I.Lewis on thu 7 oct 99
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My experience of this is limited and occurred many years ago. I was firing a
cross draft hard brick kiln with diesel fuel and oil coke would build up in =
the
fire mouths. A steel rod was used to thump the coke loose and rather than =
rake
it out I prayed it when it became red hot with mist from a garden sprayer. =
This
seemed to cause it to burn away. The old chemistry book gave the answer. I
always found that when I had done this, glazes seemed to be brighter and
attributed this to the possibility of higher flame temperatures of burning
hydrogen.
Earlier this year I looked at a site on the net of a Finnish potter. He had
built a Water-gama, an anagama style kiln which had a shallow trough down =
the
centre of the chamber along which it seemed water could be flooded. Very
impressive pictures. How successful it was I would not know. Can=92t find =
the URL
in my records but I think I got to it through links with Dragon Lady in BC.
I see steam injection as a way of increasing heat potential and of getting =
rid
of charcoal build up but the reactions will only occur above about 1100degC.=
The
reaction is endothermic and a blast of air is needed to reheat the charcoal =
or
coke as it cools down. Industrially the reaction is made self sustaining by
using a metered flow of steam and air and the product is called Producer =
Gas.
Producer gas trailer units were used in England during WW2 to supply fuel =
for
public omnibuses when gasoline (petrol/essence) was unobtainable.
There is an interesting discussion of the effects of water in wood in An =
Artists
Guide to Firing Kilns by Harry Memmott printed by Victoria College, Prahran
Campus in Australia. He developed this book from his lecture notes after
teaching kiln management at the Ceramics Dept. of Prahran College.
I hope this information satisfies and helps those who are curious about =
water or
steam injection. I have always noticed that I get better results from my gas
fired kiln when atmospheric humidity is high and try to fire on such days, =
rare
though they are in this part of South Oz.
Regards to all.
Ivor Lewis.
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