
New process for preserving lumber could offer advantages over pressure treating - elijahparker
https://phys.org/news/2020-02-lumber-advantages-pressure.html
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0134340
One advantage they don't discuss is perhaps lack of toxicity. I used to do
Carpentry during summer break and sometimes we'd burn scraps for heat. I was
advised not to throw treated lumber into the pile as it's toxic so this would
be a good step in the right direction towards less toxins introduced into
homes and groundwater.

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djaychela
Agreed, but looking at the three substances they mention in the article -
Oxides of Zinc, Aluminium and Titanium, I guess there could be other
considerations in terms of groundwater issues?

Also, how practical, cost-wise would this be? It's not mentioned in the
article, but surely titanium would be prohibitive in terms of cost? (Even for
small amounts)

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IanCal
Let's see if I can multiply up the numbers correctly. Please let me know if
I'm messing these up.

Article is closed, but supplementary material is free.

Each experiment is 3 blocks of wood, each 5 grams. So 15g of wood.

They say they need 2x10^20 molecules of TiCl4 for one experiment (perhaps the
final deposited amount in the extreme 'all cells covered' case). Or 3x10^-4
moles. That's 200x10^-4 or 2x10^-2 for 1kg wood. Making it up to 1 mole gives
us 50kg of wood. 1 mole is 190g of TiCl4. Or about 250kg wood per kg TiCl4.

Alibaba costs (I'm not in the field so that's based on it being there first
link) puts that at maybe a dollar or two.

Caveats: may require less because completely covering all cells is not
realistic. May require more because you don't use things completely
efficiently. Alibaba may not be representative (either direction) and the
"99.9%" pure stuff there may not be good enough and going higher may get
exponentially more expensive.

But it doesn't seem like the raw cost of the materials _necessarily_ would be
a problem to me.

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bitslayer
The article is credited "by Georgia Institute of Technology", so it is a press
release. This is just early research, but presumably the problems of toxicity
are what inspired the study in the first place. But, they can't make any
claims yet, because lawyers. And cost would be a huge factor, unless
regulation were involved. There is a potential public good in reducing toxins
in the environment. But what about their idea of using it for framing lumber?
Nobody uses pressure treated for framing today, do they? It would help
insulate, they say, but there's no way that would make any sense unless the
cost were much lower than today's treated lumber, which... well it's just an
early research project.

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sidewndr46
The thing about toxins in treated lumber, it isn't a bug in the product. It is
actually the feature. Treated lumber is just as porous and traps water like
any other lumber. It has so much copper compounds trapped in it that almost
nothing can ever break it down. If you bury treated lumber in the ground you
will find it sterilizes a small layer of soil around it. This is why it is so
effective.

Anything trying to reduce the toxicity of treated lumber by swapping on a
coating runs into the same problem as traditional methods like painting the
lumber: a single tiny hole in the coating allows the entire piece of lumber to
be compromised.

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Olreich
Why are all of the comparisons to untreated lumber? Shouldn’t they have tested
against pressure-treated lumber too to see how well it performs against that?

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horsawlarway
I'm not familiar with all types, but most pressure treatments don't attempt to
stop water uptake, they just impregnate the wood with pesticides/fungicides.

It's not there to stop the water, it's there to stop termites, fungi, mites
and other pests that can degrade or threaten the integrity of wood. That's why
most exterior decking should be sitting on something like this
([https://www.amazon.com/Simpson-Strong-Tie-
ABA44Z-Gauge-20-Pa...](https://www.amazon.com/Simpson-Strong-Tie-
ABA44Z-Gauge-20-Pack/dp/B002LOT0TA?ref_=fsclp_pl_dp_5)) to prevent water
uptake.

I'd be curious to see how this compares to treated wood for their mold test,
though. That seems like a really valid test.

