Baking vs Torrefaction

[sinistral]

Originally Posted by printer2

I was looking for a particular paper as it had a really good graph showing the decomposition to temperature, maybe I will try again yet. Assimilating the information I had on torrefying wood I learned the chemical side of wood bending. This was back in my early days of building and I was still working on my method, with all the different temperatures people use, mist with water or not, kind of confusing. The use of water lowers the temperature needed to bend with, I seem to recall the amount of water vapor changes curves when torrefying wood. I do like the look of baked wood, not too enamored by torrefied wood though.

I was more interested in the stability it can give to humidity changes. I started to do an experiment, I had three sets cut next to each other and I heated them all just above boiling to drive out all the moisture. I then heated two sets to below where torrefaction takes place to any great amount, then torrefied the one. Humidified them and then set the torrefied one aside. Then I repeated the heating of the other two to their respective temperatures. Rince and repeat a number of times. Then I wanted to test the wood and then make a mule that I could swap out the tops to see how they faired. Sadly everything got interrupted before I could learn anything (oh yeah, used to work in a mechanical test lab) and the plates got mixed up with my other wood. I did have another set that were not cut along side the others, did the same to it as the middle one above but after baking I stuck it in the freezer for a few days and then humidified it then back in the oven. I wanted to see if I could 'season' wood driving moisture in and out many times and see if I can make it an 'old' piece of wood without waiting for years. I will have to try it again some day.

Basically, a time-warp recreation of the air-drying/seasoning process employed by Martin in early 20th century of storing wood for years in the attic of the old factory before making an into guitars. Interestingly, Atkin employs a freeze-thaw cycle as part of their finishing process.

Another thing, I think, that goes a long way—in regard to the particular sound of an Atkin acoustic guitar—is the finish we use. We grain-fill the back and sides, then spray eight coats of thin cellulose. After we sand those down to polish, we put them in the freezer. Then, they go in-and-out of the freezer. Finally, once the wood has settled down, we sort out the geometry of the guitar and put it all together.

By the end of our process, each guitar has been through a pretty full-on temperature treatment. And I think, when we put the guitars through that, all those good things we love about old touring guitars that have survived those conditions, naturally, are left in the wood of an Atkin guitar—even before our guitars have been assembled! I really believe that has a great effect on the sound of the instruments.

Originally Posted by ytse43

I'm going the (simplified--please don't ROAST me!) linguistic route here. 'Torrefy', also 'torrify', comes from Latin, hence its usage in French. 'Bake' and 'roast' both have Germanic roots.
So, might the word one uses depend on where one grew up?
Regarding this heating process as it pertains to musical instruments, 'torrefaction','torrefying', 'baking', and 'roasting' do get used interchangeably by many of us, as being pedantic is not something most people pursue.

Now, as to this/these process/es being distinct enough to warrant specific use of those words is what other posts here have already gone into.

I have it in my mind that YAMAHA was the first to go mainstream with their A.R.E. (Acoustic Resonance Enhancement ) 'wood reforming' process. https://www.yamaha.com/en/tech-desig...hnologies/are/

Interesting, the words 'torrefy' 'roast' 'bake' 'heat' 'cook' 'fire' 'pyro' are not used in the article, only 'wood reforming'.

Side note: Japanese charcoal briquettes are considered by many to be the best. Japan connection coincidence?

Grammar note: I went with single quotes, despite me being American. Easier on the eyes, and I'm also freed up to put commas outside!

My understanding is.that Robin Boucher was the first builder to use torrefied wood in guitar construction. Boucher is pretty secretive about his/their process.

[Tim McKnight]

Shou Sugi Ban (or Yakisugi) has been used by Japanese since the 1700's, to treat wood with fire, which is likely before Yamaha? I am not sure who really gets credit for wood treatment as we could go all the way back to Cremona Italy where the early 16th century violin makers were experimenting with different wood treatments to enhance the tone of wood. Or we could go all the way back to the Biblical days of King David who is credited with building over 6,000 instruments for the use of praise and worship. It's quite likely he was doing his share of experimentation as well. I am sure many will go forging on ahead of us in the quest to reinvent the wheel and improve on proven traditions. Heck, that's just the fun of it which makes many of us tick.

I guess in my mind I (personally) differentiate 'Baking' from 'Torrefaction' by the amount of heat involved. What is that specific heat threshold you ask? I dunno? Baking (to me) is in a conventional household oven at lower temperatures in the presence of oxygen while torrefaction is higher combustible temperatures within a controlled oxygen evacuated vessel. Right or wrong, that's how my mind quantifies the separation of the two processes.

[ytse43]

"We were the first to introduce torrefied Picea Rubens soundboards." Well, who is to argue with that?!
However...Adirondack spruce is specifically mentioned...so perhaps it is I who argues with that! (All in good humor!)

The process works; this is what matters.

[ytse43]

Originally Posted by Tim McKnight

Shou Sugi Ban (or Yakisugi) has been used by Japanese since the 1700's, to treat wood with fire, which is likely before Yamaha?

Definitely before Yamaha! I was just (lightheartedly) speculating that inspiration may have been taken from the charcoal making process.

I am with you with 'baking' meaning what most of us know it to mean, and 'torrefaction' being a process with multiple parameters to be worked with.

[beninma]

They all have different processes and I'm not sure I have to know about it to know whether I like it.

I have a Taylor now with a Torrefied top. It acts like a normal acoustic guitar. It might sound different than it would without torrefication but I will never know, AFAIK there is no guitar with the same wood & body shape without torrefication. I like that guitar a lot, but it's a normal acoustic guitar and it needs just as much truss rod adjustments and just as much attention paid to humidity/care as any other.

On the other hand I have two electric guitars that are both solid body:

- An Ash body w/Maple neck

- A Korina body w/Torrefied maple neck

Both of these electric guitars have similar (different color) kind of see through gloss poly finishes with matte necks.

There is a dramatic difference with that torrefied maple neck. I believe the manufacturer just calls it "roasted", but whatever the difference that guitar is definitely superior in terms of it's neck being outrageously stable, it needs far fewer truss rod adjustments than any other guitar I've had.

[printer2]

From my readings I have set a lower limit of 350 F where the hemicellulose decomposes without taking forever. Will it do the same at this temperature as compared to 385 F? One way to know if you T'd it is the top would turn opaque. Does it turn opaque between 300 - 350 F? Next time I do cookies I'll give it a try. The electric guitar guys have done a lot of hardwoods in the oven, mainly maple. Some have done them at lower temperatures, speaking of cookies...

https://youtu.be/c8R_4lT_KIs?t=789

[ytse43]

Spoon! (Points given to anyone who gets this reference)

Convection oven, so hot, circulating air, and also fluctuating temperature. Not a precisely-controlled environment, but a fairly consistent one. She readily acknowledges the trial and error needed to get the 'recipe' she wanted. Lovely spoons. Delicious cookies. Savory lasagna. (Adjective of choice) guitar tops!