terry sullivan on tue 15 jul 03
Mel San has said it. We have a lot to learn, or unlearn. Most of us are
firing based on handed down methods from folks who know how to make some
glaze firing produce the result but it isn't based on science. It's
based on techniques developed over decades , or even centuries, of
empirical expirience.
It works but it isn't necesssarily the most efficient way.
At Pasadena Community College, led by Phill Cornelius, I had the
opportunity to take over the glaze firing of all student work for a year
when Phill was on sabatical for a year. I had several years expirience
with the kilns and the suite of glazes and had been taught the
"classic" firing schedual: candle overnight, start the glaze firing in
the morning at about 300 deg. f., bring it to about cone 1 for a "body"
reduction, then fire neutral to cone 10 and reduce again for the glaze.
Then shut the kiln off after a half hour soak and close the sucker up to
cool. When done with a bit of expirience and artistry, the glazes all
came out fine.
At the same time I was also a geology major with some chemistry as
well. My work in geology in the Petrology classes, that's the formation
of crystaline formations in magma mixes, I sensed something wrong with
what I was told in the ceramics classes.
It just didn't "jive" with the science. So one day I decided to take a
chance and fast fire a load of work. Went from cold to cone 10 in
about 4 hours in a west coast 30 cu. ft. kiln. Then did the reduction
and held the kiln in neutral to mild reduction on the way down and
closed the kiln to cool. What happened ? All the glazes came out great
! and the clay bodies were well reduced to toasty brown. So much for
the accepted method. I never persued that beyond that period, but it
did indicate that it is the down side that is important.
Terry Sullivan
Nottingham Arts
mel jacobson on tue 15 jul 03
please note:
i am not a ceramic engineer, chemist, or such,
i am a potter. i talk to folks, like to know what
is going on.
there seems to be strong evidence that slow, careful
glaze firing...taking hours and hours is a bit meaningless.
more happens to glazes in the cooling cycle than
in the firing cycle.
i am finding that to be the truth.
a great deal of mis/information has been given
to potters over the years.
industry and engineering are debunking that myth
very fast.
industry is firing glazed ware in 20 minutes.
very dry pots are run through the cycle as fast
as they can go.
i realize that is not our ntent, and it sure is not my
intent.....i want to be prudent. but, wasting gobs
of fuel, firing for hour after hour on low settings
and soaking kilns at the wrong temp is stupid. it just
wastes time and fuel. the pots do not give a damn.
i just like a bit of evidence that it means something.
hank has done a great deal of research, others, nils and
more....and all come to the conclusion that we are
not doing good science with all the soaking at high
temp.
reds, shino, copper...all need special handling...and
it is a must...so, the fire down method works for that.
other glazes like temmoku, celedon do not work well
with that method...so, we change.
one size does not fit all.
it has always been that way.
we need to do a great deal of work yet.
we are not even close to understanding what
is going on.
so, we work.
and study...and share.
mel
From:
Minnetonka, Minnesota, U.S.A.
web site: my.pclink.com/~melpots
or try: http://www.pclink.com/melpots
new/ http://www.TICK-ATTACK.COM
Joe Coniglio on tue 15 jul 03
I've often thought 7-14 days of amagama to reach ^10-11 seems a bit excessive
considering the unpredictable results.
Stoneware tableware manufacturers definitely don't have long run times. How
about those sink and toilet makers running their stuff through a furnace
conveyor as long as a football field, continuously loading and unloading?
Interested in what the fast fire leaders of the group think about what's
going on with firing today. There are also the single fire folks.
Paul Herman on tue 15 jul 03
Hi Joe,
In my short experience, time seems to have a remarkable effect on firing
with wood. Slow firing makes more colors, more intensely. Fourteen days
seems a bit much for my taste, but it has gone three, and I'd like to
try four.
If you fire an Anagama, unpredictable results can be the best part.
People strive for them. It requires a change in thinking, though. You've
got to let go of some of the desire for security, and embrace
serendipity. If predictable results are desired, gas kilns are good. But
then after a while, predictable results can get kinda tired, and well,
boring. Living on the edge has it's rewards.
Just another view of time....
best wishes,
Paul Herman
Great Basin Pottery
423-725 Scott Road
Doyle, California 96109 US
potter@psln.com
----------
>From: Joe Coniglio
>To: CLAYART@LSV.CERAMICS.ORG
>Subject: Re: slow firing/fast fire
>Date: Tue, Jul 15, 2003, 2:11 PM
>
> I've often thought 7-14 days of amagama to reach ^10-11 seems a bit excessive
> considering the unpredictable results.
Sue Leabu on wed 16 jul 03
On Tue, 15 Jul 2003 17:11:15 -0400, Joe Coniglio
wrote:
>I've often thought 7-14 days of amagama to reach ^10-11 seems a bit
excessive considering the unpredictable results.
Hi Joe,
For me, the unpredictable nature is a big part of the attraction and magic
of the Anagama. That, and the results are not like any other firing
method,is what has kept me going for 3 years, 8 firings.
It doesn't have to take 7 or 14 days to reach temp. I've fired the same
Anagama (450 cf) for 3-1/2 days, 5 and 8 days. We could probably get to
temp in 2 days, maybe less, if we wanted to. Have never wanted to, although
I think I'd like to try a 10 or 12 day firing sometime. :o)
One of the main reasons for prolonging the firing is to allow more ash to
accumulate on the pots which will become the glaze when it melts. Flame
markings and coal pile fuming are also quite different when the firing is
longer, which means a richer colors and more dramatic effects.
To fire an anagama, one really gives over their pots to the firing process
(and the kiln gods) to provide the decoration. The loss rate can be
significant, and it's physically taxing, but when the results are good,
it's really worth it.
Sue in Kalamazoo, MI
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