforcement bars are more than enough. You can easily make a neck too stiff and unresponsive. Strings need to pull in a little bow for fret clearance. Man, you know all this. haha 

[mistermikev]

Just now, Prostheta said:

So that's a thing then.

Well, CF in a neck is no bad thing. I recall that David Myka did a test many years ago where he made a neck with LOTS of pultruded tubes replacing the wood. The comment was that it was very bright sounding. I wouldn't say that's a bad thing, just a thing to quantify when juggling your parameters. I'm of the opinion that a simple wooden neck can always be better whether through basic lamination of the same wood to achieve a more stable growth ring orientation and symmetry, lamination of different woods and materials to achieve the same and bring together a variety of tonal qualities, or flat out going super tech and dropping in everything....in reasonable balance.

Like you've heard other people say, a couple of small reinforcement bars are more than enough. You can easily make a neck too stiff and unresponsive. Strings need to pull in a little bow for fret clearance. Man, you know all this. haha 

right on, some good fact-lets there (I've heard many complaints about teh sound of carbon fiber, then again flea seems to make an entirely carbon fiber neck sound pretty good so... grain of salt).

I have two 5 strings right now... and don't really care for either.  they both are solid maple and are under constant strain to maintain the super low action I like.  I think I'm probably most of the way there just going with a 7 piece lam w opposing grain and an ebony board... and perhaps I'm jumping the gun thinking that that on it's own won't be enough to get me rock solid stability with a thin profile... but I'd hate to be wrong!