My steam bending chamber (3-inch steel pipe x 60 inches long with 1500 watt
electric heater in one end) 3/4 full of water, quickly comes up to the
pressure switch set point of 10 psi, and has worked ok for some years,
usually bending hickory for Windsor chair backs. Now, when I try to use it
on white oak, the wood has a nasty black color. Why?
One theory has something to do with the tannic acid I believe is present in
the oak, but I'm no chemist. Is there a reaction between the steel pipe and
the oak? Any comments are welcome. Dave
David Anderson asks:
>My steam bending chamber (3-inch steel pipe x 60 inches long with 1500 watt
>electric heater in one end) 3/4 full of water, quickly comes up to the
>pressure switch set point of 10 psi, and has worked ok for some years,
>usually bending hickory for Windsor chair backs. Now, when I try to use it
>on white oak, the wood has a nasty black color. Why?
>One theory has something to do with the tannic acid I believe is present in
>the oak, but I'm no chemist. Is there a reaction between the steel pipe and
>the oak?
It's not a theory, it's a fact. You need another steam bending chamber of a
material other than steel or iron.
Charlie Self
"The test and the use of man's education is that he finds pleasure in the
exercise of his mind." Jacques Barzun
On Wed, 02 Jun 2004 12:31:42 -0400, Jay Pique <[email protected]>
wrote:
>Me neither, but from what I understand some people actually use vinegar with
>iron soaked in it to "ebonize" their oak.
In past times, Japanese women used this same preparation to blacken
their teeth for cosmetic reasons.
(And before we feel too smug, European women of the same period were
using white lead as a skin foundation)
>> Is there a reaction between the steel pipe and the oak?
You bet there is !
> Any comments are welcome.
Plastic gas main pipe for oak. Less risk of burning yourself when
handling it too. I've also never needed to pressurise a steam chamber.
--
Smert' spamionam
"David Anderson" <[email protected]> wrote
>My steam bending chamber (3-inch steel pipe x 60 inches long with 1500 watt
>electric heater in one end) 3/4 full of water, quickly comes up to the
>pressure switch set point of 10 psi, and has worked ok for some years,
>usually bending hickory for Windsor chair backs. Now, when I try to use it
>on white oak, the wood has a nasty black color. Why?
Tannic acid present in the oak is reacting with the iron in the steel.
>One theory has something to do with the tannic acid I believe is present in
>the oak, but I'm no chemist.
Me neither, but from what I understand some people actually use vinegar with
iron soaked in it to "ebonize" their oak.
> Is there a reaction between the steel pipe and the oak? Any comments are welcome. Dave
Try googling a bit on "ebonize or ebonizing, oak, vinegar, tannic acid, etc..."
JP