Concave Soundboard at Bridge on New Build

[Gman53]

Hi, New to this forum. I've only built one guitar and it overall went well. I have a chance to "rescue" a StewMac Kit which has some problems. Apparently the neck needs some work to fix the angle, not a problem. But the top is concave at the area where the bridge would go? It's apparently about 3/16" below the straight edge. This seems strange considering what little I know that the X braces should be doing? Clearly it should be convex here. I live in N. California and we rarely have humidity problems, but this apparently is one? So if I re- humidify, can it be saved or will the braces be bowed, will this constantly be a problem guitar? With the neck fixed and eventually strings put on to exert pull will this guitar ever be "normal?" This would be a cheap way for me to learn to fix a neck angle, do some other new things but I don't want to get to a place where I can never set up the guitar because it keeps reverting to being concave?

[jread]

welcome. I don't know if humidifying them would be enough. If I picked up what you described as-is, I'd humidify the top but if it doesn't go back ten I'd likely remove/replace braces and move on with the the build but others may have more experience. Why start sideways are my thoughts. It's not vintage and they come off.

[phavriluk]

I'm a simpleminded soul, and I've tried to keep things simple: Don't do a subsequent step if a prior one is wrong.

My opinions:

I'm offering a guess out of ignorance: Let the guitar acclimate to its environment, and if the soundboard doesn't resolve itself, I'd think about removing and rebracing the soundboard. Playing games with humidity will never be right and the project becomes useless as an instrument. Get the soundboard correct before proceeding; any effort spent now will be trivial compared to all the dancing that will attend to ignoring a problem. There might turn out to be some bracing problems underlying this concave soundboard.

And same for the back.

Was this kit assembled in a climate different from the one it's now living in?

[Gman53]

Peter, This was a StewMac Kit put together in N. California where I live. The top issue was just discovered when the cut out was done for the neck and a straight edge was put across where he bridge would sit after an initial neck angle check was high. The humidity was uncontrolled but always in the 40-50% range when noted (cement floor garage under a huge tree essentially). Other unbraced hanging soundboards apparently are at most 1/8" bowed at the bridge area so it seemed strange that the X braces did nothing. Sounds like it's better to just let this alone.

[MaineGeezer]

It doesn't sound as though it's going to be a workable guitar the way it is. Assuming you can get it cheap (free?), it would be a good way to to get some repair experience. I'd be inclined to stick a USB camera through the sound hole and try to figure out what is going on with the bracing, then proceed from there.

[carld05]

If the box is already closed, maybe removing the back to replace the top bracing would fix that concave problem. Do you have a gobar deck and concave forms (25' or 28' radius) to do that? I think that needs to be done before addressing the neck angle.

[Gman53]

Thanks, I've decided to just move on and let this one go. Take care.