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Question for you folks - Anyone using torrefied bracing? In the Luthier on Luthier podcast with Laurent Brondel he mentioned he wouldn't consider using torrefied bracing because it's too brittle. And of course.. the uke sitting on my bench is braced with torrefied spruce from SM.

Do you agree with the assessment of it being too brittle?

Any experience with it, successes or failures?

Do you build differently with it? Make the braces a little taller to add stiffness? A little wider for more glue surface area?

Ok, a few questions I guess.

Thanks!
Brad

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It is in fact brittle, but I've not had a problem so far. It's not going to break under string tension. You need to be really watchful for runout though. I have also stopped using it, mostly because most commercial bracestock is sawn, not split, and therefore runout abounds.

I bought some to go along with some of the torrified tops I purchased as well. So far I've avoided it as I'm a bit to worried about using it.

I've used it successfully and really notice a sound difference. I buy it in billet form and split it to reduce the run out.

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Tim Benware
Creedmoor, NC

Plenty of talk on the internet relative to glue joint failures on thermally modified wood projects in general -- be it protein or PVC adhesives. Might be worth some research?

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Ken Cierp

http://www.kennethmichaelguitars.com/

How long the wood has been baked also matters. Letting the glue (PVC) sit on the surfaces for a minute or two before joining seems to help.

I've re-topped eight guitars so far using torrefied wood for both the tops and brace stock. This includes three using torrefied Adi and five using torrefied Sitka spruce from SM. All were glued using OBG. (center joint & for gluing braces to the top) All are played daily by their owners. None have reported any problems with braces splitting or popping loose.

I haven't noticed any real brittleness, per se, though the wood is more delicate than non-torrefied. I figure it should be treated like I'm working with 300-year-old wood.

The torrefied wood is already stiffer than its non-torrefied counterpart, so if anything I'd be making the braces, either a little narrower, a little shorter or a little of both.

The narrowest torrefied braces I've worked with are about 1/8", glued with OBG. Again, I haven't noticed any problems. On one guitar I had to make doublers to keep the small epaulet holes from breaking out. The doublers were about 1/32" thick (flat-sawn) and worked just fine.

I've built two guitars with torrefied tops and bracing. one is two years old, the other three. A slope dreadnaught, and an OLF small jumbo.
No glue joint problems with either one. The older of the two is still in my possession, and the slope D is in Colorado. Both are great sounding guitars (to my ear, for what that is worth). The aged woods are from Stew Mac. The builder has to be careful of splitting with the tops. Very brittle stuff. Ask me how I know. The last batch of bracing stock I received from S Mac was lousy. No straight grain. You can remove more material from the braces, but, as always it will depend on each piece. As far as the torrefied tops thickness, in general you can thin them more. But that as always will depend on each top. I make all my top and back bracing 1/4" wide. but I remove material from the sides of the bracing to achieve stiffness. Tall and thin, like a tall narrow triangle. This reduces weight, while keeping strength. I've seen different approaches to this. square cross section bracing, wider bracing but not as tall, etc. The torrefied tops i've used have always had a very good ring to the tap. and had good stiffness.
But that is a very small number of them. So I guess what I'm saying is you will just have to check the tops and bracing out one by one, just as with any top and bracing material. I use titebond standard for the tops joint, and or HHG for the bracing to the tops. As I said, no glue joint failures. Yet. Ha!

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