I've been lurking on this forum for a while, browsing through all of the useful info posted here... I've been making acoustic instruments for fun for a while now and recently came across a possible repair project...
A friend picked up this old Yamaha FG-340 cheaply a while back. It's not really playable at the moment as the neck is warped. (the relief with no string tension is about 0.016”/0.4mm) Someone has taken the fretboard off and reglued it (there are some gaps under it at the nut end, and lots of chipping of the lacquer where it meets the fretboard). It looks like when this was done, some glue seeped into the truss rod as this is jammed – and the truss rod nut is all chewed up...
I was thinking of getting a clothes iron and laying it on the frets to heat up the neck, then clamping it in such a way so as to remove this warp... But I'm not sure whether this would provide sufficient heat to do the job. I'm also concerned about it melting the plastic bindings which run along the fretboard.
The other option I can think of is to remove the fretboard and replace the old truss rod with a new one but again, I'd imagine that the binding would complicate this quite a bit...
I was wondering whether anyone could offer any suggestions or advice – it would be much appreciated!
If it were mine, I think I would want a working truss rod. You have already indicated that you need it to work so you can correct the relief. With that in mind, and the knowledge that the fingerboard already appears to have been removed, I think I would remove it again and fix the truss rod. You may be able to deal with the warp ( if there is one once the rod is repaired) by clamping the neck into a flat position and then gluing the fingerboard back on.
Perhaps see it you can get the truss rod nut off and buy a replacement, that may be all the rod needs.
Thanks for the replies! Jeff - I tried removing the nut but it is stuck fast, it won't budge, even with heat from a soldering iron.
Removing the fingerboard seems like a good option - would a clothes iron placed on the frets provide enough heat to soften the glue or would it be necessary to remove the frets first?
I've never had much luck with the clothes iron method, I'd leave the frets in, and then remove it with a heat gun. I have one with adjustable temp., they're not expensive. ('Bout 20 bucks?) I'd set it at around 200°C and then work my way from the tongue to the nut. Once that's off, you can see what's to be done with the truss rod. In the photos it looks like the truss rod nut has been glued with epoxy: If that is indeed the case I wouldn't waste a lot of time trying to clean it up, I'd just replace it with a new one, you can get decent ones for under 10 bucks. Maybe pay a bit more for a double-acting one, a great help for problems in the future. With a working truss rod and the fretboard glued back on, you should be able to get the neck adjusted properly.
Thanks Grahame... It's looking like it'll need a new truss rod then. Am I right in thinking the plastic binding is unlikely to come off intact, so I'll just have to cater for that and buy a replacement to glue on before I put the fretboard back?
Yup, the binding is glued to the fretboard and the neck, so remove it before you attempt to separate the glue joint between neck and 'board. Not really worth trying to save it anyway, binding material and the plastic rod you'll need for the side dots cost pennies. You'll almost certainly have to re fret after the fretboard is glued back on, as the frets hang over the binding. Not a bad idea anyway, then you can plane the board properly flat after you've glued it back on. After you've glued the fretboard back on, do the binding first, then the side dots, and then get the fretboard as flat as you can adjusting new truss rod, and sand any humps off before re fretting, sand a bit of "drop off" in between the 14th fret and the sound hole, and then re fret. A new bone nut, and then you're good to go!
Thanks a lot for the info Grahame; I think I'm ready to get started on it now!