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rvenneri

Help! Do I Have A Major Problem Or Can This Be Fixed?

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Hi Guys,

After carving braces on front and back I glued the soundboard to the sides. It is glued and has a nice radius on the soundboard.

Now I go to glue the back to the sides and, before gluing I find that the nice radius I had on the back all this time is now gone flat ,even to the point of curving the other way a bit.

Is this a fatal eror or can something be done to get the radius back on the back.

Bob Venneri

Venneris

www.venneris.com

rvenneri@venneris.com

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This problem doesn't make sense to me. In the absence of other posts, maybe some pictures? The braces give the radius to the back, so as long as they're ok, the back should be ok too, right?

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Thanks for the reply I was begining to think I was an out cast as I never seem to get many replies to my post. I am a bamboo fly rod builder and whenever a post is made on rodbuilding sites there are so many replies you get info overload.

I did glue in the arched braces but I believe due to lack of moisture in the cold northeast air the back dried out and began to shrink flatten out, even with arched bracing glued to it.

Thanks again

Bob Venneri

Venneris.com

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Yeah, I looked at your page. You do nice work. Sometimes people won't respond if they don't have anything to say. So if you have arched braces and the back is arching the other way, is it monstrously wavy or what? I still don't understand. And truth be told, there are many others here with a lot more experience than I have. Can you snap a picture on your phone or something? That might get more responses.

EDIT: FYI, I'd also post this over at luthiersforum.com. There are many more dedicated acoustic builders over there.

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I suspect it can be fixed (hard to tell without pics) but I am worried that you had that much movement from drying out. If you had glued it the chanced are it would have cracked.

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Bob: The back has gone concave because of a drop in RH(Relative Humidity). The back plates lost moisture and shrunk. When that happens the plate has to go flat or even concave. When building one has to control RH at about 40% or so. If the braces were glued with RH at 40% and it is now much drier you may be OK. Check your RH now with back concave. If you are at 40% or so, the news is not good. The braces should come off and be re glued at the correct RH. Sorry.

Tom

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