Thermally Modified Wood

[Tom Bender]

Thermally Modified Wood - Has anyone worked with this? Is it suitable for furniture? It looks like it could add some color to otherwise bland wood.

[Paul Tubergen]

I have used the poplar. Machines well (like poplar). Many of the characteristics carry over but it is dark thru and thru. I used it for a bunch of picture frames...

[Grant Wilkinson]

I've used torrified ash for stools and picture frames. I've used it as an accent strip on a cedar strip kayak, too. It stinks when working with it, but otherwise, it works very well.

[Bruce Walters]

Anything that is done differently for finishing? I've been working with some modified Ash and am planning on using boiled linseed. Curious if there's anything I should know or expect.

[Nick Decker]

My wood monger sells it as "Cambia Ash", and I've used it on a few small things like boxes, mostly because of its dark color. I would think it would be fine for furniture. The marketers claim that the molecular structure of the wood is changed (killed) by the heat, which virtually eliminates movement caused by expansion and contraction. (Note that I used the word "claim.") I have noticed that it seems to stay flat after sawing and planing.

I've noticed no difference in the way it glues or finishes, but I've only used varnish on it.

[peter gagliardi]

There is a significant reduction in strength once treated, so choose where to use it accordingly.
I had a job specifying 1 1/2” squares of it in ash to be used for stair newels. I refused to use it in that critical of an application, and used 1 1/2” Ipe instead . Everyone was happy.

[Jim Becker]

I have not used it yet, but I find it very interesting and attractive. The process pretty much eliminates moisture via changes in chemistry. I had not heard what Peter mentions about strength, however. I've been considering buying some to test for use for some smaller things I make simply because of the rich color.

[Joe Wood]

Has anyone heard of or seen T modified 2x10 and 2x12?

[Nick Decker]

Here's a box made with it and regular ash. This was right after I got my i-Box jig and yes, I just had to try one with contrasting wood. It gets even darker, of course, with finish. Almost black like ebony.

[Jim Becker]

Nick, that looks nice...and validates my idea to try some for my CNC produced boxes and ornaments because of "that color".

[Nick Decker]

Thanks, Jim.

[Chris Fournier]

Wouldn't kiln dried be thermally modified wood? This is a rhetorical question!

[Nick Decker]

Thermally modified takes it to a higher temp, which is what darkens it. Kinda like baking it but not burning it. I guess.

[Bill Dufour]

Is this done from one solid piece of wood or is it friction welded from smaller pieces like plywood? i am not aware that friction welding of wood has moved outside the lab.
Bill D

[Jim Becker]

Wouldn't kiln dried be thermally modified wood? This is a rhetorical question!
As Nick mentioned, Thermally Modified is well beyond kiln drying. In a nutshell, the wood is "baked" at high temperatures, but avoiding combustion. The material actually changes chemically so that it's no longer prone to absorb moisture.

[Larry Edgerton]

Wouldn't kiln dried be thermally modified wood? This is a rhetorical question!

Its done in a large vacuum chamber Chris, which is what allows the higher temps. I played with some looking for an alternative to Azek that was more fun to work with but the availability and cost are still too high. It is much more brittle that the original species I noticed, but mostly it is the cost that killed it for me.

[Grant Wilkinson]

@Bill Dufour: The product that I use is one solid piece of wood, usually ash or maple. It's not thermally welded layers.

@Joe Wood: I've seen 2 x 4, and 1 x 6, but I've not been looking for anything bigger, so it may well be available.

[Tom Bender]

A big reason for using exotics is color. T'wood could provide some options.

(T'wood = toasted wood)

Sources anyone?

[Nick Decker]

I get mine from Metro Hardwoods near Kansas City (Independence MO). They're a subsidiary of Liberty Hardwoods (I think), which might have a retailer near you. As I said, the commercial names are Cambia Ash and Cambia Poplar. I see they also do red oak and soft maple, though I haven't seen those.

My guy told me they recently sold a bunch of the ash for tables in a restaurant remodel.

[Nick Decker]

I would add that I've never seen a knot in any Cambia that I've purchased or seen in the store. My guess is that they only select clear lumber for processing.

