Eric Suchman on mon 27 aug 07
Hi All,
I'm considering spraying the soft brick of my kiln with a solution
of 50% alumina hydrate and 50% epk. My idea is to protect the soft
brick from the effects of salt and or soda vapours. Do you think
that this solution will stick without flaking off or stay on and help
protect the bricks?
Any other thoughts?
Thanks,
Eric in Oceanside
James and Sherron Bowen on tue 28 aug 07
You guys are neighbors. You should get together.
JB
----- Original Message -----
From: "David Cuzick"
To:
Sent: Tuesday, August 28, 2007 6:48 PM
Subject: Re: soda Kiln Wash
> Eric, the solution that you describe will stick to the brick initially,
> but will rapidly deteriorate and flake off causing more problems than it
> will solve. It will be especially problematic if you use it on the top of
> the kiln where it can flake off and fall into pots. I have found that the
> ITC ceramic coating that was so widely touted a couple of years ago will
> also flake off after three or four firings using soda or salt. Years ago i
> repaired the back wall of a salt/soda kiln with soft brick and even though
> the brick did deteriorate and glass over they lasted a long time.
> I have heard of high alumina soft brick that will hold up to soda or salt.
> Those brick were from England and I have no source for them.
> David Cuzick
> in San Diego
>
> Eric Suchman wrote: Hi All,
> I'm considering spraying the soft brick of my kiln with a solution
> of 50% alumina hydrate and 50% epk. My idea is to protect the soft
> brick from the effects of salt and or soda vapours. Do you think
> that this solution will stick without flaking off or stay on and help
> protect the bricks?
> Any other thoughts?
> Thanks,
> Eric in Oceanside
>
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David Cuzick on tue 28 aug 07
Eric, the solution that you describe will stick to the brick initially, but will rapidly deteriorate and flake off causing more problems than it will solve. It will be especially problematic if you use it on the top of the kiln where it can flake off and fall into pots. I have found that the ITC ceramic coating that was so widely touted a couple of years ago will also flake off after three or four firings using soda or salt. Years ago i repaired the back wall of a salt/soda kiln with soft brick and even though the brick did deteriorate and glass over they lasted a long time.
I have heard of high alumina soft brick that will hold up to soda or salt. Those brick were from England and I have no source for them.
David Cuzick
in San Diego
Eric Suchman wrote: Hi All,
I'm considering spraying the soft brick of my kiln with a solution
of 50% alumina hydrate and 50% epk. My idea is to protect the soft
brick from the effects of salt and or soda vapours. Do you think
that this solution will stick without flaking off or stay on and help
protect the bricks?
Any other thoughts?
Thanks,
Eric in Oceanside
______________________________________________________________________________
Send postings to clayart@lsv.ceramics.org
You may look at the archives for the list or change your subscription
settings from http://www.ceramics.org/clayart/
Moderator of the list is Mel Jacobson who may be reached at melpots@pclink.com.
---------------------------------
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Vince Pitelka on wed 29 aug 07
David Cuzick wrote:
> I have heard of high alumina soft brick that will hold up to soda or salt.
David -
I suppose that there is a broad range of different high alumina brick for
different applications. About ten years ago the big APGreen plant in
Bessemer, AL was bought out by Harbison-Walker, who already had a plant
nearby, so they were just sutting down the APGreen plant. We were able to
go down there with a TTU dumptruck and get many thousands of free brand new
brick. Most of them were Kruzite high-alumina brick used in the steel
industry.
We built a 60 cu. ft. salt kiln and a 200 cu. ft. "hoggama" hybrid
groundhog/anagama. The latter is still in excellent condition. The former
lasted only about three years. Granted, we do a lot of salt firing, but the
problem is that the porous high-alumina brick admitted sodium vapors, which
solidified inside the brick and over time caused it to expand and spall. It
was truly terrible to see what happened to that kiln over such a short
period of time. We expected it to be resistant to salt, the way an
alumina/china clay shelf wash shows no effect of the salt. We failed to
consider that the sodium fumes could penetrate the porous brick and condense
inside, causing the brick to expand over time fairly quickly.
I would be wary of high-alumina brick in a salt kiln, unless it is a type
that has been proven to work well over time, or unless the interior surface
is thoroughly sealed. . A salt kiln built of good standard high-duty
firebrick like APGreen Clippers or Empires with a coat of shino glaze on the
inside will last for a very long time under normal use. That's what we have
now, and it is on it's fifth year with a few years to go. My students do a
lot of salt firing.
