Thermally Modified Lumber

[landlocked sailor]

I recently came across this stuff at my local lumber yard. Does anybody here have experience with the stuff? It sure sounds like a viable (though expensive) alternative to PT stuff with potential marine applications. Rick

[Nicholas Carey]

I don't know about thermally treated lumber, but I just ran across this today: Titanwood Accoya (http://www.titanwood.com/home.html).

It's seems interesting. I was looking for decking (not that kind, the other kind...on the house).

Accoya is "acetylated lumber". The deal is that wood contains free hydroxyl groups. Treating/Reacting the wood with acetyl anhydride (acetylation) converts the free hydroxyls to acetyl groups:

http://www.titanwood.com/images/stories/technology_formula.jpg

The free hydroxyl groups are what adsorb water. Conversion to acetyl groups stops that, thus making the wood more stable. Also claimed is that decay fungi start their work at the hydroxyl sites, again, the claim is that decay fungi no longer recognize the wood as food following acetylation.

Evidently, wood technologists have been looking at this for 75 years.

The claims are improved durability, hardness, dimensional stability, UV resistance. More at http://sierrafp.com/

[David G]

I recently came across this stuff at my local lumber yard. Does anybody here have experience with the stuff? It sure sounds like a viable (though expensive) alternative to PT stuff with potential marine applications. Rick

This is a new one to me also. Do you have more details, or a link, or a company name/trade name that we could research?

[Timo_N62.9_E27.7]

Are you talking about this stuff?

http://www.lunawood.fi/index.php?l=5

If I remember right the wood hardens and loses some of its elasticity which might be a problem in structural members of a boat.

Maybe for laying a deck?

[Bruce Hooke]

This page is instructive: http://www.lunawood.fi/index.php?sivu=179&p=174&l=5

Note that in the list of properties it says "Possesses the desired strength," which I read to mean that it possess enough strength for the intended uses, which appear to be mostly for things where strength is not the most important issue. It would be great to see some actual test data for the wood so that it could be compared with untreated wood, but lacking that my suspicion is that it should not be used in places where strength is critical, which rules it out for many boat parts.

[Timo_N62.9_E27.7]

Actually they recommend it for decks like I quessed:D

http://www.lunawood.fi/index.php?sivu=188&p=185&l=5

[Bruce Hooke]

They also say it can be used for structural components so the key would be to see the actual strength data.

[Timo_N62.9_E27.7]

Another manufacturer says:

"ThermoWood is slightly more fragile and dryer than normal wood, so risk of tearing has grown a bit when processing the wood in horizontal direction."

http://www.suomenlampopuu.fi/in_english/info_about_thermowood/

[landlocked sailor]

Probably nice for outdoor projects; arbors, furniture, gates. Stuff like that. Rick Aaargh

[Bruce Hooke]

I note this line as well from the link Timo posted:


The ThermoWood process can reduce splitting strength of the wood. The use of self-tapping screws or pre-drilling of holes must be made to avoid cracking of the material. It is recommended to use low threaded screws.

Clearly the process does have an impact on the strength of the wood...

[Paul Girouard]

We're looking at using some Radio Frequency dried timbers for some corbels here real soon. I got the pricing on Friday I need to do the extension to get a accurate cost difference between the RF timbers and "normal" KD D. Fir FOHC beam stock.

All rough sawn stock , 6 by material mainly.

They say less checking , splitting , twisting, etc.

[Paul Girouard]

Here's a link to the RF site:

http://harvest-timber.blogspot.com/

[resolute56]

Thermally modified wood is being produced in Kingston, NH. Please see www.cambiawood.com.

[Mrleft8]

Another direction on "modified" wood... WWW.Flutedbeams.com

[Paul Pless]

If I remember right the wood hardens and loses some of its elasticity which might be a problem in structural members of a boat. 'loses some of its elasticity', eh? probably also means its gonna be tougher to bend... not many straight lines on a boat...

[CapnJ2ds]

If I hadn't read all the above, I'da hassumed that "thermally modified lumber" was what you raked out of the ash box of your wood-burner stove.

[SMARTINSEN]

I have heard it called "Torrfied" wood.

Around here we can get Torrefied poplar sold as decking. 1" x 5-1/4" for $2.98/lf.

Even though it is poplar, it has a dark brown hue that makes it look very much like walnut. I have never used it, but am considering doing so, perhaps some porch furniture.

Does anyone have any actual experience with thermal treated wood?