A local wood trader has shown me some thermally modifid ash planks (never seen that before!) with a stunning coloring that almost seduced me to immediately buy a table and two benches worth of it and build some new massive garden furniture.
Now, the wood is thermally modified. Which basically means it went into a kiln at a somewhat higher temperature and underwent a heat-induced chemical reaction. I had never seen such a wood (if you can still call it that) before. It's apparently a rather new thing (less than 20 years old) too.
From what I could gather from various (partially contradicting) sources, this means:
- Greatly improved resistance to fungi and parasites, suitable for outdoor
- Even woods like beech and oregon pine are resistance class 1-2 after treatment
- Best invention since the invention of the wheel
- Wood almost doesn't work any more (50-75% reduction in shrinkage/growth, nearly no water uptake)
- No treatment needed
- Treatment recommended (... OK?)
- Varnish needed, oiling before varnish recommended to give the wood back its elasticity (how would that work???)
- Insufficient data for close-to-earth placement, might not be good (WTF?)
- Darker color (very obvious, and good looking, main reason to buy!)
- Harder, but somewhat more brittle
- Need to pre-drill big screws (Wow, I wouldn't have guessed that!)
- Not recommended to have too sharp edges in the open (Again, wow, what an insight!)
- Slightly less stable (slightly? how much?), not suitable for construction (why not, if it's just slightly weaker?)
- Glue might take up to 10 times as long to dry (... but, will it hold?)
So, what does that mean in summary? And does one of you maybe have experience working with that and can confirm or deny any of the above?
For example, when someone tells me "hard and brittle", I come to think of mineral substances. As in, giving that ultra-fine dust that causes lung cancer when being worked. Not exactly what I'd like.
When someone tells me "controlled, partial combustion, chemical change", I come to think of "easily flammable" and "unknown evaporations".
Are there some obvious and maybe not-so-obvious reasons why one wouldn't want to use such a kind of wood?