I forget exactly what I paid per bd. ft., probably a couple dollars more than regular ash. The overall price would probably vary depending on your location. Also, Metro Hardwoods is more of a retail store than a traditional lumber yard, so I'm used to paying higher prices. Not as high as a Woodcraft/Rockler, but higher than some are used to.

[Jim Becker]

The "specialty woods" division of the local, independent, full-service lumber yard/home center near me carries "toasted" wood. They market it to builders/remodelers.

[Bill Dufour]

I seem to remember people would take small pieces of wood and bury then in hot sand to change the color. This same process is used to sterilize instruments during surgery. The local high schools seem to have switched from staining to using a propane torch to color pine projects.
Bill

https://priorclavena.com/steam-autoclave-sterilizers/dry-heat-sterilizers-vs-steam-autoclaves/

[John TenEyck]

My local hardwood supplier has talked about carrying it. I haven't been there in awhile but hope they do because I'm seriously thinking of using the ash for an upcoming house door project. It seems to address every disadvantage of using regular wood for an exterior door, unless you want a light, natural color.

John

[Art Mann]

There is an import shop in the town near where I live that sells it along with other exotic imports. This thread has convinced me to go buy some and see how works and carves. It looks really attractive.

[Yathin Krishnappa]

I used torrefied maple for a the seats of a teeter totter to provide contrast for the white cedar frame, and found it to be very brittle. It lasted about a day when my nephews showed up. :-)

[Nick Decker]

I'll be interested to hear how that goes. I've never tried carving, but would think its brittleness might be a problem? It cuts and routs fine, but that's with high speed cutters.

[John C Bush]

I had a wood stove in my old shop and thermally modified all of my mistakes!

[Steve Kohn]

Where can you buy the thermally modified wood?

[Tim M Tuttle]

I get mine from Metro Hardwoods near Kansas City (Independence MO). They're a subsidiary of Liberty Hardwoods (I think), which might have a retailer near you. As I said, the commercial names are Cambia Ash and Cambia Poplar. I see they also do red oak and soft maple, though I haven't seen those.

My guy told me they recently sold a bunch of the ash for tables in a restaurant remodel.

I saw that stuff at Metro the other day. Looks good.

[Larry Edgerton]

Jim it is heated in a Vacuum chamber, changes all the rules. I looked into it for an alternative to Azek, but the cost and availability are still no good for me. It is more brittle than the original untreated species as well.

[Jim Becker]

Where can you buy the thermally modified wood?
Best source for me is my independent full service lumber yards "specialty woods" organization since it's primarily marketed to builders.

[Chris Fournier]

My question was intended as tongue in cheek. By definition kiln drying thermally modifies wood. Simple as that. A poor joke I guess. Over twenty years ago I worked with a supplier who was figuring out vacuum kiln drying, I never saw so much nasty thermally modified wood in my life - modified from lumber to garbage just like that - degrade and workability were deplorable. No doubt others have figured it out, these folks simply didn't. The idea that you can vacuum kiln wood to the extent that it no longer is hygroscopic will require some serious explaining for me to accept.

[Brent VanFossen]

Lee Valley is using torrefied maple on some of their plane and handsaw totes. It's beautiful.

I've also seen it in maple and poplar at one of the better lumber sellers in Portland, OR.

[Jim Becker]

My question was intended as tongue in cheek. By definition kiln drying thermally modifies wood. Simple as that. A poor joke I guess. Over twenty years ago I worked with a supplier who was figuring out vacuum kiln drying, I never saw so much nasty thermally modified wood in my life - modified from lumber to garbage just like that - degrade and workability were deplorable. No doubt others have figured it out, these folks simply didn't. The idea that you can vacuum kiln wood to the extent that it no longer is hygroscopic will require some serious explaining for me to accept.

My understanding is that the much higher heat levels used to "bake" the wood changes things chemically. If the wood was exposed to normal air during the process it would become glowing coals I suspect... ;) There's little or no danger of combustion with normal kiln drying processing but for "thermally modified" lumber, there is. At least that's the way my local supplier 'splained it...