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I guess it was bound to happen to me sometime. Potato chip back (top not on).

I don't usually work with maple. Yes, shop is conditioned and very well insulated. But that does not mean it did not dry out. Ordering a hygrometer. Prefer a recommendation.

So I bagged it with a wet sponge on a plate. Put on go-bar deck with radius dish and pressed it down. That about right? Let it sit a couple of days?

Concern, it could happen after I close the box?

Mike

Edit: Probably should get a humidifier... thoughts?

Pics? Was it braced? Glued to the rim? Just center lined glued? Or just the 2 back halves?

Oh, by top not on you must mean the back is glued to the rim, sorry I didn't catch that.

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Brian R, Wood Mechanic
N8ZED

yes, back is glued to rim. Its a complete box except for the top going on. It was fine yesterday.

Hey Mike, just got in from plowing snow on the shore of Lake Superior so you can guess dealing with humidity swings is built in to my locale.

I was kinda hoping someone else would chime in.

My opinion is you are going to have to take the back off, remove the braces, let everything acclimate to a lower RH and do it over. Otherwise it will happen again till remedied.

Maple, especially figured is often flat sawn because it can show more figure but that could be a contributor if that's the case because the shrink swell across grain is greater in non-quartered wood.

2 things I don't do except in low humidity is brace and assemble the box.

I believe the worst things that happen to guitars happen far more frequently during the shrinking season and especially when built in higher RH.

When built in lower RH the structure is less stressed in that climate and under compression in higher RH. Cracks, dome collapse, frets sticking out and a host of other things occur when an instrument built in higher RH goes into a drier environment.

I don't believe any instrument is going to be kept in a perfectly humidified environment for its life unless it is built and stays forever in the desert or rain forest. Expecting owners to religiously maintain instruments in a perfect environment is a stretch to me.

I like bracing and box assembly to happen around 30-35%. I expect to get some hate mail but it works for me.

I'd love to hear other solutions but don't think keeping a wet sponge in the case for eternity is realistic.

It would be a lot worse if the top was on and the rest.

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Brian R, Wood Mechanic
N8ZED

I had the exact same thoughts.

Probably caused by the hysteresis effect I'm always harping on. Even if the shop is kept at constant RH, the condition of the wood is different depending on whether it acclimated from wet down to the control level or dry up to the control level. I recommend always drying below the control level and acclimating up.

If it fails, I’m gonna yank the braces. Confident I can do that. Thanks!