When a Loosened Truss Rod Gives No Relief to an old RGX

[guitared]

I have an old (1990 or thereabouts) Taiwan made Yamaha RGX 112P. It's not expensive, but it's really comfortable to play, aside from one thing. . . Despite the truss rod being totally slackened off (it can be tightened and used to add backbow to the neck) the neck has a very slight backbow to it. I've tried putting on heavy strings and tuning higher than standard E, but no cigar. I'd be open to getting a replacement neck for it, but not sure where I could get one to fit the neck pocket - it's more tele-like in shape, but not sure how the dimensions compare. 

TIA! 
 

[thetragichero]

sounds like you need to setup a heat+clamp setup to add a little bow into the neck

[guitared]

Thanks! I have a couple of clamps. I have three questions

1. I can't find any reference to how much I should shim the middle by (and roughly how far either side the middle of the neck I should go with the shimming).
2. Unsurprisingly I don't have the right tool for it, but if I clamp it, and leave it for a few hours on top of a warm radiator, should that help with it.
3. Lastly, would some extra humidity help make the wood more "pliable" given how old it is?

Nov 4, 2022 8:27:16 GMT -5 thetragichero said:

sounds like you need to setup a heat+clamp setup to add a little bow into the neck

[cynical1]

Nov 4, 2022 9:50:19 GMT -5 guitared said:

...I have three questions

1. I can't find any reference to how much I should shim the middle by (and roughly how far either side the middle of the neck I should go with the shimming).

Start here: guitarnuts2.proboards.com/post/103019/thread

Feel free to ask questions on this. There are also a load of videos on this topic on YouTube, as well as luthier sites. This is the most important part of the guitar...go slow...learn all you can. Work in smaller steps giving the neck time to adjust. If it takes a few tries, so be it. It's a lot better than the truss rod popping out of the fingerboard. Don't ask me how I know that...

2. Unsurprisingly I don't have the right tool for it, but if I clamp it, and leave it for a few hours on top of a warm radiator, should that help with it.

This depends entirely on how bad the bow is.  Where is it playable and unplayable?  Typically the heating is done just prior to trying to move the neck.  Again, look for "fix backbow" on YouTube.  It doesn't take an arsenal of tools.  Patience is the most useful one.

3. Lastly, would some extra humidity help make the wood more "pliable" given how old it is?

Considering the age of your guitar, leaving it in a humid location will not effect much.  It could also have a detrimental effect.  The heat and tension applied slowly and precisely does work.

HTC1