Guitar Techs - Correcting with a neck with a backbow?

[Chris of Arabia]

I've been asked to take a look at a friends Vintage Series Tele Custom that is experiencing a lot of fret outs / buzzing. He'd already told me that someone had already identified it as having a backbow to the neck and that he'd adjusted the truss rod to no avail, but I said I'd look at it anyway. Sure enough, there is no string relief to it at all (strings rest on the frets), and I found that the truss rod nut was actually loose, with no tension at all on it.

I've already tried supporting it at the headstock and heel, then clamping it near the centre for a few hours, but there is no sign at all that it is having any effect - I can see the backbow with the naked eye by sighting along its edge. There's no sign of any twisting btw. Has anyone had dealings with a neck like this and how did you fix it? Maybe I just need to clamp it for longer, or with more pressure, but I'm getting the impression that this one just doesn't like the lack of humidity here.

Anyone got any pearls of wisdom?

 

[BrianS.]

Re: Guitar Techs - Correcting with a neck with a backbow?

...just doesn't like the lack of humidity here.

More humidity would cause the wood to swell, and most likely make the backbow worse. For that guitar, I'd recommend getting a new neck.

 

[Chris of Arabia]

Re: Guitar Techs - Correcting with a neck with a backbow?

I should have mentioned that the neck has a rosewood fingerboard, so it's possible the maple has contracted more than the rosewood. I had considered whether to tell him he needs a new neck though...

 

[Bludave]

Re: Guitar Techs - Correcting with a neck with a backbow?

Replacing the neck in some case is the only option that will work. Clamping the neck under heat will help but depending on how bad it is it may not create the desired effect. I had a Strat that had a beautiful flame neck with a RW board, but after about a month the neck started to bow(not backbow), I was able to get by but the action was a bit high. After a few years I decided to try and adjust it but the truss rod was doing nothing, just spinning so I would up replacing the neck.

Not sure if you have a way of heating up the neck but that will definitely help the neck heat can be its friend or foe depending on which way the neck would need to go. With a back bow I would consider putting heat on the neck and clamping both ends possibly bu putting somthing under the fingerboard to bend it in the direction you need it to go. Leave it clamped up for several days and then see how it will come together. If this doesn't work then a new neck may be the only option.



This video is showing a techniques to straighten a forward bow in a neck but you should be able to just flip the neck over to help a back bow.



This may be more of what may need to be done...

 

[AlexR]

Re: Guitar Techs - Correcting with a neck with a backbow?

?? Convince him that he needs heavier strings, and put a small shim in the neck pocket to help with some relief.

 

[GuitarStv]

Re: Guitar Techs - Correcting with a neck with a backbow?

?? Convince him that he needs heavier strings, and put a small shim in the neck pocket to help with some relief.

Lol, that's what I was thinking. Convince him that the best tone is from .014 - .85 strings tuned to standard.

 

[ItsaBass]

Re: Guitar Techs - Correcting with a neck with a backbow?

It needs a replacement neck, unless you want to do a lot of work to it. Not having to do hard-core repairs, or even re-frets, is one of the great advantages of bolt-neck instruments. I'd take advantage of it in this case, unless it is a really valuable instrument that would be hurt by having non-original parts.

 

[Mr. B]

Re: Guitar Techs - Correcting with a neck with a backbow?

Have you tried tightening the truss rod just to see what happens? I know that would be adjusting the wrong way, but I'd be interested to see if there was something wrong with the truss rod, if it were mine.

 

[Dr. Vegetable]

Re: Guitar Techs - Correcting with a neck with a backbow?

 

[Chris of Arabia]

Re: Guitar Techs - Correcting with a neck with a backbow?

Well before I go down the bakeware route, I've give it another go at clamping it, but for rather longer this time. I picked up an idea or two from the 2nd vid Bludave posted. If that doesn't work, then I'll discuss the 'Flaming Ovens From Hell' option with the owner, but that'll have to wait until he gets back into KSA; little bugger's on holiday again...

 

[BrianS.]

Re: Guitar Techs - Correcting with a neck with a backbow?

Whatever fix you try (other than replacing the neck), don't be surprised to see the backbow reappear over time.

 

[Zerberus]

Re: Guitar Techs - Correcting with a neck with a backbow?

Heat press as some have recommended, or replace it.

If the bow is slight without strings, once could replane the fretboard and refret the neck.

If the bow is really really minor like on my Wrath, heavier strings are indeed an option. The Wrath was back bowed about 1mm at the nut w/o strings, barely enough to sight it along the fretboard /neck plane. But with 13-60 she plays just dandy, even though I normally only use 12-52.

 

[rumblebox]

Re: Guitar Techs - Correcting with a neck with a backbow?

Try huge strings for a few months before doing surgery.

 

[Chris of Arabia]

Re: Guitar Techs - Correcting with a neck with a backbow?

Let's leave it like this for a few days and see what happens...

 

[octavedoctor]

Re: Guitar Techs - Correcting with a neck with a backbow?

If the bow is slight without strings, once could replane the fretboard and refret the neck.

That's exactly what i would do. Heat treatment is a waste of time. It sometimes works if you have a guitar with a separate fingerboard and you can get the glue line to shift but most of the time you'll end up making it worse.

I had this with a '76 Martin recently. Fixed, non adjustable reinforced neck. No amount of heat treatment was going to move that bad boy. I did two things; I pulled all the frets out (having just refretted it only to find there was no truss rod -doh - I would rather have pulled my own teeth out), opened out the fret slots to relieve some compression on the front of the neck, reducing it's stiffness, then shaved the fingerboard very gradually from the middle out towards each end. Worked a treat. Customer said he's never been happy with it and it had no bass response and suddenly it sounded like a D35 should, apparently. I put it down to the reduced stiffness of the neck enhancing the bass response.

 

[octavedoctor]

Re: Guitar Techs - Correcting with a neck with a backbow?

Let's leave it like this for a few days and see what happens...

View attachment 47591

I think you're on the right track with that but I'd use a much deeper shim than what you have there, you really need to pull it round. Remember that as soon as you take it out of the clamp it will flex back, you just need it to return to a less bent profile than it was before. You really need to push the elastic limit a bit. This technique has worked for me several times in the past, but cold, not with heat or steam.

 

[uOpt]

Re: Guitar Techs - Correcting with a neck with a backbow?

I would make sure that the truss rod isn't stuck.

Does it do anything if you tighten it?

 

[Chris of Arabia]

Re: Guitar Techs - Correcting with a neck with a backbow?

It's definitely not stuck. At the moment whilst it's clamped I have it loosened right off. I've also given the nut end a couple of smart taps with a plastic faced mallet to just ensure nothing is stuck. It's still clamped at the moment, but I shan't be releasing it for a few days yet.