# Thermal Treated Wood



## richgreer (Dec 25, 2009)

The latest edition of Fine Woodworking has a short article on thermal treated wood. I'd never heard of it before.

It darkens the wood. On oak it looks like the wood has been fumed. It makes every wood look darker and apparently it makes the wood more resistant to decay.

One can learn more at www.seasonwood.com.

Has anyone ever worked with thermal treated wood? How many have even heard of thermal treated wood?


----------



## Eagle1 (Jan 4, 2010)

Thanks for the info Rich.


----------



## swirt (Apr 6, 2010)

I saw that little article a couple days ago and wondered how many significant others were going to be rolling their eyes as they watch their wood obsessed mate putting wood in their oven, saying "I saw this in a magazine and I just have to try it."


----------



## richgreer (Dec 25, 2009)

I admit it. The thought of putting some wood in the over occurred to me (when my wife is not home). Something tells me there is more too this than just sticking wood in the oven.


----------



## swirt (Apr 6, 2010)

Might need to send her out of the house for a while, 

Here is the process they describe:

Phase 1: Use heat and steam to raise temperature to 100 C (212 F)
Reduce moisture content to approximately 0%
Phase 2: Temperature increased to 180-210 C (356 - 410 F) for 2-3 hours (temperature and time depend on end-use application)
Phase 3: Lower temperature with water spray to increase moisture content to a usable 4-7%

Sounds like you could do it in a day.


----------



## araldite (Jan 29, 2009)

This caught my eye too and I thought of trying something at home. But I agree, I think there's more to it than sticking some wood in the oven. If I read the tiny chart on their website correctly, it's about a 40 hour process. Wife better be away for the weekend. Also, the heating with steam and cooling with water spray may be hard to simulate. Still, I may try something for fun just to see what happens.


----------



## richgreer (Dec 25, 2009)

It seems like running an oven for 40 hours would be quite expensive. I'm sure the people who do this commercially have a more efficient system.

I find thermal treated wood interesting. I really like the look of fumed white oak but fuming scares me.

I may order a sampling of their wood to see what it looks like for real. I don't expect the working properties to change - but you never know.


----------



## Nomad62 (Apr 20, 2010)

A friend of mine who works at a high end furniture shop showed me some oak like this once, said it's only about the looks, it doesn't make it better; and that it was brittle to work with, but ok.


----------



## Puupaja (Nov 29, 2009)

Hello Rich

Here is link for my projects http://lumberjocks.com/projects/24059 I have used thermal wood many years….

Matti


----------



## JuniorJoiner (Dec 24, 2008)

about five years ago, my local lumber supplier had some roasted birch, which I bought because of it's beautiful chocolate colour and used to make an outdoor bench. 
I had quite a frustrating time with it, as it seemed to be overdry, and split or cracked whenever i tried to work it. it smells something like creosot(not as bad) so I had to wear a mask all the time. as well being so dry, it gave a ton of splinters which seem to fester immediately. 
I have a plank of it left over still in my shop. took a slice off it just this week because I needed to make a cleat to mount a cabinet. same problems.

I think much of the trouble is that it is birch, notoriously unstable anyway. I like the idea of consistant colour and somewhat better longeveity. so I would buy roasted lumber again if the design called for it, just not birch.
hope this helps.


----------



## alnandy (Jun 19, 2010)

Like the rest of you I was intrigued by the heat treated wood and it's beautiful dark colors. However, before I got into woodworking I got an MS in Chemistry and reading the above comments got me to thinking, and worrying.

First, there's a real danger of fire and possibly explosion if you don't have REALLY good temperature control. 200C is not a temperature to fool with, especially live steam at that temperature. You'd have to build your own, basically a steam box (like woodbenders use) on steroids. 200 C steam, if it gets to your skin, is an instant 3rd degree burn.

Second, there's a reason the wood smells like creosote. The very high temperatures used in this process cause the resins in the wood to react, partially polymerize, and basically for tar-like compounds. Creosote is a natural tar that comes from the creosote bush. Creosote is known to be not only toxic, but highly carcinogenic. My guess is that the sawdust and fumes created while working with this wood have a real possibility of being both toxic and carcinogenic.

Third, the high temperatures of this process probably damage the lignin. This is the "glue" that holds the wood fibers together. I suspect that there is significant chemical degradation of the lignin, which would account for the deterioration in working properties of thermally treated wood.

Anyway, without lab data I can't prove any of the above claims, except for the first one. But, my suggestion is that anyone wanting to work with this stuff should do some homework on potential health hazards. Anyone wanting to actually make the stuff should make certain their life and health insurance policies are paid up;


----------



## oldworld124 (Mar 2, 2008)

There is another part to this. Woods with high resin (sap) will not bleed unless it reaches the highest temperature it was brought to. For example, pine that was kiln dried at a low temp, say 100 degrees, will bleed sap when it reaches about 100 or more. So, there is a positive side to this. I have used burnt birch and have some in the shop. It is interesting to work but feels very dry. I prefer air dried wood as it usually retains a better shimmer.


----------



## swirt (Apr 6, 2010)

Just clarifying that I was kidding about making my own.


----------

