DIY Carbon Fiber reinforcement?

[micguy]

Making your own carbon fiber rods as an experiment is something I applaud. We should all try things.

However, before you put it into your instrument, I reccomend you buy a commercial one, measure the bending stiffness of both (you can do this with feeler gauges by measuring the deflection under load), and then install the winner into your bass. I'll bet the commercial one packs its fibers tighter, and as a result, will be stiffer - probably byt a good margin. Having messed with composites before both on my own and having used commercially made ones in my work, I'm pretty sure I can't make a carbon fiber rod at home that will compete with the commercially made ones.

 

[micguy]

Titanium is better and won't break.

Titanium is considerably heavier - a density of 4.5 vs 1.6 for carbon fiber. Wood is lighter than either, so adding either of those materials as a stiffener adds mass to the neck. If we start with a density of about .6 (Maple), then the additional weight from adding a reinforcement rod (here you subtract the .6 from each of the densities) with the same cross section is 3.9 times greater with Titanium. So, in at least that way, it's not better.

I sincerely doubt that a carbon fiber reinforcement inside a bass guitar neck will ever break in any circumstance that wouldn't destroy the whole neck anyway.

 

[dwizum]

I think it's worth pointing out that the design (where and how you place the carbon in the neck) is as important as the carbon product itself. Not to mention knowing what your actual goals are for your neck.

You certainly can't take raw carbon tow or fabric, go into your basement workshop, and make an identically-dimensioned bar that outperforms an off the shelf bar. But a 1/8" by 3/8" (or whatever) bar is not always the best shape to use in a bass neck.

Starting with raw tow or fabric gives you a much higher degree of flexibility in terms of how much carbon you use and where you place it. That's the important part here. Bars are used in bass necks because they're convenient. Not because - for a bass neck - it's the best option possible. If you want fine control over the end product, making it yourself from raw materials is the better option in this case.

 

[Dirk Diggler]

If I recall the cloth technique was used in Parker Fly's to reinforce the skinny neck/body joint area.
That seems like the perfect use for CF cloth.

Heck while we're at it, let's just add a couple more truss rods instead!
Sorry I joke.

Would love to see what happens when you give it a try, good luck.
Dirk

 

[Gilmourisgod]

I drank the coolaid on CF bars. Used in 2 necks now, and both seem really stable, but still adjustable. The rub is, I have no idea how much the CF bars contributed, other than anecdotal evidence, and how much was the laminate construction, wood choice, etc. I can say they did no harm anyway. The CF bars are pultruded in some kind of resin, I don’t know what percentage of that is actually CF. In the interest of Science, the OP must Proceed!

 

[dkelley]

Different question - When Stuart Spector talks about "Graph-feet" is he saying "Graphite" in a very unusual (erm, mispronounced) way? Or is the graph"feet" he's talking about a common or accurate term to describe the CF rods as a whole material made from CF and epoxy?

See I don't actually now what "graphite" is (like the stuff that we use in pencils to draw with, that we make black nuts and saddles etc from, and that we use in powered form in nut slots to "lubricate" the string in the slot).... but I'm ASSumine the common graphite used for pencils etc is different from a combination of Carbon Fiber and Epoxy.

 

[dwizum]

He's just pronouncing the word funny. Not sure if it's on purpose or not. He is a pretty quirky guy!

The bars he's using are pretty much the same exact pultruded bars that are commonly used by hobby builders and many other manufacturers. They're carbon fibers embedded in special heat cured epoxy with 100% of the fibers aligned along the length of the bar (as opposed to products made from woven or expanded fabric which usually have some fibers in other alignments to get a different performance result in the end product). Those bars are good in terms of getting a nice uniform product that's made at an optimal ratio of carbon to epoxy, and the fibers are very well aligned along the length of the bar. But you're limited to to the dimensions and shapes available, and you're limited to unidirectional orientations.

 

[Richardnbm]

Titanium is considerably heavier - a density of 4.5 vs 1.6 for carbon fiber. Wood is lighter than either, so adding either of those materials as a stiffener adds mass to the neck. If we start with a density of about .6 (Maple), then the additional weight from adding a reinforcement rod (here you subtract the .6 from each of the densities) with the same cross section is 3.9 times greater with Titanium. So, in at least that way, it's not better.

I sincerely doubt that a carbon fiber reinforcement inside a bass guitar neck will ever break in any circumstance that wouldn't destroy the whole neck anyway.

You can't feel the difference and you better have a mask on for carbon fiber. Ok smart boy.

 

[Beej]

Different question - When Stuart Spector talks about "Graph-feet" is he saying "Graphite" in a very unusual (erm, mispronounced) way? Or is the graph"feet" he's talking about a common or accurate term to describe the CF rods as a whole material made from CF and epoxy?

See I don't actually now what "graphite" is (like the stuff that we use in pencils to draw with, that we make black nuts and saddles etc from, and that we use in powered form in nut slots to "lubricate" the string in the slot).... but I'm ASSumine the common graphite used for pencils etc is different from a combination of Carbon Fiber and Epoxy.

I think if Stuart Spector started talking about Carbon Feeber, we'd know for sure...

 

[Richardnbm]

Well I guess I better focus on playing some music now.

