Correct me if I am wrong but shouldn't it be baked in the absence of oxygen? I thought the idea was to modify the wood at the cellular level and not cook (slow burn) it.
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What's On Your Workbench?
- Thread starter HaMMerHeD
- Start date
It's... complicated.
Yes, torrefaction is supposed to be done in absence of oxygen, but that was historically more of an industrial process to make things like bio coal. It is typically to prevent carbon combustion (charring) when done at higher temperatures, but at low temperatures, like I was using, that really isn't an issue.
From anything I've read people who have roasted a neck in the presence of oxygen have found a similar product to what you would get from a torrefaction processed piece.
EDIT: this video from Taylor is also interesting. You can clearly see that their oven is not an autoclave so there is definitely some oxygen in there.
EDIT 2: their "torrefaction" is just heat processing in a full oxygen environment. Here is a link to the kiln:
Invalid Link Removed
If that's good enough for Taylor I think I will be fine.
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AIUI, Torrefaction is much hotter, (5-600F) (260-315C) and ignition would be an issue - plus the result might lack a lot of wood-like properties you'd want for building anything but a fuel stockpile with (happens to be the direction I learned about it first from.) I mean, it's the low end of "destructive distillation." "Roasting" is a wee tad less than that.
Is there a risk of warping as the roasted wood reabsorbs moisture from the air? Or does the roasting process prevent that? Or do you have to seal it before it gets the chance?
I’m annoyed I got rid of my little oven now, I could have done some experiments!
I’m annoyed I got rid of my little oven now, I could have done some experiments!
I think the idea is the wood is supposed to move less when reabsorbing moisture, but exactly how much is hard to tell. Popular opinion says it helps and I haven't come across anyone who has used heat treated wood and found that it became unstable.
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Those look great! You may have seen some of my adventures in home roasting here as well. My findings are in line with what you've noted too. Dimensions shrunk on all the pieces I've done. As much as 1/8" on an 8" wide board. One thing I've found is that the oven roasting process seems to do something to the oils in the wood, because the routing dust they make is really fine, but there's an oiliness to them, kind of like soot has. I've also noticed that if the wood has a cup, bend, warp, check, it gets accentuated by the roasting process.
The wood seems to get a little stiffer too but also becomes more brittle. I've cut some thin 5mm square strips and bent them until they broke to compare to unburnt wood. They break with around the same amount of pressure, but the burnt ones deflect less while being bent, and shatter/crack off abruptly rather than splintering like the unroasted.
Another thing I've noticed with walnut in particular is after roasting, I can sand it up to 2500 grit and polish it like a much harder hardwood. In my case, this helps me keep my wood species to domestics and local woods in my builds.
"Roasting" wood, for the good results involves a pressure vessel , and necessitates the absence of oxygen.Those look great! You may have seen some of my adventures in home roasting here as well. My findings are in line with what you've noted too. Dimensions shrunk on all the pieces I've done. As much as 1/8" on an 8" wide board. One thing I've found is that the oven roasting process seems to do something to the oils in the wood, because the routing dust they make is really fine, but there's an oiliness to them, kind of like soot has. I've also noticed that if the wood has a cup, bend, warp, check, it gets accentuated by the roasting process.
The wood seems to get a little stiffer too but also becomes more brittle. I've cut some thin 5mm square strips and bent them until they broke to compare to unburnt wood. They break with around the same amount of pressure, but the burnt ones deflect less while being bent, and shatter/crack off abruptly rather than splintering like the unroasted.
Another thing I've noticed with walnut in particular is after roasting, I can sand it up to 2500 grit and polish it like a much harder hardwood. In my case, this helps me keep my wood species to domestics and local woods in my builds.
Torrefaction - Wikipedia
You are oven baking the maple without pressure, and in the presence of oxygen
You are making coffee grounds, or pre charcoal.
There is little to be gained by roasting in the open air, unless you are hardening a spear , or a viking making a boat .
The torrefaction process involves baking wood in an oxygen free environment at temperatures higher than conventional timber seasoning kilns. Taken to its logical conclusion you would end up with charcoal but stopped short, the wood merely darkens depending on how long it has been roasted.
Well, yes. Torrefaction is generally done at atmospheric pressure, just without oxygen. And yes, if you get the temperature high enough to start oxidation and oxygen is present then the oxygen will effectively burn the carbon and eventually you end up with ash.
Even without oxygen, at high temperatures you are basically making coal. Also not the best stuff to make instruments from.
But at temperatures where pryolysis happens but oxidization does not, you get the benefits of the heat treatment without making charcoal. This image shows the idea:
Pyrolysis - Wikipedia
So you get the benefits of slightly reduced weight with better stability and deeper color (if that is desireable).
I can't find the article, my takeaway is: Absence of oxygen , under pressure, patricularly inert gas prevents / reduces the breakdown of the cellulose to carbon.
Also the article I read indicated that the atmospheric pressure decreased the breakdown of the cell walls from the fast escaping water, and volital compounds being released at such a rapid rate.
Effectively slowing the rate (not volume) of the offgassing.
