WRC Top Thickness

[charles Tauber]

Originally Posted by RHayes

My thought is to brace stiffer for the cedar but with zero experience in guitar building, any comments are appreciated.

I don't know how relatively stiff that particular piece of cedar is, but, were it my guitar, I'd brace it much lighter than what you currently have, particularly for such a small guitar (00).

Specifically, I'd make the braces on each side of the sound hole between 1/4 and 3/8" tall. I'd make the side braces about half as tall as you have them. I'd taper the lower bout braces from about 1/2" tall to about half of what you have them as they approach the sides of the guitar, then scalloped to nothing. I'd make the X braces 1/2" to 5/8" tall at the tallest. (I'd scallop the braces as well, but that's a personal preference based on what you are after.)

Although old Martin 00's were spruce or mahogany tops, they were braced shockingly lightly. My first guitar made in my own shop was a cedar-topped copy of a Martin 00-21 from the 30's. Those who have played it are surprised by how loud it is. Now nearly 40 years old, the top shows no sign of being under-braced. (I only make small guitars - steel string and classical - that are classical sized.)

[redir]

I see it the way Charles said as well. You have a small guitar with straight braces and they look a bit heavy. I personally like scalloped on small guitars but there's nothing wrong with straight if that is the sound you are after but keep in mind a small guitar usually has less bass response and make ght benefit from scalloped braces.

[Alan Carruth]

I'm a fan of 'tapered' braces, which tend to work well for 'fingerstyle'. I'd also be likely to remove a fair amount of material from those as shown.

Several years ago Evan Davis published a paper on brace profiles based on a computer model. Evan wrote his PhD thesis on guitar acoustics, and has had a career in noise control with Boeing while building guitars and other stuff on the side. He found that tapering the braces at the edge was not as effective in enhancing the bass as scalloping. Making the top more flexible in the center moves more air than reducing edge stiffness. Of course, you have to watch the structural aspects.

[Howard Klepper]

My thinking about working with red cedar is to make the top about 10% thicker than with spruce (other things about the size and purpose of the guitar being equal) and then brace the same as with spruce.

As everyone else has said, you are overbracing. Cut all of them down (except the UTB). Extend the tapers at the ends a lot further, and bring them down close to the top a lot further from their ends. Taking wood off the sides of the braces improves their stiffness to weight ratio, so do that generously.

I would only disagree with Charles about the soundhole braces. It is not a very active area of the top, and there is a big opening with a concentration of stress around it. I think the traditional Martin style of low soundhole braces is underbuilt. But you could take them down a little. The UTB looks fine as it is, but the wide "popsicle stick' above it can be tapered more at its ends.

The reason to taper close to the top at the end of any brace is so that the brace can flex if there is a blow to the guitar at that spot, rather than breaking free of the top. That's also the reason for the older style of tucking diagonals and finger braces under the X--it does nothing for the "flow" of vibration as some believe. Because the end of each brace comes up to a major stiffener (the rim or another brace) there is no structural problem with the brace being very flexible close to its end in the lower bout. And sound benefits from having compliance near the rim in the lower bout (while the upper bout is more about structural strength, and less about sound, so you leave more wood at the brace ends and tuck into the liners).

I can see that you are a skilled woodworker. Nice work so far.

[RHayes]

Thanks for sharing those thoughts. Makes sense. Went over everything (was excellent practice) and probably didn't take it down as much as I could have but it is Engleman spruce, not Sitka. Probably will find out that isn't good for bracing but this project is about the process for me. I think it was Charles that described me in another thread, I should have picked an established plan and method for a first guitar and make changes down the road if so desired. My guide so far has been an old copy of Cumpiano's book, the internet, and an 8-1/2 x 11 plan view of a 1940 Gibson 00. Of course I'm optimistic that something will rub off on me from viewing the custom build threads here on AGF !!

[RHayes]

My WRC is closed now so presently acquiring a few parts, tools, and figuring out my next steps. Really enjoying the learning process so many thanks for the help here.

[RHayes]

My "all day" neck joint. Future ones, which I hope there will be, should go much quicker.