 

[micguy]

You can't feel the difference and you better have a mask on for carbon fiber. Ok smart boy.

People complain a lot bout how much weight steel bars add to Warmoth necks. Titanium is half the weight - it’ll be lighter, but still noticeable.

I highly doubt that gluing a carbon bar into a neck is going to generate a cloud of dust.

 

[MPU]

Steel, titanium aluminium or carbon rods below the fretboard (as these rods are usually laid) are still not on the right place mechanically. A couple of tows epoxied under the truss rod, closer to the back of the neck has more effect on the way the neck behaves. That's explained by Bruce on the first page. I've made neck both ways and tows seem to work better. They are cheaper, jus as easy to use as rods and lighter if that few grams really matter. This thread is about carbon fiber reinforcement, let's keep it so.
As much as I hate to say this I say it still. It's two different things to read from internet and do and test something. There's quite a few of us builders that have used carbon fiber to make necks. We base our opinions on our experiences. That, in my world, is more relevant than something read or seen somewhere in the net.

 

[Dirk Diggler]

Maybe he was referencing Graphene perhaps?
Graphene - Wikipedia

By the way I solved my needs for extra neck reinforcement by multi laminate neck woods that are high density.
I have only ever needed a single truss rod in my builds, even 6 string multi-scale basses.

And I totally agree with MPU, talk is cheap, actual experience wins every time.
Hypothetical conversations have their merits, but there's nothing like experimentation.

Good luck,
Dirk

 

[Beej]

That's not how they make carbon fiber rods. Titanium is better and won't break. You can order them from KTS but you can get them from a metal stock supplier in the USA cheaper. Titanium sounds better. MTD uses it on thier American customs. These rods a inexpensive and safer to work with than carbon fiber.

I've used titanium stiffeners from KTS, but have gone back to CF and aluminum. I'm just using up my aluminum and then will go back to CF for the long haul. Lighter and stiffer than titanium, and around 1/4 the cost. I pried some CF bars out of a neck to try to reuse them once, and when it finally gave way, it was the epoxy surrounding it that shattered and released the CF rod with so much kinetic energy that it flew up and stuck in the ceiling drywall! Holding a titanium stiffener and a CF one, I can bend both to deflect a little, but it's easier with the titanium. In terms of shop safety, everything is better with a dust mask.

 

[Gilmourisgod]

I’ve tried bending the CF bars by hand along the vertical axis.... nope, not with my weak little mitts anyway. The ones I’ve been using are from BBG, not cheap at $15 each, but nobody else seems to have them in stock. At 3/8” deep, they extend into the bottom 1/3 of the neck, so the bottom edge must be acting in tension.

 

[dwizum]

I bet CTS can beat luthier suppliers on price:

Homepage - CST The Composites Store, Inc.

They have a huuuge selection of sizes and shapes of pultruded rods and tubes. If someone wanted to try an "under the truss rod" install but didn't want to start with raw tow, you could get a really thin profile shape from them and just glue it under the truss rod.

 

[Beej]

I bet CTS can beat luthier suppliers on price:

Homepage - CST The Composites Store, Inc.

They have a huuuge selection of sizes and shapes of pultruded rods and tubes. If someone wanted to try an "under the truss rod" install but didn't want to start with raw tow, you could get a really thin profile shape from them and just glue it under the truss rod.

Thanks for that, I hadn't seen these folks before, they have a wide variety! Prices are around the same as Dragon Plate, so that's cool too. I'll have to order some

 

[Beej]

Both related and unrelated to this thread, I've recently used a titanium/steel hybrid double acting TR on a guitar build and I really like it so far. It's very lightweight compared to the all steel version when hefted in the hand. The threaded rod and welded nut are steel, but the top strap and blocks are titanium - I'm a little concerned about galling between Ti/Steel at the threads, but we'll see. I installed it in a removable fashion just in case.

Speaking of titanium, KTS apparently is again back to making single-acting titanium bass trussrods, (calling @Slidlow ) but they are not shipping right now due to how Japan is handling Covid. One of the canadian suppliers I use has been showing them in stock again.

 

[dwizum]

I've been buying carbon parts from CTS for 20+ years. They're a great vendor. For cloth and epoxy resin, I also like uscomposites.com although they don't sell any pultruded parts. Their house brand epoxy is really good and cheaper than most of the common brand names.

 

[Slidlow]

Both related and unrelated to this thread, I've recently used a titanium/steel hybrid double acting TR on a guitar build and I really like it so far. It's very lightweight compared to the all steel version when hefted in the hand. The threaded rod and welded nut are steel, but the top strap and blocks are titanium - I'm a little concerned about galling between Ti/Steel at the threads, but we'll see. I installed it in a removable fashion just in case.

Speaking of titanium, KTS apparently is again back to making single-acting titanium bass trussrods, (calling @Slidlow ) but they are not shipping right now due to how Japan is handling Covid. One of the canadian suppliers I use has been showing them in stock again.

Hi @Beej, I haven't used the KTS single acting rod yet. I was fortunate to get a few of their double acting ones before they discontinued making them. Two are going into my ebony necked six string that I have been pining to get finished but other work keeps getting in the way.