Broken headstock--gorilla glue?

[catmandu2]

Considering a headstock broken off at the nut, I would think epoxy. Would Gorilla Glue be viable for this crucial repair?

[Hans]

I don't like Gorilla glue and wouldn't use it for a repair. It just foams too much and is a mess. HHG would be the best joint if it goes together perfectly.

[catmandu2]

Hans, aside from that, is GG capable of bonding sufficiently for such a high stress repair?

BTW, that V6 on your photo album page is simply exquisite. Bravo!

[Hans]

I think I read somewhere that it wasn't too good for apps where there wasn't much glueing surface. I'd probably go for an "industrial strength" epoxy before GG.

[Big Joe]

Gorilla Glue is not good for repairing stringed instruments in any way. Adhesives are a tool and for the job to be right you need the right tools. GG on a stringed instrument is like using a 9 pound sledge hammer to set frets. Right idea. Just wrong tool. Just as the hammer would destroy the mandolin when driving frets, GG could be as devastating to the instrument and would not likely hold.

The mind of repair and adhesive for that break would depend upon the gluing surface and may need extra structural support if it is broken across the grain and straight across. If we have pics we could better tell what may work best.

[catmandu2]

The person who made this repair said that he inserted two steel pins from the neck into the head stock then glued it with gorilla glue and filled the crack with wood filler. He reports that the repair is secure. I'm wondering whether GG is an adequate adhesive in terms of strength and longevity.

Thanks very much for your replies.

[Mario Proulx]

Polyurethane glues are indeed very strong when used in their proper places, but... I have to question -everything- about that repair. Poly glue, steel pins, wood filler, each have no place on a repairman's bench. Much less all 3 in one repair!

[Greg Mirken]

This is not a repair I would trust. It sounds from your last post that this is not your instrument, and you are inquiring about the security of the repair. If you are considering buying this instrument, I'd pass.

[catmandu2]

Actually, I was thinking of trading for it, but decided to pass anyway. Thanks for everyone's input.

[Hans]

What, no wood filler?!?! Pass the bondo!

[barney 59]

I've used polyurethane glues for years and for certain things it is really the only thing.(wet wood jointery). It is messy that's for sure. I had been argueing for a while with people I work with and sometimes for (architects and engineers who were specifying it) that I believed that "Gorilla" glue made for weak joints. Finally a couple of years ago Fine Woodworking commissioned a glue/woodjoint test. The testing was done by Case Western Reserve's wood science lab, which was a big step up for FWW. The results were that polyurethane glue joints were the weakest by far of all other glues tested. Interestingly, liquid hide glue which gets trashed here on the forum out performed polyurethane glue in a straight up gluejoint stress test. Regular Elmer's white glue did nearly as good as Titebond 111 and I'm back to using it more myself,.. weather permitting..

[Mario Proulx]

Again. <sigh> That test was flawed in that the joints were rough machined M&T and not clamped. Having used poly glues, you -know- how the foaming wants to push the joint apart and requires good, even clamping, otherwise, you have no wood-to wood contact, only a foam-filled gap.

Great test if all you do is M&T furniture, but for luthiers, it's of no use, and makes for dangerous thinking. Repeat after me: woodworking is not lutherie, lutherie is not woodworking. Different "needs" altogether.

[swampy]

I love GG, and I would never use it to repair a string instrument, or really for much woodworking. And on a side note, when I was working in a fine cabinet shop years ago, we used Bondo in any instance where the repair was not visible or would be painted, wood filler seemed to flake off or not adhere as well. Not saying I'd use Bondo on an instrument, just that I'm impressed with its role in woodworking.

[woodwizard]

I can see the sign now. "Cars & Guitars Body Shop"

[Dan Hoover]

ok,i'm curious .how well does Bondo,or other resin filler's work on wood?? i use to be involved in a auto restoration biz..i have worked with wood on cars,old cars,some Ford T's,1911 caddilac,Fiat,a couple woody's.....a couple..anything major that couldn't be replaced w/new lumber,like deep gouges,we always used sawdust and elmers..then finished with a glazing putty but over a primer surface..then it would be painted.... i've done some things that i wouldn't do on a running car..with bondo,just for piece's that hang on a wall...pedal cars and such..but how does that really hold up on a working mando?? like i say...i'z just curious...

[Bill Snyder]

ok,i'm curious .how well does Bondo,or other resin filler's work on wood?? ...

I would NEVER use it on an instrument, but on painted posts or columns it works great. It is cheap, fast, easy to work with and ten years later can not be spotted. BTW these are just to fill blemishes (knots, etc.) in the wood and not structural patches.

[mandroid]

Those 'New Yankee Workshop' shows on TV, have the reinforcing with a 'Biscuit' come to mind .

a wood veneer and carbon-fiber one perhaps?

