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The key to the process may be the amount of torrefication used. Commercially torrefied lumber may too crisp for good tone wood. The guys at Martin seem to understand this. I wouldn't want to build with "driftwood" dry wood, but I do like spruce when it is about 50 or 60 years old.

I have 50 year old spruce, and it does not feel like the torrefied stuff at all.

But it doesn't feel like new wood either, does it? So could it be described as just less torrefied?

No because presumably it hasn't been through any deliberate thermal treatment. So it's not torrefied at all, just very well seasoned.

I have some recent experience with roasted maple. It doesn't bend very easy but seems to be brittle - I gave up making tight bends (there's a thread on this). On the iron I just didn't feel it release like the natural maple. If you put water on it, it gets wet so it may be more stable with humidity changes but not immune by any means. Finally - no problem at all gluing with Titebond. I doubt if there will be any issues with HHG, fish, or CA. Of course I'm talking maple and not spruce. I would expect spruce to be better behaved.

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Steve Smith
"Music is what feelings sound like"

There have been examples of torrified wood used by obscure manufacturers with import instruments for years now. One example that we encountered was a maple fretboard that had been torrified and was used on an electric resonator.

The material, at least in that case, was completely unserviceable in so much as carefully "lifting" frets resulted in not just chipping but large chunks of the fret board crumbing and falling off.... In the end we scraped off the entire fret board and we have our pal Andy Birko making us a replacement.

Of course I can't speak to the level of torrification that this manufacturer went to and that's an important distinction as well. But I do know from personal experience that at some levels the material becomes a crispy critter and in this case made the instrument basically disposable when the economics of repairing it aren't there.

Don't get me wrong I'm not an anti-torrification nazi by any means but I am skeptical and will wait for one of the fat ladies that you guys craft to sing before passing judgement. I also wonder how that all important bridge glue joint will do or if unnatural acts such as hardware.... will be required to keep things in place.

Part of me does want to say something such as sheesh we have Tonerites...., torrification....., fossilized Mastiff Turd.... etc. Doesn't anyone want to wait and be part of the opening up process of a fine musical instrument anymore.... What's the hurry....

Some tests that I would like to see are:

1) Gluing tests simulating all manner of the important joints on an instrument with specific interest in bridge glue joints under constant tension with RH swings..... You know, real life...

2) Dent and ding resistance tests, could be fun to do...

3) Weight and stiffness with deflection testing prior to and after torrification.

4) Finish adhesion testing.

5) And the big kahuna blind listening tests of two identical instruments with the only difference being the top one torrified, one not. Would like to see this test done when the instruments are brand spanking new, after one year, and after five years. If you could plot results going out several decades one has to wonder if at some point there are diminishing returns.

6) Lately we feel like proctologists in so much as this is our busy season and we are up to our elbows in cracks.... No jokes please, well maybe a few... Anyway about half of the repairs that we are doing at present are crack repairs be it spruce, mahogany, rosewood, etc.

Part of the drill with a dried out instrument is to rehumidify and let the natural swelling of the wood aid in closing the cracks. As such one has to wonder how well torrified wood will retain the trait of swelling when exposed to high RH. Sure you can make the case that torrified stuff is less likely to crack because of RH swings in the first place but not all cracks are from RH swings. You have clients that sit on guitars, jealous lovers that throw them down the stairs, the Martin that was shot with a shot gun that we repaired, you name it.

It could be that all this stability, if this is actually the case, could require different repair activities to deal with it.

Lot's of questions and so little time so you brave guys who are on the bleeding edge of torrified tops thanks much for reporting to us as you are.

I am very skeptical about the long term durability of heat treated wood. Is there any data around comparing the toughness of torrefied wood to kiln or air dried wood? I expect fractures and other structural problems will start showing up soon.

The fact that this even exists is kind of funny because when I first got into this hobby, even kiln dried wood was seen as nearly a mortal sin.

I guess we'll be able to make guitars as good as Yamaha? They have been using torification for years and at least five years on guitars maybe more

http://www.yamaha.com/about_yamaha/research/are/

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Ken Cierp

http://www.kennethmichaelguitars.com/

Guitars are predominantly made from wood. Wood expands and contracts. A guitar is always in motion, RH wise. Torrefied wood doesn't expand and contract? What, if anything happens to the guitar? I've got zippo guitar building experience, but know a fair bit about building furniture, cabinets, and wood movement. I know that guitar construction is at odds with some rules of woodworking, ie. cross grain gluing, but that allowances are made for this during construction, but what happens when you take top movement out of the equation? Are there any immediate considerations? Long term considerations?
What happens when tops that are off quarter or have run out are torrefied? That one I think I can figure out myself.
I'm not being a naysayer about torrefied tops, one way or the other.
I'm interested in what the experienced and knowledgeable have to say about this, because my knowledge is VERY limited. I asked a lot of questions as a kid, so I guess I haven't grown up yet!

