thacker@island.net on thu 4 apr 96
Fellow CLAYART-ers,
I have just fired a brand new 30 cubic foot
Estrin front loading kiln. The problem I have is that
it takes too long to cool. (6 hours to fire 18+ hours to cool)
I would like to be able to fire and cool to re-loading temp at
least every 12 hours (2 firings/day).
There are no peepholes in the kiln, should I put some in and
use these to help in the cooling process? Is there a method for
figuring out where to place these peepholes and what size?
Thanx in advance,
Robin B. Thacker
Fine Art Productions
Vancouver Island, B.C.
Karl David Knudson on fri 5 apr 96
On Thu, 4 Apr 1996 thacker@island.net wrote:
> ----------------------------Original message----------------------------
> I have just fired a brand new 30 cubic foot
> Estrin front loading kiln. The problem I have is that
> it takes too long to cool. (6 hours to fire 18+ hours to cool)
> I would like to be able to fire and cool to re-loading temp at
> least every 12 hours (2 firings/day).
What temperature are you firing to? ^10? If so I don't think that you
can cool it in 6 hours unless you fire the kiln nearly empty because of
the amount of thermal mass inside the kiln.
Two suggestions:
1. fire to a lower temp.
2. Force cool.
The fastest I've found to cool a kiln is to open the door. If you're
really sure that you need to cool the kiln really fast this might be the
only way do do so. Unfortunately, your loss rate will climb to near
100% depemding upon your clay body. It's also a fire hazard and not a
very healthy thing to walk in front of. Anyone know about kiln stress? A
less destructive (and dangerous) way would be to leave the damper wide
open. Less destructive than that would be to leave the damper open initially
until the kiln cools to what 1100 F or so and then close it.
Another good way to make shards...
Karl
Eugene, OR
SLPBM@cc.usu.edu on tue 9 apr 96
Karl's responce reminds me of a c/10 raku firing process we used to do
back at UMASS when no one was looking. Great way to singe a great portion of
hair off your body. Be smart and wear protective gear and respect the heat.
Alex Solla
slpbm@cc.usu.edu
bburruss@csn.net on wed 10 apr 96
>----------------------------Original message----------------------------
>
>Karl's responce reminds me of a c/10 raku firing process we used to do
>back at UMASS when no one was looking. Great way to singe a great portion of
>hair off your body. Be smart and wear protective gear and respect the heat.
>
>Alex Solla
Alex,
Are you willing to elaborate on c/10 raku? I've got a colleague
with c/10 gas fired salt kiln willing to try.
Thanks,
Bob Burruss . . . always interested in raku experiments
in Conifer, CO, but traveling to Williamsburg, VA and Anchorage, AK
in the next two weeks and firing in between.
SLPBM@cc.usu.edu on wed 10 apr 96
About this idea of c/10 raku... much of what I know of it comes from trying
to understand Japanese Seto (black) wares. I had seen some pictures in books
and was curious how the effect worked.... had done raku a few time and
simply gave it a try. Process is exactly like raku only hotter and the clay
needs to be rather open. The idea as I understand it is to reduce the kiln
throughout the firing as one would with a reduction firing, then at c/10
pull the pots and then allow them to cool naturally. Some will undoubtably
crack or worse, but hey, this is an experiment right!??
Currently I am toying with the idea of c/6-8 reduction cooled pots which are
crash cooled to seal in the reduction. ie the door is opened at c/8 then
the pyrometer is watched till the kiln hits 1450^F or so, then clammed shut
to cool slowly. I will post results as soon as some arrive.
Best of luck to anyone pushing the fire.
Alex Solla
slpbm@cc.usu.edu
Karl David Knudson on thu 11 apr 96
On Wed, 10 Apr 1996 my buddy Alex wrote:
> ----------------------------Original message----------------------------
> Process is exactly like raku only hotter and the clay needs to be
> rather open.
There is an article in CM about a potter doing ^10 salt raku or something
similar he had a clay body recipe that he used as well as glazes that
worked. I don't remember though if this article was in a recent CM or
an old one as I've been wading through the last 30 years worth of
backissues as well as the current issues.
> Currently I am toying with the idea of c/6-8 reduction cooled pots which are
> crash cooled to seal in the reduction. ie the door is opened at c/8 then
> the pyrometer is watched till the kiln hits 1450^F or so, then clammed shut
> to cool slowly. I will post results as soon as some arrive.
I tried something similar with a friend last summer experimenting with
copper reds. The colors were a bit brighter from the fast cooling
process, but using a grolleg porcelain body was even more effective for
brightening the reds. We cooled using the damper and the blowers on the
powerburners, cooling from ^9 to touch temperature in about 2 hours,
slowing only for quartz inversion.
SIDE STORY: The best piece we had was one that my
partner pulled out of the kiln with tongs at about 700F. He set it
down on the floor and we all crowded around to marvel at the beautiful
red. Far and away the most beautiful copper red in the universe. Just
as we we (about 5 of us) were about to come to blows about who should
get to keep this gift from the kiln gods, the piece, sensing out plight,
proceded to dunt itself into enough pieces to that we all could have a
piece of its glory. I currently carry my shard around in a small ark I
constructed for it.
Karl in Eugene, where you can tell when soccer season starts because it
gets really cold and rainy.
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