Washburn back grew

[John]

I've got a Washburn flattop on my bench. The back is pushing the binding out by an eighth of an inch on the treble side and a little less on the bass side. This is over a three inch area, three inches from either side of the end block. The middle and shoulder back brace are loose. The back is loose from the kerfing. The sides are properly formed all through this area, the only explanation that works is the the back got longer by an eighth at the same place on both sides of the end block. Has anybody seen this before?

[Ned Knepp]

Perhaps the wood was dry when the guitar was built. I know that the rule of thumb is that wood doesn't expand over the length of the grain BUT I've seen this before in other furniture. It's not completely unknown that a particular piece of wood will draw moisture and expand in length. Maybe you've been visited but just such a piece of wood.

[Demetry Merkuloff]

Can you show it?

I think the back has become flatter than it was, that's why it's pushing the bindging. What about the end block, is it loose from the back?

[John]

The end block and lower bout back brace are secure. This is one of the times pictures don't work as well as a good description. The back is bookmatched, I think Neds on the right track.

[George Roberts]

I agree with Ned, that wood is very unlikely to expand in the direction of the grain.  A more likely explanation (to me) is that there has been shrinkage in the rest of the guitar.

[John]

Sorry George but that would be the opposite of what Ned said.

[Andrew]

I agree with George that its very unlikely the back expanded 1/8" along the grain, although its not impossible.. But I think it would be very rare, and its more likely something else happened.

If the sides didnt shrink (but they could have without distorting much if the top compressed with them), then Demetry might be on to something about the back becoming flatter, especially considering there are also back braces loose. Is the guitar stored in a hard shell case, and if so, is the fit very tight? If the guitar was being squeezed just the right way and also experienced a humidity change that MAY explain it, especially if the glue joints were questionable to begin with (it sounds like they might have been, considering that amount of dimensional change and no accompanying cracks).