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I'm in the early stages of a euro maple/spruce 12 fret nick lucas style and am considering cedar instead of spruce back bracing.i have prepared a set of each to the same dimensions, the cedar is significantly heavier and seems a little stiffer so as planning to reduce them a little.

I'm following a plan John Arnold gave me and am considering only tucking the top two braces to allow for more possible movement in the lower bout of the back.

any thoughts or considerations appreciated. Just to note this is build number three for me and I'm not a 'numbers and formulae' builder at the moment.
Thanks all.

I usually tuck all my back braces, but make the lower bout braces wide and relatively flat to keep them a bit more flexible to allow for changes in relative humidity

I would still tuck the lower braces, but make them a bit lower at the ends. I have cut spruce braces down to around 1/16" tall without any structural issues.
It won't take much reduction in height to reduce the stiffness a lot.....remember that stiffness is proportional to the cube of the height.

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John

Why are you considering a hardwood for your back braces? In the text you are saying cedar, but the subject says Spanish cedar (which is not a cedar). If you want the back to be free to contribute to the sound you would do better with spruce as you get the most stiffness for the mass of the braces. The guitar would smell good! I find it more like mahogany than a true cedar.

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http://www.Harvestmoonguitars.com

Yes, I meant the Spanish cedar which is not a cedar. Thanks for the replies. I just had the sp. Cedar braces hanging around and thought they might add a bit of colour both visually and possibly tonally?

Lots of guitars have been built with Spanish cedar and Mahogany back braces, so carry on, but heed the advice about tucking the ends.
Tom

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A person who has never made a mistake has never made anything!!!

I think it might depend on what type of construction that you are doing.
An "active" back (relatively thicker top, thinner back) would probably benefit from spruce.
A "reflective" back (heavier back thinner more flexible top) would be fine with the Cedar in that it will add a little additional mass which is good.
Since I'm doing a "reflective back" type of construction (classical guitars) I use Spanish cedar for back braces.

I use mahogany braces on all my bouzouki backs. Works great. I have even seen mahogany used for the upper transverse brace on the top with great results.

I also have used Spanish cedar back braces on a classical guitar, Mike in his OP mentioned not tucking the lower back braces to free up the back to move. I assumed he was trying to get an active back not a reflective back.

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http://www.Harvestmoonguitars.com

All of my back braces on my classicals are Spanish Cedar. It's light, stiff, and really smells great. It also happens to go well with the Spanish Cedar back linings I use.

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Waddy

Photobucket Build Album Library

Sound Clips of most of my guitars

it can even make an indian rosewood guitar smell great!

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member of the guild of professional dilettantes

All my back braces are laminated red spruce/BRW with a resonant back, so go ahead and do what you feel make sense. In the end, no one can tell you what will work for you. Follow your own logic and sense.

Going with the Spanish cedar and mahogany back strip.looks great against the maple and I have the materials wanting to be used. I've reduced the width of the braces by around 1 . 5mm to account for the increased weight and stiffness.may I ask why I'm advised to tuck the back bracing?

"may I ask why I'm advised to tuck the back bracing?"

It is structurally stronger and doesn't hurt the performance of the back.

As a repairman, it doesn't take long to realize the virtue of tucked braces. I have reglued hundreds of braces that popped loose on the ends......most of which were not tucked. A little too much pressure on the outside of the guitar (accidentally or otherwise) and the stress is localized at the ends of the larger braces.
To realize the structural advantage, the tucking must be done so that there is no gap between the top of the brace and the kerfing. Leave a gap, and you have defeated the purpose entirely.

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John

John, that is one of the best explanations for the use of tucked braces I have ever read.

Thanks