Induced curve idea?

[Tim Mace]

Has anyone ever tried another brace system such as
thin material heat/bent to desired curvature and glued under the top.I'm going to to try it unless someone already knows it won't work.More of a flat/slat.Maybe use 1/8" ovangkol???I know mando's create a lot of pressure there,
just wondering if it would push the sides out?Surely it would work on the back.

[Doug T]

I would suspect that as the wood returns to it's natural state (which is will over years) it would tend to deform the sides, or actually pull the top down. If you are looking for extra strength, you might consider trying a sandwich of spruce/carbon fiber/spruce and cut that to shape. Anyone here worked with composite sandwiches for bracing???

[Tim Mace]

I'm thinking arch,a little more than typical and ovang is mighty rigid...
Somebody stop me pleeeeaaaase!

[Ned Knepp]

If you are fitting this to a carved top mando, there will be a pretty good twist involved besides the arch. Won't that "bind" the brace so that it will not be as reactive to the vibrations transmitted from the bridge?

Ned

[Tim Mace]

These are flat top mandos and the arch/band will serve as brace.I know I'm pushin the physics but ..just thinking about it if it can withstand the string pressure more sound box volume will be created.Going to try maple underneath mahogany.Already I can see what a great arch effect it has..I hope Doug's prophecy don't come to pass..just experimenting anyway.Think of a shallow treasure chest or turtlelike/less arch.

[Doug T]

Tim,
I wish I could recall the name of the maker who had a "barrel" top for his guitars, but I think that Frank has pics on frets. If I remember correctly, the ribs are actually cut to match that barrel shape, lending a great deal of support, and I'd suspect that the braces are cut to match that. You could cut a "barrel" form rather than a bowl form and do your tops that way. After making my first guitar with a bowl form, I starting putting the neck brace and bridge plate on flat, and then "bowled" in the rest. So, braces match the bowl forms, except for the one by the neck and the plate. I found that I get a much flatter region for neck attachment, and better adhearance of the plate. Don't know if it really relates, but it's about the extent I've experimented with curvatures of the braces (I do make my own patterns).

[Rick Homan]

If you bend a thin piece of wood, perhaps over a curved form, put glue on it, and bend another piece of wood over it and clamp them together, the two will remain curved once the glue has dried, because they cannot slide past each other to straighten out.

I'll be honest and say I have no practical experience of this; but I have heard Charles Fox talk about it as an interesting principle from boat-building for making something light, strong and curved. I hope this is relevant.

[Doug T]

Rick,
I didn't even think of that. Interesting idea, maybe sometime I'll whip out a few braces like this to have sitting around and contemplate. One could sand a from from their bowl form, and then use it in a go deck....
Doug

[Joey Herscovitch]

It sounds very similar to the way curved frame chairs are made (think Ikea). I have a chair like this built by a fellow builder almost 30 years ago. He glued laminations of 1/8" mahogany w/ grain running in same direction & a thin oak veneer top & bottom for finish. The chair is still in use & has seen a lot of weight in that time. The laminations make it very strong & yet resilient (has a springy feel). The 2 bent side rails are unsupported & haven't deformed at all. Also knew someone who glued up the sides on a Baby Grand piano this way. Not sure if it's always done that way.

[Doug T]

Pianos are, as far as I know, always laminated. A friend of the family (who recently passed) built a number of different keyboard instruments, but not pianos (some fortepianos and spinnets, mostly harpsichords) and she said she always built them "Coffin" style. Yeah, those laminated form chairs do last. hmmmm....

[mathieu thomas-guy]

Only concern, wich would be mostly metaphysical I admit, would be to introduce more glue in the instrument. I personally like to stare at my braces, flex them, listen to them, shape then sand them, get the feel out of those little pieces of wood, wich I like to think all can ADD to the final sound. Plywood is a great invention who simply revolutionize wood working but to me never really ADD any sound to a guitar. Just trying to mess you up!! (you asked for it!) From a big Ikea fan who just find this site, really cool 'be back for sure.

[Rick Homan]

Ca va bien, Mathieu! It's a funny thing about laminates in guitars. On the one hand, we think of them being used in cheap, mass market instruments because they are less expensive than tonewoods and more durable, hence less prone to warranty claims. On the other hand, they are used by the the most innovative luthiers creating the next generation of high-performance classical guitars. Also, the original Selmer-Maccaferri guitars had laminate back and sides, a feature largely ignored by buyers of high-end, luthier-made copies. I suppose it's like screw-on aluminum caps for bottles of wine; they function very well but have unfortunate associations.