Tom Buck on sun 26 may 02
John Christie:
You ask about the water-gas reaction. My take, for what it is
worth, follows:
1) It is, in practical terms, impossible to combust totally a
fossil fuel on first attempt, ie, have the air/fuel ratio precisely that
which is needed to convert all hydrocarbon or carbon to H2O and CO2, or
CO2 alone. Especially in a potter's kiln where "dwell time" is quite
brief. Some carbon particles will surely always be present in the kiln
gases.
2) The water-gas reaction occurs whether you want it or do not
want it. Without preconditioning (as in industry) raw air always contains
some moisture.
3) The main point being discussed in this thread started by
Clennell is: how much extra reduction does the water-gas reaction produce
on a rainy day?
The answer cited by experienced potters: on a rainy day, pots
undergoing reduction in the kiln always show an improved glaze response,
both in colour and surface.
and 4) Can this result be achieved via water injection? While the
answer is yes, I doubt if any Clayarter has devised a controlled method of
moisturizing incoming raw air, and whether the added cost (and risk of
failure to control properly) is justified by the often slight improvement
in the appearance of pots.
Perhaps there is a curious potter among us who would undertake a
project to determine whether moisturizing is feasible and economic.
til later. Peace. Tom B.
Tom Buck ) -- primary address. "alias"
or secondary address.
tel: 905-389-2339 (westend Lake Ontario, province of Ontario, Canada).
mailing address: 373 East 43rd Street, Hamilton ON L8T 3E1 Canada
Lee Love on mon 27 may 02
Getting good carbon trapping related to rainy days may have nothing to
do
with moisture aiding the reduction firing. What I have noticed, is that
my
shinos dry more slowly when I glaze on a wet day (I have often glazed and
put
things immediately into the kiln.) If the pots are still damp in the
kiln,
the candling dries them very quickly. I am not positive, but I am
guessing
that quick drying of the wet glaze helps pull the soluables to the surface
of
the glaze.
--
Lee In Mashiko, Japan Ikiru@hachiko.com
"We can only wait here, where we are in the world, obedient to its
processes,
patient in its taking away, faithful to its returns. And as much as we may
know, and all that we deserve of earthly paradise will come to us."
Wendell Berry , Full Quote: http://www1.ocn.ne.jp/~ikiru/berry.html
Paul Herman on mon 27 may 02
Tom,
Have you seen the "Ceramics Technical" article by Owen Rye? He is
exploring water and fire stuff, going so far as to build a kiln with
perforated water pipes under the floor. Also Richard Bresnahan in
Minnesota adds water during firing. They both get very nice results.
Best wishes,
Hardway Herman
Tom wrote:
and 4) Can this result be achieved via water injection? While the
> answer is yes, I doubt if any Clayarter has devised a controlled method of
> moisturizing incoming raw air, and whether the added cost (and risk of
> failure to control properly) is justified by the often slight improvement
> in the appearance of pots.
> Perhaps there is a curious potter among us who would undertake a
> project to determine whether moisturizing is feasible and economic.
> til later. Peace. Tom B.
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