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I got on my bench one of those "cheap" (compared to custom/high end guitars, around 1000 dollars) Martin 000. The back has somehow separated from the side in the upper bout in that area. The guitar is brand new, however the customer bought it online from a store in the US, had it shipped to Taiwan. The store wants to help but he would have to mail the guitar back, probably costing 200 dollars or so to do it. I charged him half that to get it fixed.

The question is, how could this possibly happen? The back is separated from the side and the side has moved inward a little bit. I don't know if it was glue failure or someone pushed it out. What kind of glue does Martin use?

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Cat-gut strings are made from kitten guts, stretched out to near breaking point and then hardened with grue saliva. As a result these give a feeling of Pain and anguish whenever played, and often end up playing themselves backwards as part of satanic rituals.

Typhoon Guitars
http://www.typhoon-guitars.com

sounds like expansion from being introduced to a humid environment...i wouldn't blame the glue, rather than the joint prep- poor fitting, sounds like.

You sure? It sure doesn't look like it... it feels almost like it was forced out from the inside or someone hit it in the wrong way. I'm not seeing any sign of exposure to extreme humidity...

How much humidity does it take for a guitar to become damaged? I heard too low of a humidity is much worse than too high.

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Cat-gut strings are made from kitten guts, stretched out to near breaking point and then hardened with grue saliva. As a result these give a feeling of Pain and anguish whenever played, and often end up playing themselves backwards as part of satanic rituals.

Typhoon Guitars
http://www.typhoon-guitars.com

If the joint was compromised in some way via contamination or another factor during construction a slight impact could have caused this on an unbound guitar. The bindings are not just decoration, they serve the purpose of protecting and reinforcing the joints of the plates to the rims. Once the joint pops the rim will move in whatever direction the stress dictates, this is one of the drawbacks to forcing rims to conform to molds during construction, it induces stress into the joint to start with. If the joint is weak and already under duress it will not take a lot to make it fail completely. The changes in RH during shipping may have been enough extra stress to cause failure as well. If it was new it should have been covered by Martin's Factory warranty, though I don't know what that would mean where you are.

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Brian

You never know what you are capable of until you actually try.

https://www.howardguitarsdelaware.com/

I think Martin uses plain old Titebond.

Kevin Looker

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I'm not a luthier.
I'm just a guy who builds guitars in his basement.
It's better than playing golf.

Probably a bad glue joint or it got bumped in shipping. Maybe some of both.
Can you push the side out from the inside? I'd guess the bend relaxed once it was free of the mold and glue joint. Re-gluing should work fine. Put a knife blade in the crack and pry GENTLY to see if more of the joint is bad.

I pushed it out as much as I could but I couldn't push it anymore past a certain point... so now there's a tiny (maybe .003"?) lip that I'll have to sand off and touch up to hide it.

_________________
Cat-gut strings are made from kitten guts, stretched out to near breaking point and then hardened with grue saliva. As a result these give a feeling of Pain and anguish whenever played, and often end up playing themselves backwards as part of satanic rituals.

Typhoon Guitars
http://www.typhoon-guitars.com

I saw that on some of the bottom of the barrel Martins and Taylors...

Upon closer inspection - it looked like they were painting the components - THEN gluing them together... and got some overspray on the glue areas.... and tried to glue them anyway.... At least, that's the only way I could figure out how they got paint INSIDE the glue joints like that....

If you look at them wrong - *Ker-poink*

about 1/4" below the top, beneath the separation, center of picture, is that an ouchie I'm seeing?