Thermally Modified wood

T

Taximanny

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Jul 27, 2015
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Found some of this at the woodcraft store. Really nice figured maple.

Read up on it and it's supposed to be treated in a high heat process to make it super stable.
Anyone use it yet??
 
I wonder if it is something like the stuff I picked up. They called it Roasted Curly Maple. It is roasted in a kiln and takes on a nice darker color and the dust from sanding it has a slightly burnt smell to it. It is really beautiful wood to work with. One of my favorites.
 
That's interesting - I'd like to know more about the process. Since it says "no chemicals" I wouldn't think it's been stabilized. Looking forward to more info.

edit: OK, I did a bit of looking and found this info:
https://en.wikipedia.org/wiki/Thermally_modified_wood

There seems to be 5 different processes to get the desired results. The article above describes all 5.

On down in article I found this tidbit that might be of interest to knifemakers:
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The main disadvantage is that the strength is decreased as a result of the high temperatures. In general the bending strength is reduced up to 30% with more reduction at higher temperatures.
The biological resistance against some (not all) micro-organisms and insects is improved. Shrinking and swelling is reduced up to 50–90%. The treated wood is somewhat darkened in colour. As a principle the heat treatment process can be done on all wood species.
*****************

Ken H>
 
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I've found that it's used a lot on guitar parts... Where stability is a must, like the necks.
I'm milling it up now into scales... Gonna try some stains on it to.

Wouldn't want to use it on high stress handles like an axe, but for scales it should be sweet.
 
But is it stabilized or just heat treated. How will this wood respond to moisture and humidity.
At my work "lumber mil" I am a boiler operator and runt the boiler and kilns. We heat treat wood and it does make it harder and less prone to warping but it still soakes up water like rain.
 
JT, from my reading it says no chemical additives, so I would NOT expect it to be anything like stabilized wood. Depending on process used, it could be heated under pressure, and perhaps some additives. Since the example above says "no chemicals" I would not expect they used any additives at all.
 
I'm treating it like a wood that doesn't need stabilized.
Still gonna seal it up with Tru oil.

I'm sure they have some kind of Patton on their process..

Im thinking they are making it as Stable as are stabilized wood.
Although are meaning of stabilized is waterproof.

I've done a few test pieces with the Tru oil and it penetrates all the way thru.
It soaks it up like a wick. And the color really pops without staining.
The roasting process darkens the tighter grain.

Yes Ken
It's heated under a vacuum.
 
Yes, it's really nice stuff. Here is a knife I made with it. Natural color, just oiled.

85f7b3c59c6c4ff56a9f187e108b81e3.jpg
 
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Taximanny said:
......... Im thinking they are making it as Stable as are stabilized wood.
Although are meaning of stabilized is waterproof.
Click to expand...
Yes, stabilized does mean a wood should be 99.9% waterproof.

I've done a few test pieces with the Tru oil and it penetrates all the way thru.
It soaks it up like a wick.
Click to expand...
Since it's soaking up Tru Oil like a wick, it doesn't seem like it's at all waterproof. BUT, Wikipedia says "Shrinking and swelling is reduced up to 50–90%" - sure doesn't seem like swelling would be reduced if it's soaking up water (Tru Oil). OR - maybe the water (Tru Oil) is just filling voids in the wood that doesn't stretch the cells as in untreated wood. This would allow soaking up without the associated swelling.... maybe?

.........It's heated under a vacuum.
Click to expand...
Wikipedia says there are 5 different processes for this type of wood. One is under pressure, the other 4 are under steam which usually does create pressure. Not sure which process is under a vacuum, but I'm open to learning.

With that all said, it sure does look good in that finished handle.

Ken H>
 
i think this has been around for a long time. cavemen used to "fire harden" their spear tips before they invented stone points. they would nearly char the tip just to a dark brown in a bed of fire coals ( not much oxygen in there) and the point would become much harder and resistant to snapping off. i used to be into survival and caveman/ american indian stuff and i thought it was B.S. so i tried it myself and was surprised how well it worked !
 
It is nice stuff, but for a knife I have it stabilized as any other wood. It is dead dry, so it absorbs the resin very well. If you are someone who prefers oiled woods ( not my thing), then use true-oil or whatever you like.
 
heat processes just have the wood getting old quickly. Hence more stable and more dark. We can expect less movements.
Obviously different kinds of wood need different sealing treatments since their pores and fibers, content of oils etc.. differs, remaining the same for each kind of wood regardless the aging.
Open pores aged woods need to be sealed in any case.
 
I have to wonder though, I saw a sharps rifle stock a while back that had been over cooked at the kiln and the walnut was chippy and flakey all the way to the center. It had broken under recoil and I got it played with it a bit. My father used to make pens and he told me he had to soak it in thin super glue to get it to stop flaking while turning. Shame, it was a nice figured stock. What I wonder is if this would have the same issues?
 
Here's is one I just finished up with it.
No staining just three coats of Tru Oil and two coats of carnuba wax hand buffed.
I have plenty of the block left.
I'm thinking I'll send some off to be stabilized and see if there is much of a difference working it.
 
What happens in woods like curly maple is that there is a difference in the sugar content between the rings of summer and winter. When baked at just the right temperature, the sugar turns dark, creating a darker contrast in the curl. This is called carbonification. The rest of the wood turns slightly darker, which looks good.

As noted, overbaking and making the wood too dry can break down the organic molecules ( lignin and stuff) that hold the wood together. It can become brittle. That is why I recommend having it stabilized for knife handle use.

In buffing figured woods, the figure usually "pops" with hard buffing on a clean muslin wheel and very little polish. This is due to surface heating of the sugars, essentially burning them more than the wood. Other woods, like blackwood and ebony, also darken significantly with hard buffing due to similar changes in the resins. Over buffing must be avoided, as it can cause checks to form on the surface (now or later on).


A chemical reaction with the sugars will also create carbon. This is what is happening when you use acid on curly maple hawk handles and gun stocks (usually followed with various dyes).
 
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