Official Luthiers Forum!

Hello all,


Just started a new build with some osage I've had for awhile. I originally thicknesed the back to .085. At that point it still seemed stiff but I went ahead and braced it anyway. The specs on the back; 19" long, 14 1/4" lower bout , ladder braced: top two braces 5/16 x9/16 H, bottom two 3/8 x 9/16 H all brace are euro spruce tappering to about 3/32 at the rim. Tapper starts about 2 5/8 from the rim. 3/4 cross grain spruce center seam brace. Just wondering what your suggestions may be to losen the back up. ie thin the plate, brace maybe both?

thanks
Brent

It really depends on your goals. Personally I like my backs to be resonant (thin), I probably would have thinned it further to around .070". However, on average, 1/4" upper braces are more than sufficient for a 00 size, lower bout braces are a matter of choice, but I would lower the height since they're thicker. You will not compensate for too thick a back (if your goal is a thin/active back) by shaving the braces BTW.
It is not too hard to take the braces off, and re-do it.

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Laurent Brondel
West Paris, Maine - USA
http://www.laurentbrondel.com/

Thanks Laurent,

I thought about removing the braces and thining more. I dont know if it would be worth trying to thin the back with the braces still on? I was thining by hand
with sand paper ( I got it close with a safety planer on the drill press before joining). this osage is some tough stuff. I'll take the plate down more and go from there. By the way Is .070 pretty standard for your backs regardless of wood?


Brent

Brent, how you do it is your choice. However, with braces and a radius on the back it is difficult to do a good job. Sandpaper sounds like a bad idea: you should try a scraper. It makes a quick job of removing Wagner marks and thinning a few thous.
My backs go from about .060" to .115" depending on the wood and guitar size.
Disclaimer: I don't know how thin you should get that piece of osage, there is a point where the wood becomes just flexible and resonant enough, don't get past it.

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Laurent Brondel
West Paris, Maine - USA
http://www.laurentbrondel.com/

Wow, I need to take a look at my back thickness as well. I usually thickness them to .0115-0.125, feeling that a strong back plate might help push the sound forward to the top plate again, but perhaps I need to try a more responsive and thinner back on my next OM. I'm working on three Bubinga/Spruce OM's now, and I think I'm going to incorporate a thinner back plate as well as my new thinner and more delicately braced tops.

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http://www.sixgunguitars.com