Neck relief issues...

[DalyTek]

I got an old (1985) Carvin V220 in a mass trade and have been working on setting up and am having a large problem.
First off, it's a "set-thru" neck I believe. It LOOKS like neck-thru, but I think it's actually a glued-in neck that's carved that way.
It's all maple (neck & body) with an ebony fretboard and a Kahler trem, brass nut and behind-the-nut lock.

Anyway, I took off the old grungy strings and put on my staple on all guitars: Elixir 10s.
I was getting buzzing all over the place. (Not open strings, just fretted notes. Nut depth is not the issue.)
Holding down the first and last fret and using the string as a straight edge, the string touches every fret between.
I went to go loosen up the truss rod a bit to allow the strings to pull the neck a little more into a forward bow and found the truss rod is completely slack already.

The only thing I could think of to try was to put it face-down on a desk, pinning the neck down and allowing the remaining neck (from about 12th fret on) and body to hang over the edge of the desk.
I was hoping the sheer weight of the body (it's pretty heavy!) would cause it to regain some of it's forward bow. I left it like that, undisturbed, for 3 days.
I restrung it yesterday (with the Elixir 10s) and found nothing had changed.

Obviously, I can try a thicker gauge of strings to put more tension on the neck, but I really only like 10s, plus I would probably have to modify the nut for that and don't want to go there.
What else can I do? This is a great feeling guitar if I can just get the neck relief issue resolved it will be a great player.

[jdr94]

Tighten the truss a little and try to raise the saddles maybe?

Its been years on years since I had one, but I remember the strings saddle to the nut had that Les Paul angle. That was one of the things I didnt like. I like the flat Strat profile. Hope that makes sense.

[Axewielder]

Backbow with a one-way truss rod is tough. In fact, it's one of the worst things to be afflicted with on a guitar. With the heavier gauge string solution off the table, about the only thing left is a replane and refret (if this is in fact diagnosed correctly).

[DalyTek]

That's definitely what's going on. I'm usually really good at doing setups. I guess I'm gonna have to pop some 12s on there or something. What I wonder is if I put thicker strings on it and maybe over-tune it, if I can bring it into a forward bow with some method like that....is there a way to make it stay that way?

[RobRR]

You can put some heavy gauge strings on it, though I would leave them on for at least a week... Id probably go with 13's.

[DonP]

In Dan Erlewine's book, he uses a clamping solution to correct back-bow.

[DalyTek]

In Dan Erlewine's book, he uses a clamping solution to correct back-bow.

Thanks Don! I went and grabbed my Erlewine book and found the spot that shows that. It doesnt say how long you need to leave it clamped for it to set though...

[j2379]

try this, string it up with 11's or 12's put a slide or lighter between the strings and fretboard, somewhere between the 5-7 fret and leave it be for a few days.

[DonP]

I keep thinking about this. Would it be good or bad to try adding humidity? You are in a dry climate, so it would have an impact, but I think it might make things worse. I would think adding humidity would make the neck want to back-bow even more.

[ulijdavid]

I have seen some instances where you clamp and induce the bow as has already been stated, but also wrap the neck with a heated blanket. I think this may fall into what DonP was getting at. Add some heat, but not the humidity. I would probably try the heavier strings first though - or try emailing Dan Erlewine.

[DalyTek]

I did try clamping it for a couple of hours, and it didn't seem to help. I don't think I need to add heat. It's summertime in Arizona.
Humidity might help possibly. I would think that would soften up the wood, clamp it when it's humid, then release when it's dry again?
How exactly do I add humidity? A Vaporizer or something?

[Axewielder]

IIRC, the Erlewine clamping technique was all about helping the neck into the right position before adjusting the truss to lessen the torque required. It wasn't targeted at the loose one-way truss situation.

[DeathThrashAttack]

tighten the truss rod a bit, then clamp for a least a day, then adjust the truss rod again and restring.

[ginsambo]

This will sound stupid but have you tryed turning the trussrod the other way for a bit more to see if it'll bite? Most through necks have two way truss rods, I should think a Carvin would have one? Only I had same problem with my BCRich, truss totally slack for almost a turn and a half/two turns, very loose and knocked when you tapped the back of the neck, put the fear of God into me as I figured if I undid it any more I'd undo it. Bit the bullet and slackened it off some more and it starting biting and the neck started bending forwards. Magic!

[DalyTek]

This will sound stupid but have you tryed turning the trussrod the other way for a bit more to see if it'll bite? Most through necks have two way truss rods, I should think a Carvin would have one? Only I had same problem with my BCRich, truss totally slack for almost a turn and a half/two turns, very loose and knocked when you tapped the back of the neck, put the fear of God into me as I figured if I undid it any more I'd undo it. Bit the bullet and slackened it off some more and it starting biting and the neck started bending forwards. Magic!

Oh how I wish this was the case. I thought the same thing. I continued turning it counter-clockwise until the nut came completely off the threads. You would think that a USA-made neck-thru Carvin from the mid-1980s would have a two-way truss rod!