Alan Carruth wrote:
A bit of caution might be in order. All the thermally modified wood I've seen has had much different properties than non-modified stock. In particular, it tends to be very prone to splitting. That may not be as much of a problem on a fingerboard, but I also wonder about the surface hardness over the long term.
Well, I have worked with at least 30 species of thermally modified wood, and I have not seen a problem. Surface hardness does not seem to be an issue, and I cannot imagine how that would change "over the long term".
I am at the point that, unless somebody specifically insists on it, I do not even use non-thermally modified wood except for linings, bindings, and other minor trim (rosette, etc.). The increased resonance, and much increased stability, I see as major plusses (and it looks better, too).
As for stability, I can give you a non-lutherie example: I built a 2" thick, 33" wide door, solid wood, edge glued the whole width, 190C thermally modified monkeypod. It has been installed in a below grade setting that, over the past year has been through a cycle of several episodes of a flooded floor to relative humidity of below 15%. During this time the actual width of the door has fluctuated only 1/16 inch. I would not even have thought about building such a door, given the setting, from non-thermally modified wood...just would not have worked.
I will agree that thermally modified (torrefied) wood is a different animal, and there are things we still need to learn, but, so far, I see mostly positive differences over non-TM.
FWIW
Obviously, there are many opinions
Grant