roasted hard maple

[Stephen White]

I can not really find much on this other than that its a 2nd kiln drying process used to thermally treat it and makes the wood less likely to react to moisture and that its all the rage right now in guitar necks. Makes sense. I am looking for wood options for serving/cutting boards and thought this might be a good choice.

Anyone use it for any projects?

[Erik Loza]

I've never heard that term before but the basic principal for thermally treating any wood is to superheat it in an anoxic environment. Since there is no oxygen, there is no combustion. Otherwise, you just make firewood. I would imagine it should be totally fine for cutting boards since they use regular maple for that, anyhow.

Erik

[Andrew Pitonyak]

I have never used it directly. I first saw it on the Lee Valley chisels.

https://www.leevalley.com/en-us/shop/tools/hand-tools/chisels/bench/69847-veritas-pm-v11-bench-chisels

I have seen the wood called "roasted, thermally modified, and/or Torrefied.

I believe that they reduce the water content to about 4% to 10%, vacuum seal it (reduce oxygen), and then heat it to a much higher than normal temperature (360 F maybe) for some hours. I think that moisture content is reduced to near 0% and finally, the moisture content is increased back (3% to 6% [ish]).

I believe that it seals some parts (cellulose I think) so that it resists warping and movement. Could say stable with humidity and temperature changes. You know, stronger, stiffer, better than before! :-) well, actually, in some ways, the strength is actually reduced shear strength.

I have heard it said that wood has a clearer tone but I am not really sure what that means (less harmonics, better sound in a stringed instrument, etc...)

Lee Valley states:


The hard maple handle has been torrefied, a heating process that changes the structure of the wood at the cellular level, stabilizing it against swelling and shrinkage caused by humidity changes.

Of related interest:

https://en.wikipedia.org/wiki/Torrefaction

I think that if you are gluing the wood, you need to take special care because it usually has lower than normal moisture content (and some wood glues use that moisture).

I like this article about it

https://robcosman.com/pages/newsletter-article-torrefied-wood

You will notice the following quote (related to your desire for the wood):


Great cutting boards that are impervious to water damage

Very interested in what you choose to do.

My interest was related to exterior doors.

[Prashun Patel]

From what I can tell, heating the wood chemically alters the wood to be less prone to moisture and movement. These things make a more stable piece which might be great for chisels and winding sticks. But for things that require substantial strength, I would wonder if the conversion of the connective tissue in the wood would lead to a weaker piece. If you think a bigger threat to the neck is movement from moisture then I guess it would be good. If you think the bigger threat to neck movement is from tension or your truss rod, then it might not be a good thing? I don't know. Just riffing.

[Richard Coers]

Wikipedia says the strength is reduced 30%. https://en.wikipedia.org/wiki/Thermally_modified_wood
Not sure why you want the extra expense of the wood in a simple cutting board. I find enough different colors in domestic wood to satisfy that need.

[Richard Hutchings]

I think they have found a needless way to charge more money for wood. Not that I don't believe in the science behind it, I just don't care and won't be paying the upcharge.

[Stan Calow]

Torrefied wood is currently a "thing" in the making of guitars, as its supposed to make them more resistant to humidity swings. One of the local woodworking stores occasionally has some torrefied lumber.

I'll admit that I tried to do this at home once, in the interests of science, after reading an article in a British woodworking magazine. Rather than baking it in the oven (and potentially creating grounds for divorce) I used my propane BBQ grill. I wrapped up a couple of small logs of soft maple in some layers of aluminum foil, and put them on the grill at around 400ºF for a few hours. I didn't think the results were particularly attractive, and ended up not doing anything with them. For a cutting board, if it doesnt enhance the function of the board, then it doesn.t seem worthwhile to me.

[Stewart Lang]

I've used thermally modified ash before for a large desk project for a customer. Yes it's the same as roasted, torrified, etc. Here are some things I noticed:

It's not impervious to water. As in, it's still wood and will soak up water, but apparently it's very resistant to rotting. I don't think that's a big concern for a cutting board anyway though :)

It's much more brittle. When picking up large sections of a desk with my hands, the sharp freshly milled edges would break off much more easily than any other species I've worked with. This doesn't translate into being softer though, I think it's still relatively hard. But it seems like it's so "dry" and from my knowledge the cells get "crushed" from the process due to removal of moisture on the cellular level. It's hard to explain and I'm certainly not an expert, but it's just much more brittle.

It's very pretty! It's not like walnut, it's much darker and more reddish. But it's very pretty. And it's much cheaper than walnut. I was getting 8/4 Thermally Modified Ash for around $4-5 from my supplier, where as Walnut would have been around $11.

Overall I do like it, except for it being more brittle. But the color is worth it, and it's really not that expensive, compared to other species. It did seem a bit more stable, but it wasn't a big factor in my project so I wasn't too concerned about that aspect.

Here's one major manufacturer of it. You can find some more info on their website: https://www.thermoryusa.com/modification/

[Stephen White]

Yeah sounds like not really they way to go. I think I will s-can the idea and just stick with regular hard maple.

Thanks for all the input!

[Jim Becker]

There is "roasted" and there is torrified. The latter changes the wood chemically. The former may or may not get that far. The big appeal for guitar necks, aside from possibly being more moisture stable, is the color. Some folks who build are actually "roasting" their neck blanks in their kitchen ovens...not something I'd do! One of my local suppliers sells some species that are torrified for architectural purposes. I haven't tried any yet, but it's on my list. :)

[Tom Bain]

I’m curious if anyone has tried bent lamination with torrified wood? The comments about it being brittle make me think that it might be a real challenge to bend.

[Jim Becker]

I’m curious if anyone has tried bent lamination with torrified wood? The comments about it being brittle make me think that it might be a real challenge to bend.

Since most methods for bent lamination requires use of heat/moisture to soften the cell structure for the bend, other than very gentle curves, I'm guessing it's not going to be a joyful experience with torified lumber.

[Prashun Patel]

My gosh. I could be wrong, but torrified wood would be the WORST wood in theory to try to steam bend.

Steam softens the lignin (connective tissue) in the wood, allowing it to be temporarily bent, at which point it re-hardens. As the wood dries the lignin sets more permanently. Air dried wood is harder to bend than green. Kiln drying accelerates the drying so it's even harder to steam bend than air-dried. Torrification would be a further extreme of kiln drying. It would probably be too brittle (in general).

[Tom Bain]

I wasn’t thinking steam bending as I agree that would probably be a complete non-starter with torrified lumber ... just thin strip bent lamination with glue and pressure. The reason I ask is I have an outdoor chair project in the offing that has some bent-lamination components. I would certainly do a test bend first. Just curious if anyone had actually tried it.

[Jim Becker]

Tom, it may work as long as the bend is gentle. You'll want to use an exterior suitable adhesive that has a long open time so you can "work the clamps"...I'd probably go with epoxy here.

[Tom Bain]

Jim -- I hear you ... I typically use Unibond (plastic resin) for any bent lamination work regardless of whether it's indoor or outdoor, because of the long open time and the lower probability of creep. If I do end up trying a test bend at some point, I'll let everyone know how it goes ... or doesn't!

[Jim Becker]

I hope you'll post a thread if and when you test it, Tim. Torified wood is being marketed for outdoor use pretty heavily by one of my suppliers and it would be interesting to see how you make out.