[barney 59]

Again. <sigh> That test was flawed in that the joints were rough machined M&T and not clamped. Having used poly glues, you -know- how the foaming wants to push the joint apart and requires good, even clamping, otherwise, you have no wood-to wood contact, only a foam-filled gap.

Great test if all you do is M&T furniture, but for luthiers, it's of no use, and makes for dangerous thinking. Repeat after me: woodworking is not lutherie, lutherie is not woodworking. Different "needs" altogether.

As I remember the test there were a series of joints from snug tight to sloppy loose and this done with a variety of different materials. The mortise and tenons were not clamped on the joint but the boards were clamped flat in place so that they couldn't move. I don't remember <sigh>advocating for polyurethane glues for instrument work of any kind. I think what I was saying is that I find it to be an inferior glue( to another appropriate glue) in almost any application except in the case of having to work with uncured or wet wood. I think that people use polyurethane glues because they believe they are getting a SUPERIOR bond and I don't believe they are except in the above stated case. I didn't need to learn this from FWW. I had already figured it out from my own experiance. Gorilla,in particular, seems to be very good at marketing. The test results from FWW if flawed would have been flawed across the board -so to speak. Lutherie may be more than woodworking ,and I agree with that, but the working with wood part of it is still just like woodworking.
On another note "Bondo" makes a woodfiller. It isn't pink when mixed,nor is the color of any wood that I know but it is just plain bondo all in all. I have used it but prefer epoxies as a paint grade filler. I do think though you only get to work with epoxy for a limited amount of time before it KILLS you!
I get old instruments to R and R and more than sometimes discover that there have been attempted repairs prior to me getting them. Quick set epoxies seem to be quite popular and I have on occasion found bondo used to replace missing wood (like on a chipped neck). Sometimes these horrible repairs were skillfully done. On solid body electrics it actually might be pretty appropriate.

[Paul Hostetter]

The person who made this repair said that he inserted two steel pins from the neck into the head stock then glued it with gorilla glue and filled the crack with wood filler. He reports that the repair is secure. I'm wondering whether GG is an adequate adhesive in terms of strength and longevity.

Pins are a complete NO. Gorilla Glue is also a complete NO. How many times are you going to ask this question and get the same answer and not comprehend it? The fact that someone did such an inexcusably stupid repair and it has not blown up yet is not an indication of success. This is reminiscent of those largely brainless "It worked for me" pieces that Frets magazine used to run.

[Hans]

Those 'New Yankee Workshop' shows on TV, have the reinforcing with a 'Biscuit' come to mind .

Oh, yea, and lots of nailgun!

[fishtownmike]

epoxy like system 3. Gorilla glue and other polys foam to much and are sloppy and hard to clean with out ruining the finish.

[Larry Howe]

This question touches a nerve for me because I broke the headstock off my F-4 Schneider about 3 weeks ago. My solution was to send it to Bob for a new neck. I used polyurethane glue on a sailboat I built, and I can't imagine using it for an instrument. Even if the joint held, it would be pretty ugly.

--LH

[catmandu2]

Pins are a complete NO. Gorilla Glue is also a complete NO. How many times are you going to ask this question and get the same answer and not comprehend it? The fact that someone did such an inexcusably stupid repair and it has not blown up yet is not an indication of success. This is reminiscent of those largely brainless "It worked for me" pieces that Frets magazine used to run.

Um...yeah. I've only asked it once, and...I think I've got it (about a week ago, actually...).

[Gail Hester]

Um...yeah. I've only asked it once, and...I think I've got it (about a week ago, actually...).

I decided not to pile on about a week ago. At least you got lots of responses to the question and it sparked a good discussion, albeit slightly at your expense.

[catmandu2]

I decided not to pile on about a week ago. At least you got lots of responses to the question and it sparked a good discussion, albeit slightly at your expense.

No problems--I found the responses quite helpful (but I stopped reading this thread after my post on the 23rd...when I said I'd passed on the instrument...then noticed it was still being discussed today.

But having perused back over this thread, and seeing that my last bit of information I offered was in response to Big Joe's suggestion that I provide more detail, I must say that Mr. Hostetter seems a bit tightly wound , who managed to impune the level of intelligence of given mandolin aficionados not once but thrice in his four sentence paragraph. That takes some deftness ..

Mr. Hostetter, you might notice that after I'd thanked everyone for their input, you saw fit to offer your tirade some nine hours later. What's up with that?

Pins are a complete NO. Gorilla Glue is also a complete NO. How many times are you going to ask this question and get the same answer and not comprehend it? The fact that someone did such an inexcusably stupid repair and it has not blown up yet is not an indication of success. This is reminiscent of those largely brainless "It worked for me" pieces that Frets magazine used to run.