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i have a friends Gibson ES335 with a peghead crack
i did some reading & hide glue seems to be the recommended solution, but i have no experience with it
i have some very good wood glue from Lee Valley (2002 GF) and was wondering if it would be OK in this situation
this is a fresh break & has never been repaired before

mark

here is a link to the PVA Lee Valley glue
http://www.leevalley.com/wood/page.aspx?c=1&p=45104&cat=1,1...

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I have a crack in my soundboard and have been asking questions in another forum. The answers lead me to believe that PVA glue is not so good for fixing cracks. I fixed the crack with LMI's PV instrument maker's glue. I sanded it out and it looked okay, however, the glue failed and the crack is back. The advice I received is to use hot hide glue.

Many years ago, I started an upholstery business. When I got into the shop, I turned on an old iron that was sitting upside down. On that iron, I placed a coffee can of hot hide glue and used it often for gluing joints together. It wasn't hard to keep the glue warm and of the right consistency.

I have purchased some powdered hide glue from WoodCrafters and will use that to fix the crack. I shall make a stop at a second hand shop to see if I can find an old iron.
Did you cleat the back of the crack or reinforce the back of the crack with a cross gain veneer? If not , do so - the soundboard is under tension/loaded in two dimensions and is a 'working' surface. This info good for PVA, hide or epoxy glues. Rusty.
the crack had a lot of surface area and i didn't think anything more than a good glue job was required (at least that is what i was led to believe by looking at other peg head repairs with similar cracks)
can i just inject more glue & do it again, or should i attempt to open it up some more to get more surface area to work with?

mark
Yes, new hot hide glue will remelt the original. I might squirt some hot water through there with a hypodermic first. Make sure your glue is good and you are preparing it right. Proper consistency is very watery, and gravity will help it penetrate. I help it along by squeezing the crack closed and open a few times.
You know, guys, the probable cause of the joint failure was premature gelling of the glue before it was closed up. The peghead wasn't warm enough and the glue gelled before clamp up. Now the problem is, pardon me for saying so, very much worse. The glue that's in the joint now is not well adhered to the wood. It can't be removed to start over and so it has to be recruited by rehydrating it, not as a gel but as a free flowing liquid.

The way to make that happen is with water and heat using a source that is sufficiently large to get THE CRACK up to the right temperature and keep it there for however long it takes to clamp it up. That didn't happen the first time and the glue job failed.

I had a hide glue failure while vacuum gluing a bridge on; the temp in the room was a little to low or I was too slow (more likely). Luckily, I saw the problem immediately and manage to solve it right then and there. What I did was set up the vacuum clamp again and place a big ziplock bag of water at ~150degF into the well and, after about 15min, turned on the vacuum again. Came out just fine and has stayed on. You might want to figure out how to do the same sort of thing with this repair. Have patience and keep the water in the bags that surround the peghead warm by replacing them with freshly heated bags. It will take longer than you would guess to get that peghead up to the right temperature. THEN, when you stuff the joint with new hot hide glue, the whole peghead is going to be at a temperature that will promote reincorporation of the old hide glue in the joint and give you good adhesion. God, I hope this works.

Best of luck,
Bob
I have followed this thread with some concern, not because the advice has been bad, it hasn't been - but because Mark who clearly stated he had no experience with hide glue at all and was an amateur has been thrown into the deep-end regarding a repair to a reasonably valuable instrument. The advice offered after this repair failed is too late and Mark is left with a difficult and costly procedure to fix what was a simple repair. I wouldn't do brain surgery without practicing first and can't see why we should advise budding luthiers/repairmen to attempt the same. Practice on cheap/junk guitars and then test the repair over time...repeat until it sinks in.
Alternatively, use Titebond as we have for ten years of authorised Gibson and other neckbreaks (some monitored and tracked for QA purposes over this period) - it may not be as sexy as hide glue but it is easy to use and works, everywhere, everytime.

If this business was easy everyone would be doing it. Sincerely, Rusty.
You're right on all counts, Rusty. I'm a whizbang at building classical guitars and know enough about repair work to realize it's something I should routinely turn down except for the most rudimentary operations. of which the current example is not one. It's a different discipline with different experience requirements. Period. Every budding repair person should learn how to say "No" instead of "Sure, I'll give that a shot" when confronted with a tough repair on a valuable instrument.

Bob
Thanks guys, Bob has picked up the issue, it's not about what I use or you use or how long we can piss for, it's about bringing along the history and philosophy of how to approach this difficult and diverse job so those that are and those that follow can pick over our collective trade knowledge and work practices to their benefit.

Yep, the next time I say "I'll give it a shot" I deserve to be shot - it's taken me eleven years to say 'no' and I have jobs getting very dusty at the back of the workshop that are result of my lack of discipline. That's all I know. Rusty.
Please don't beat everyone up too much. I'm a big boy and i had a good idea what i was getting into even though i am new at this. I'm disappointed that the repair didn't work, but i learn from my mistakes (altho i prefer to learn from others mistakes)
If it means heating the peg head up and redoing it, then that's what has to be done. I guess there is always a job that doesn't work the first time & for me it was the first one.
I appreciate everyone's advice & hope to continually learn (hopefully not as painfully).

mark
Troubleshooting is an acquired skill and one of the most important lessons is to know when you are in over your head. Another important lesson is that it's very hard to progress if you don't, sometimes, go in over your head. Not trying would have kept you out of this position but it almost certainly would have kept you from growing too. Sometimes you just have to give it a shot.

Ned
I think the biggest problem people that have little experience with hide glue do, is not have the glue thin enough. With thin glue it is easier to get it to flow completely into the joint and it won't set up as fast. When I say thin, I mean like water, but yet is slippery when felt between your thumb and finger. I use that kind of solution for any glue job I do, even a bridge glued on will hold up fine.
Besides having thin glue you need to warm the parts well.
I'd use Greg Merken's advise and run some hot water into the joint, that will soften the glue in the joint, then add some more glue and clamp it for 24 hours minimum.

Jim
Bob Webster's comment about premature gelling sounds plausible. I aim a heatlamp at the part from a couple feet away for about 30 minutes until I feel the neck is warm clear through. Not hot, just warm. As Jim said, run some hot water through to soften the glue that's in there, Squish some fresh hot glue in there and clamp.
Unlike some other glues (Titebond II), hide glue is pretty easy to rework in a situation like this.

Greg

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