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Hi, Ive made a D28 using a Blues Creek kit which came with forward shifted scalloped soundboard braces, which were 5/16 x 5/8 max and it sounds great.

I’m now making a rosewood/spruce Gibson J45 from scratch, using Michael Collins plans based on a 1957 model. They show unscalloped soundboard braces which are 1/4 x 33/64 max. The J45 body is roughly the same size as the D28.

My question is - will I achieve stability and a bigger, deeper sound with the 1/4 unscalloped, or the 5/16 scalloped braces? I’m hoping to use light strings .054 - .012 or at the most .055 - .0125

Thanks very much, David Snowdon

I own a 53 J 50 same guitar but in natural
with Gibson the braces were all over the place. Not sure what his plan is like . While the shape is different I don't think it is that much and the 1/4 in braces were also used on the Martin D35
In my experience I have seen more issues on 1/4 scallop braced guitars. So you should be fine. The Martin and gibson braces are also shaped a bit different
so enjoy the build and you will no a lot more once you make it.
post pics as you go.

Layman's reaction: By the time the tapering top-to-bottom of the braces and the scalloping on the braces has been performed, I think it hardly matters whether a brace started out 1/4-inch or 5/16-inch wide at the base. The glue line at the base is about the only place where the nominal brace width is present.

tippie53 wrote:I own a 53 J 50 same guitar but in natural
with Gibson the braces were all over the place. Not sure what his plan is like . While the shape is different I don't think it is that much and the 1/4 in braces were also used on the Martin D35
In my experience I have seen more issues on 1/4 scallop braced guitars. So you should be fine. The Martin and gibson braces are also shaped a bit different
so enjoy the build and you will no a lot more once you make it.
post pics as you go.

Thanks John. I’m inclined to follow my J45 drawings and use 1/4” unscalloped braces. Might you know what the D35 1/4” X brace and tone bar heights are, to compare them to my J45 plans?

Thanks, Dave

Structurally, the height of the brace contributes much more to stiffness than does the width.

And that's the reason I haven't used scalloped braces. I think I'm capable of making a scallop just one chisel pass too deep out of total ignorance. With height being so determinant, I avoid finding out whether I did something bad by scalloping too much by not scalloping. Tapering braces in width and height seems to be safer for me and more resistant to overdoing the material removal. Still learning.