back brace count

[peter havriluk]

It seems customary to use four braces on a back. Discussions as to dimensions, but the count seems to be four by consensus. If narrower braces were used, same height, and more of them, like for the sake of discussion, seven, could the back be sanded on the thin side, and yet afford rigidity to sand without thinning the back unevenly? Anybody ever done it and described it?

Just wondering.

[ken cierp]

Gibson uses tall 1/4" braces, Martin two tall 5/16" and two 3/8" tall x 3/4" wide. My view is unless you create some kind of lattice arrangement a bunch of short braces is not going to get it, even then I believe it will be problematic. --- operative word is "tall" -- So a higher count of thinner tall braces should kept the back from collapsing. But, what would be the point? Backs on most instruments are about .09 to .105 or so why thinner?

[peter havriluk]

I think my curiosity centered on weight reduction - - - if there was any theoretical merit to the idea of using a thinner back if it was supported well enough to tolerate finishing pressures during sanding. And I for sure don't have the ability to address the topic except in curiosity.

[Tim Benware]

I think my curiosity centered on weight reduction - - - if there was any theoretical merit to the idea of using a thinner back if it was supported well enough to tolerate finishing pressures during sanding. And I for sure don't have the ability to address the topic except in curiosity.

Adding extra braces would increase the overall weight not decrease it.

[peter havriluk]

Tim, you're certainly right if the idea was to add more braces of the same dimension wood as would be used if four braces supported the back. I think the weight of braces would not need to change if the same amount of wood was used, just distributed among more and thinner pieces. (4 pieces 4 units wide = 16 units of width, 8 pieces 2 units wide still equals 16 units of width). I'm curious whether the answer to my mutterings is closer to 'why bother' than 'can't hurt'. I'm sure that in a production environment keeping the parts count down is a dandy idea. But if we're not in a production environment, is there any benefit to raising the brace count, using the same amount of wood, in structural terms? I think I was working around the question of why we settled on four back braces being a norm.

Ken, I was trying to address the 'common wisdom' idea that lighter guitars somehow perform better, and was speculating as to whether using more and narrower braces supporting a thinner-but-just-as-stiff back, because of the increased brace population, would do the instrument any good. Taylor sometimes uses no back braces at all, relying on the domed shape of the laminate used for a back.

Again, thanks, folks, for the attention and comments. I am trying to gather some understanding of reasoning behind what we accept as normative on this part of the bracing discussion.

[ken cierp]

I am not necessarily of the opinion that a lighter (in actual total weight ) OM or D size or what ever is going to sound better than its heavier twin. I primarily focus on the overall weight of the soundboard plus bracing relative to responsiveness -- the string set (any given gage) generates a certain amount of energy or you can think of it as horsepower. So to my simple way of thinking. Like an automobile, the lighter ones need less HP to get the same responsiveness. Perhaps a light rim or back reflects better, or is more in phase than a heavy rim -- I do not know.

[peter havriluk]

Thanks, Ken. Hard enough to manage what we know needs managing, much less wander off in speculation on topics whose parameters we don't know.