Yep, I've read several articles on it and the official processes, but following the literally hundreds of examples of home roasted woods, I tried my own, and I'd call it successful. Perhaps there are some concerns about it being partially burnt, but in practice in a guitar or bass, there do not appear to be any drawbacks, only gains. Like hawt, hawt lumber from pieces that weren't so hot before. I've built three necks now with burnt walnut fingerboards, and can't see any difference structurally between them and unroasted walnut boards. The roasted ones polish up beautifully and have a rich chatoyance in addition to the darker colour compared to unroasted pieces.
In addition, it's cheap to get exotic looking pieces. Here are 6 of 8 boards I got out of about 35 dollars worth of walnut. That's under 4.50 each, and four of them are wide and long enough for a 26 fret 7 string bass. 
EDIT: reloaded pic...
EDIT: reloaded pic...
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I also postulate that the dryer the wood is at the start of the process would show profound differences, especially in regards to the destructive off gassing.Yep, I've read several articles on it and the official processes, but following the literally hundreds of examples of home roasted woods, I tried my own, and I'd call it successful. Perhaps there are some concerns about it being partially burnt, but in practice in a guitar or bass, there do not appear to be any drawbacks, only gains. Like hawt, hawt lumber from pieces that weren't so hot before. I've built three necks now with burnt walnut fingerboards, and can't see any difference structurally between them and unroasted walnut boards. The roasted ones polish up beautifully and have a rich chatoyance in addition to the darker colour compared to unroasted pieces.
Heat treating certainly dehydrates the resins and allies them to be solidified and as a hardener, will bond the fibres more tightly.
The point that it becomes brittle is hard to pinpoint, and likely varies widely by species .
My shop will be in place 11/17.
I now have:
A workbench
A 1946 delta 14" band saw.
A scroll saw
A full size and compact router.
Built a router gantry to thickness boards.
Found an ongoing estate sale location that is the size of Costco full of 1000's of tools and the like
A couple sources of quality wood.
A bunch of wood redwood, bay laurel burl, figured okume, figured reclaimed figured american mahogany, padouk, wenge, maple, and basswood.
A friend is bequeathing his grandfather's: 50's Rockwell table saw
Planer King 16" thickness planer (sa-380)
20" Rockwell band saw
Rockwell jointer
24" disc sander
Dust extraction system .
I'm still going to need to run mains to the building. I still need to insulate and install a floor or coating for the OSB.
Oh and bought an HVLP and compressor.
This is the positive side effect of C19.
Business application in the works .
Sweet Treats by Ray
Logo in the works.
Whew the new year looks promising.
I now have:
A workbench
A 1946 delta 14" band saw.
A scroll saw
A full size and compact router.
Built a router gantry to thickness boards.
Found an ongoing estate sale location that is the size of Costco full of 1000's of tools and the like
A couple sources of quality wood.
A bunch of wood redwood, bay laurel burl, figured okume, figured reclaimed figured american mahogany, padouk, wenge, maple, and basswood.
A friend is bequeathing his grandfather's: 50's Rockwell table saw
Planer King 16" thickness planer (sa-380)
20" Rockwell band saw
Rockwell jointer
24" disc sander
Dust extraction system .
I'm still going to need to run mains to the building. I still need to insulate and install a floor or coating for the OSB.
Oh and bought an HVLP and compressor.
This is the positive side effect of C19.Business application in the works .
Sweet Treats by Ray
Logo in the works.
Whew the new year looks promising.
New wood days are always fun. This is a swamp ash beauty. 42" × 19" x 2 1/4". No knots or defects.
Its enough to get 2 one piece bodies and wings for a neck thru. Its crazy light for a board this size.
Its enough to get 2 one piece bodies and wings for a neck thru. Its crazy light for a board this size.
Oooh! Speaking of Ottawa and torrified maple, I have something new on my workbench!
Made in Ottawa, tote and front knob made of torrified maple.
Made in Ottawa, tote and front knob made of torrified maple.
Nice! did you jump in on their seconds sale? I had a really hard time having self-control not getting that same bevel-up jack and a small rabbit plane.
Edit: I meant shoulder, not rabbit plane.
Edit: I meant shoulder, not rabbit plane.
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Actually I went there for the screwdriver! It's specifically for plane top-cap screws.
My Luthier friend spotted the plane in the scratch-and-dent shelf. I couldn't stop myself. It has a ding in the toe from being dropped in the showroom. Dictum in Deggendorf Germany. 210 euro. That's 25% off. includes one free sharpening of the PM-v11 blade.
My Luthier friend spotted the plane in the scratch-and-dent shelf. I couldn't stop myself. It has a ding in the toe from being dropped in the showroom. Dictum in Deggendorf Germany. 210 euro. That's 25% off. includes one free sharpening of the PM-v11 blade.
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The rabbit plane was from a dealer in Berlin. It took about 2 hours of sanding to get the sole flat. But it is 1000 grit polished now.
Got another V125 Vox head. Its a lead version and will go with the rebuilt speaker pictured. I have another chassis coming that is destined for mods for bass use.