Alex

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I will gladly jump on the band wagon in 5-10 yrs . Until then I will take my wood fresh and my pop-tarts baked .

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Michael N. wrote:
"No because presumably it hasn't been through any deliberate thermal treatment. So it's not torrefied at all, just very well seasoned."

One of the interesting features of torrified wood is the reduction of hemicellulose, which also occurs in well seasoned wood. There might be some benefit to lightly torrifying soundboards to get that reduction of hemicellulose, if that in fact, improves the sound of the finished instrument.

this doesn't make the wood more brittle. I have made 2 guitars with this and they sold . They do have a different sound. The tops are very stable. The glue takes a little longer to dry as the tops don't absorb any water so you have to wait for them a little longer. I allow 24 hr clamp time.
They look old guitars without having to add toner. All I can say is it is just another thing a builder can offer to his clients. Last year Martin had the first of the torrified tops out for edapolusa and the 2 they had sold on the spot, they do have a more vintage sound than anything I have heard before.
The only way you can be sure is to make a guitar with one and decide for your self.

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John Hall
blues creek guitars
Authorized CF Martin Repair
Co President of ASIA
You Don't know what you don't know until you know it

For this experiment to really work you would also need to use torrefied braces....

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Old growth, shmold growth!

I used torrefied braces on mine. We'll see what happens...

It does make it more brittle, without question. It's a side effect of the torrefication process. Even Martins more gentle method results in a wood with increased brittleness, they admit it here:

http://onemanz.com/guitar/martin-vts/

Whether that greater brittleness is anything of a problem? I have absolutely no idea.

So it seems they wish to replicate the tone of wood that is a couple of hundred (or more) years old.
That may seem a little odd. Virtually all the blind tests done between the best modern Violins and the 300 year old Strads and Guarneris put the Modern instruments (non torrefied) ahead. There have been some notable rigorous tests done on this, not to mention many, many more that have been less scientifically rigorous. . . . but still blindfold. The modern instruments fair extremely well when the blindfolds are put on. They just don't do very well when the blindfolds aren't put on. Which should tell you a lot about how open we all are to suggestion.

Whether the torrefication process results in a wood that is exactly like that of 300 year old wood is another matter. It just may be that it changes things in a slightly different manner (who knows, perhaps even for the better), yet looks very similar under the microscope.

Another perspective.

http://bourgeoisguitars.net/wp-content/ ... rs-MMR.pdf

Would be nice if some of the suppliers of torrified wood would make samples available for folks such as us who would be interested in doing some testing.

It's understandable that those with skin in the torrification game would be defending the process and others would be being who they naturally are with new ideas. Seems the only way to break through to the other side (love that song....) is testing.

I'm of the same opionion of John. If you want to know how it all unfolds, build one for yourself.

I purchased a torrified top for the same reason I first bought a Lutz and Carpathian top, I just wanted to see how they sounded.

Also, as many have mentioned here, companies such as Martin, Taylor, Bourgeois, Huss Dalton, and others are offering their warrantee's on these instruments. I would have to think that there were some back room discussions about any possiblities of top failures and claims?

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Guitar Building = Continuous Improvement Process

Wood is so different from piece to piece. The best way imo to test the brittle factor would be to take a set of bookmatched wood. Torrify one side and not the other. Then test away.


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Zeke M I do a torrefied poptart every once in a while.

Hesh .. you had it partially right .. the show is actually going to be called "Breaking Heshtone", where a cancer stricken luthier goes around finding and trashing all the Heshtones he can find, and then charges outrageous fees to fix them....

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Tony Karol
www.karol-guitars.com
"let my passion .. fulfill yours"

+1. IMHO, they are wasted motion, and lack feel. I prefer 12:1.
I have only played a few torrefied guitars, and I cannot see any great advantage...other than the stability. My solution for that is to use aged spruce.

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John

You should give the 21:1 a try,

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MK5acoustics.com

In Soviet Russia, guitars torrifies YOU!!

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