Official Luthiers Forum!

Well, after 10 guitars I have a guitar with a crack in the back....I know how it happened..Low RH..The wood is Flamed Maple and the guitar was my best piece of work so far...I have the Humidity back up to 40 in the basement room....It closed a little...I've now decided to try and get the humidity up a lot more and see what happens...Any suggestions on how i should approach this....I used a clamp across the upper bout but it didn't seem to make a difference..Any help will be greatly appreciated. Larry

try putting it in a case with an in-case humidifier. Either a homemade one or a storebought will work. It may take a few days/weeks to close up but it should help. then a wide clamp across the upper part of the back like you already tried. At that point you can either drop in thin CA or try hot hide glue. I like HHG for this sometimes as it may pull it together a little more as it dries. And it cleans up nicely. Otherwise the CA should work and you'll just have to touch it up.

Haven't had one quite that bad but recently some figured mahogany gave me a fit right on the grain line and followed the quilted grain and I believe RH was probably the culprit even though I'm judicious with it. Happened as summer left and cool weather arrived. Good luck and maybe some others have had more experience with this particular area of the guitar and be of more help.

SR

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"We might not be big but we sure are slow"

My friend John Greven hangs them up in the bathroom with the shower running until they close, then wick in some CA.
-C

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Freeborn Guitars
and home of BeauGuard©

Yep, more humidity. I wouldn't do the shower thing, but you do need to get it up to the 80+% range for several hours. 90+% if that hasn't closed it. Then I would use CA. Hide is good, but then keep the humidity up while it cures overnight. Cleat the crack after your glue is set.

Your maple was mostly flatsawn, which contributed a lot to it cracking. I'd suggest getting cleats under the bookmatched area on the other side; it can easily do the same thing.

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Howard Klepper
http://www.klepperguitars.com

When all else fails, clean the shop.

I usually put the guitar in a large clear or blue type plastic bag with a damp sponge or two in the bag. Seal the bag with a twist tie and you should see the crack close within a day or two, then do what Howard suggested.

Cal

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Remember, there are no stupid questions, only stupid answers!

I've got no help to add, but: I feel your pain.

Howard ...
This is the first time using the Maple...I have been using EIR and Mahogany....Should I have done my homework first and checked out flat sawn and quarter sawn maple before I jumped at what looked like a good deal? From what I gather from you comment you don't have a high regard for flat sawn woods..I would like your thouhts on this(or any body for that matter)..I am seriously thinking about ordering a new back and replacing it.....Thanks for your interest...Larry

I do the shower thing too. I'll take a shower and then put the guitar in there for a few hours and take it to it's case. You don't want beads of water on it but it's a great way to humidify quickly from my experience. I like using Titebond for cracks because it's easy to clean up. If you use CA place tape along the crack as close as possible to help with clean up. You can build clamps by tracing the upper bout on a 2 x 4 and bandsawing to the lines. Double stick some cork on the contact surface. When gluing make sure you open the crack up good and can see squeeze out on the inside, clean that up too. Finish up with a few cross grained cleats on the inside and you will be good to go.