luthiers: hide glue?

ive had to do some repair work on an acoustic guitar that requires "glueing" a neck heel to the body. this is being done to correct an eighth inch gap to the body which is causing higher action from the 7th fret up.

ive used hide glue to try to adhere the two together... but, its not holding when i restring it and tune up to concert pitch. due to the tension, it is pulling apart, again. if it would hold, and it usually does for a half hour or so, it would correct the problem. i thought about screwing it together, but it is a nice guitar and i dont want to go "THAT" route.

should i be using hide glue (i know it has a lower melting point and can be reversed if necessary) or something else that would be a stronger bound?

thanks!

rand z

You need to remove the neck and reset the joint.
You can't use hide glue in that way.
Almost any glue would fail.
You need to Reset the neck in the normal manner.
Shim the dovetail, if its a dovetail joint,( it may not be) and glue in the normal manner.
Good luck.

Pics would help a lot. If you're really talking about gluing the heel itself to the body - won't work. There is a lot of force here and requires some sort of mechanical attachment means. Historically this meant a dovetail joint, but there are several mechanical fastening means (bolts) that can be accessed from inside the body. Really need some pics to have a clue what you're really looking at, though.

Better yet, particularly if it is a "nice" guitar as you say, I recommend finding a local repair man. Depends on how brave/skilled you are and how much risk you're willing to take.

That joint needs to be shaped in such a way that you barely need glue to hold it together.

yeah, i know the neck should be reset, but i was trying to stay away from a $400 repair bill.

thanks all!

rand z

Try this for neck reseting !
http://frets.com/FRETSPages/Luthier/Technique/Guitar/NeckReset/00045Reset/00045reset1.html

Try this for neck reseting !
http://frets.com/FRETSPages/Luthier/Technique/Guitar/NeckReset/00045Reset/00045reset1.html


WOW !!!! that's a lot of work....:shock:

I agree with what everyone here is writing. It's good info.

Guitars that do not have a mechanical joint between the neck and the body will fail. Even guitars that have a butt joint at that location usually have a bolt-on neck. I've got guitars with both dovetail joints and mortise & tenon joints. The M & T joint has a pair of bolts in the neck block to keep the neck attached. The M & T are used to keep the joint from sliding around.

I had a Kingston 12 string as a kid. The neck was held on by a pair of inch long wood dowels and a lot of glue. Needless to say, the guitar imploded.

Just a tangential point to make...

Hot hide glue is great for guitars because it sets harder than most other wood glues. Lots of folks think it enhances the tone of a guitar. But it's not stronger than more modern glues.

Daniel

My understanding is that hide glue is a somewhat impure form of gelatine, and therefore has relatively limited strength compared to more modern adhesives, but it has the great advantage that with judicious heating the glued joints can be separated, re-worked and re-glued.

Luthiers use various adhesives for very good reasons, mostly because in the course of its life an instrument will quite likely require partial disassemble, re-working and re-gluing, be it just a pickguard separating from the top, or a complete neck re-set. (The bane of luthiers are home-brew guitar-techs who use epoxy to glue joints together. This can make a further repair almost impossible.)

A neck-joint using a dovetail uses the very close fit of each part to achieve strength, and a minimal amount of glue merely to hold the two set pieces in place. Trying to use glue itself as a main structural component is just asking glue to do something it was never intended to do.

Not quite on topic, and we've already agreed that this joint is not the place to rely on ANY glue, but I use hide for the bulk of my acoustic guitar work. Particularly when dealing with the soundbox - bracing, plate joining, bridges, etc. I would definitely not say hide glue is weaker than other glues - if anything just the opposite. That doesn't particularly make the other glues inferior - if a broken test joint results in wood failure, then the glue joint is stronger than the wood and that's all you can ask. The benefits of hide are many, to me, a few of which are mentioned in the above post. Hide glue actually works by a completely different type of action than, say, AR glues. As a result, rub joints are often used with no clamping action whatsoever. As the joint dries, the pieces are actually drawn into each other creating a very strong, tight joint. And it dries crystal hard - which many will argue is good for tone, as well. In theory, it's certainly believable that it would improve tone due to its crystalline nature, but it's not particularly measurable. In short, I love the stuff!