Thinking of carbon fiber truss rod - tips, pointers, advice?

[fscotte]

Read the merits of using a CF rod and would like to try it on my first built. Just a few questions here for those who've been using CF.

1) I'm planning on profiling the neck ala the Siminoff plans. Seems to be the standard 1 1/8" wide neck and V shaped. Is this OK with CF or should I make the neck a bit beefier? My neck is vertical grain curly maple.

2) If using the profile as mentioned above is ok, what size CF should I use?

3) How far back towards the nut should the CF be? Where does it stop?

4) Should the CF rod fit as tight as possible in the slot or should it just press down in with finger pressure?

5) Should the neck plane be absolutely flat or should there be a slight backbow?

- I'll be using the standard D'adarrio medium tension strings.


That's all the questions I have for now. If there's any other tips or advice please feel free to send it!

[Michael Lewis]

Do not induce any back bow!!!!

The CF bar stock I use runs out under the overlay of the headstock. Cut it at the headstock break angle and you are good. It should fit closely into the slot, should not have to be forced in. Measure your neck at the narrowest part to see if you have enough room to put a 1/4 X 1/2" bar into it perpendicular to the fingerboard gluing surface. It should fit but you have to make sure, and you shouldn't have to make the neck bigger than what you would like to play on.

[Rick Cadger]

Wear a mask if you cut or sand that stuff.

[Lefty Luthier]

Michael's advice agrees with my practice though I normally use a 0.125 x 0.50 spline. One thing that I do in addition is cut the channel about 0.10 deeper than the spline and overlay with wood matching the neck since hide glue does not stick very well to CF.

[fscotte]

Wow, thanks. Good info.

[Avi Ziv]

......One thing that I do in addition is cut the channel about 0.10 deeper than the spline and overlay with wood matching the neck since hide glue does not stick very well to CF.

Byron,

what glue do you use for the thin wood filler over the spline then? Something like epoxy?

Thanks

[Charles E.]

I do the same thing but leave the wood filler proud of the neck surface and glue it all together. I used to use epoxy but after a recent thread here, I did my last one with Maxi-Cure thick CA. After it is cured I plane down the filler with a block plane.

[Lefty Luthier]

Byron,

what glue do you use for the thin wood filler over the spline then? Something like epoxy?

Thanks

The squeeze out of epoxy is always more than sufficient to bond the cover strip. I press it flush, wipe off the excess and clamp under a 1 x 1 aluminum angle.

[FletchB]

All of the above. I prefer Michael's larger dimensions, 1/4 X 1/2. I used 7/16" square while I had it. Make a drawing of your neck profile (cross section) down around the first fret and nut, including the space you want to occupy with the truss rod. It will give you an idea of how much wood is left outside of the truss rod.
Here is a source I recently found with good prices (best I've seen)... http://www.goodwinds.com/merch/list.shtml?cat=carbon.solidflatcarbon
Anybody know anything about the rigidity of the rod we get from Stew Mac/ LMI etc. Seems like there must be different grades depending on fiber content (weave density) etc.?

[FletchB]

I cut with a hack saw, and usually blue tape the cut to keep the ends from fraying. Carbon Fiber eats blades for lunch, even carbide. I wouldn't advise power tools as you don't want that dust in the air. Wear a dust mask.

[fscotte]

Wow, now you tell me. :crying: I already bought a rod from LMII and now you show me those awesome prices. Well, at least I know where I'll be buying them next time!