Subject: [baidarka] ammonia bending?
From: Rob Macks (robm@shaysnet.com)
Date: Sat Mar 09 2002 - 09:41:09 EST
Bruce Hoadley, professor of wood technology, at U Mass Amherst covers
the subject of bending with ammonia in his book "Understanding Wood".
He says, "ammonia interacts with the lignin as well as the cellulosic
portion of the cell-wall structure."
He states," Two basic systems have been developed; immersion in liquid
anhydrous ammonia at atmospheric pressure, and treatment with gaseous
anhydrous ammonia in closed chambers at 145 psi pressure.
(Household ammonia, commonly used for cleaning, is a water solution of
ammonia and useless in plasticizing wood)."
He further states, "With the liquid immersion process, heavy duty
refrigeration equipment is required to keep the ammonia below its
boiling point of -28°."
The fumes produced and equipment required are beyond most small shops' budgets.
So whatever luck you have in bending soaked wood has nothing to do with
the household ammonia you're using.
All the best,
Rob Macks
Laughing Loon CC&K
"Anderson, Gregory [MCCUS]" wrote:
>
> "The second rib bent well by soaking in the ammonia solution only
> for 48
> hours (i.e. without the water "pre-soak" for 48 hours)."
>
> Yes. I soaked rib only the ammonia solution for 48hrs and bending went well.
>
> The ammonia was the cheapest store brand they had...$1.69 for 2 quarts. It
> was "clear" so there were no added dyes or scents..
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