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Here is the latest Luthier Tips du Jour video. - In this video I explain what torrefied wood is and how it is produced.
This video as well as all my other videos are available via my website, http://www.obrienguitars.com/videos , LMI's website or on youtube.
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Interesting. Of course I’ve heard a out torrified wood in guitars but didn’t know it had other uses. What would be the benefit of a torrified facia board on a house?

It is very resistant to moisture.

Robbie—

Does the water resistance make it difficult to use water based glues on torrified wood? I’ve heard rumors to that effect. I love the idea of the wood not reacting much to RH changes, but I don’t want to have trouble gluing the guitar together in the first place.

I have also heard rumors of glue issues on torrefied wood but have not been able to confirm them.

So far I have not had any short term issues using water-based glues with torrefied maple and spruce but my experience is limited. I wet both surfaces with glue (but I do that anyway). I've used Titebond for laminating and and also for braces. Time will tell I suppose. Others have a lot more experience with torrefied wood so maybe one of them will jump in here.

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Steve Smith
"Music is what feelings sound like"

I'm pretty committed to hot hide glue for construction of the guitar, so if torrified wood is hard to glue with hot hide glue, I should not buy torrified wood.

I've used hhg and torrefied wood before and it's worked. I generally use titebond now, and use more glue than I normally might, and definitely clamp longer.

I always clamp overnight. I wouldn't have any problem using HHG and, come to think of it, I did glue the bridge onto the torrefied red spruce with HHG. It's a dred with mediums and the bridge has been doing fine for a year.

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Steve Smith
"Music is what feelings sound like"

this is one of many methods. It is interesting that the steam is used that is the first I heard this method. Thanks for posting.

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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

I just put two torrified top guitars out in the wild so it remains to be seen. At the recommendation of some experienced luthiers here on the forum I used fish glue for the braces and clamped for 24 hours. I used Titebond Original for the bridge and clamped for the same time.

The video reminds me of concerns I've had ever since torrified wood became a thing for instruments.

What is torrified wood and how does a builder know what they are getting when they buy "torrefied" wood? As far as I can see, there is no single standardized method for torrefaction of wood for instruments. Even if a producer of torrefied wood actually uses one of those ovens certified by the ThermoWood Association in Finland as in the video, there appears to be no standardization of parameters used by the wood producers with those ovens. Bob Lennon of Thermal Wood says as much in the video: "The recipes. That's where the intellectual property lies." by which he was referring to the parameters they have developed in-house to treat the wood. Other suppliers sell torrefied wood made using different methods of torrefaction (LMI) or undisclosed methods (StewMac).

Which brings up another question. Assuming that the claimed benefits of torrefaction are real, how sensitive are they to differences in torrefaction methods? Are all methods equally effective with respect to the claimed tonal effects or are some methods significantly better than others? If you buy torrefied tops that you are happy with from a supplier who doesn't disclose their source and six months or a year down the road they change their supplier without disclosing that, can you be sure that the tops will have the same characteristics?

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Once in a while you get shown the light in the strangest of places if you look at it right - Robert Hunter

Interesting subject.
I like the way terrified wood looks,
I also think the wood will possibly last longer.
The glue issue would make me not use it.
It hasn't got a track record yet,
and for me,
the least important part of building is the look.
Might change my mind though.
Alan

JDeR +1

Pat

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Pat

It's my understanding that Yamaha has been using T-Wood for many many years. Of course that goes back to what Jay says in that we don't know exactly what method they use. But the track record I believe is at least somewhat established unless I am mistaken about Yamaha.

I looked up the Yamaha patent for their process a couple years ago. It said their process involves high temperature and steam under high pressure. It didn't call for doing the treatment in the absence of oxygen which is typical of torrefaction, so their method is something other than torrefaction, or at least a significant variation on torrefaction.

They do have a track record with that method though.

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Once in a while you get shown the light in the strangest of places if you look at it right - Robert Hunter

Interesting. By the time the use of torrefied wood has a decent track record in guitar making I'll probably be dead Guess I'll help contribute to generating the track record

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Steve Smith
"Music is what feelings sound like"

I'm reacting the opposite of Steve. I leave open the possibility of experimenting with it someday, after there is a more established track record, but for right now, I am hearing about a bunch of potential downsides in exchange for mixed results on the payoff. I'm not wild about that trade-off.

Gilligan experimented with a new glue that they all thought was awesome, and so they fixed the Minnow's hull with it. They later learned that the glue sticks like crazy for a few days, and then it completely fails. Luckily, it failed while the Minnow was still in the lagoon, not out on the high seas. The moral is to be cautious regarding things that seem too good to be true. They often are. So endeth the lesson, according to Gilligan.

Gilligan Guitars
The Minnow, the Mary Ann, the Howl.....

It is my gut feeling that there is an optimal level of torrefaction beyond which the properties required of a soundboard are degraded. Personally I would err on the side of less torrefication.

On the subject of gluing, have a look at this video by the estimable Beau Hannam:

https://www.youtube.com/watch?v=FHybI5y5byQ

My takeaway from that, is that all those joints easily withstood the amounts of stress a guitar would experience in normal usage, save perhaps the bridge...

I use liquid hide glue (OBG) to joint and for the braces. I only use torrefied braces on torrefied top.

I've done 17 torrefied top guitars over the last few years. I also clamp for 24 hours.

I can confirm that first-hand, and so can Martin guitars. At least with Titebond, they had issues with bridges staying on their early torrified tops ... which internally they will say were "over-torrified" by their supplier.