- Vince
Vince Pitelka
Appalachian Center for Craft, Tennessee Technological University
Smithville TN 37166, 615/597-6801 x111
vpitelka@dtccom.net, wpitelka@tntech.edu
http://iweb.tntech.edu/wpitelka/
http://www.tntech.edu/craftcenter/
Vince Pitelka on thu 30 aug 07
> Could I put a coat of shino on soft brick to seal it?
There is nothing I know of that will protect soft brick in a salt or soda
kiln, but I guess that depends on how often you fire. We fire a lot, and we
tried everything on soft brick before we switched back to hardbrick soda
kilns. If you do decide to try a shino coating on soft brick, please let us
know how it works out.
- Vince
Vince Pitelka
Appalachian Center for Craft, Tennessee Technological University
Smithville TN 37166, 615/597-6801 x111
vpitelka@dtccom.net, wpitelka@tntech.edu
http://iweb.tntech.edu/wpitelka/
http://www.tntech.edu/craftcenter/
Eric Suchman on thu 30 aug 07
Could I put a coat of shino on soft brick to seal it?
-Eric
On Aug 29, 2007, at 6:40 PM, Vince Pitelka wrote:
> David Cuzick wrote:
>> I have heard of high alumina soft brick that will hold up to soda
>> or salt.
>
> David -
> I suppose that there is a broad range of different high alumina
> brick for
> different applications. About ten years ago the big APGreen plant in
> Bessemer, AL was bought out by Harbison-Walker, who already had a
> plant
> nearby, so they were just sutting down the APGreen plant. We were
> able to
> go down there with a TTU dumptruck and get many thousands of free
> brand new
> brick. Most of them were Kruzite high-alumina brick used in the steel
> industry.
>
> We built a 60 cu. ft. salt kiln and a 200 cu. ft. "hoggama" hybrid
> groundhog/anagama. The latter is still in excellent condition.
> The former
> lasted only about three years. Granted, we do a lot of salt
> firing, but the
> problem is that the porous high-alumina brick admitted sodium
> vapors, which
> solidified inside the brick and over time caused it to expand and
> spall. It
> was truly terrible to see what happened to that kiln over such a short
> period of time. We expected it to be resistant to salt, the way an
> alumina/china clay shelf wash shows no effect of the salt. We
> failed to
> consider that the sodium fumes could penetrate the porous brick and
> condense
> inside, causing the brick to expand over time fairly quickly.
>
> I would be wary of high-alumina brick in a salt kiln, unless it is
> a type
> that has been proven to work well over time, or unless the interior
> surface
> is thoroughly sealed. . A salt kiln built of good standard high-duty
> firebrick like APGreen Clippers or Empires with a coat of shino
> glaze on the
> inside will last for a very long time under normal use. That's
> what we have
> now, and it is on it's fifth year with a few years to go. My
> students do a
> lot of salt firing.
> - Vince
>
> Vince Pitelka
> Appalachian Center for Craft, Tennessee Technological University
> Smithville TN 37166, 615/597-6801 x111
> vpitelka@dtccom.net, wpitelka@tntech.edu
> http://iweb.tntech.edu/wpitelka/
> http://www.tntech.edu/craftcenter/
>
> ______________________________________________________________________
> ________
> Send postings to clayart@lsv.ceramics.org
>
> You may look at the archives for the list or change your subscription
> settings from http://www.ceramics.org/clayart/
>
> Moderator of the list is Mel Jacobson who may be reached at
> melpots@pclink.com.
Thomas Ladd on thu 30 aug 07
Eric,
The thing to understand about applying coatings to the surface of soft brick
kilns in particular is that any layer applied to the interior surface of the
kiln adheres to the surface over time as the soda is a flux. This surface
layer has a different coefficient of expansion from the underlying brick.
Soft brick is inherently weak and over time the difference in expansion
between the surface layer and the underlying brick will cause the surface to
spall off. Different soft bricks will react differently and over the first
10 or 15 firings surface applications seem to work. In my experience and
testing in quite a few kilns and over 400 firings I've found the easiest and
best results from leaving the bricks alone, knocking spalling off only when
it gets bad, stuffing major cracks with fiber, and loading with shelves over
the top layer of pots to catch anything falling from the roof.
Tom Ladd
Lee Love on thu 30 aug 07
Look in the archives. The mat coatings do little to protect
softbrick. I believe there is a Donovan recipe for a shino glaze he
has had some luck with on softbrick. The glass surface seals the
porous softbrick. I also posted links to a study done by an Irish
potter on coatings from CT. He found a glass like coating from a
glass company in England.
In my wood kiln that is lined with softbrick, the worst wear
is where I put too thick a coat of 50/50 as you ask about. It all
spalled off. The thinner coat wears a little better.
--
Lee in Minneapolis, Minnesota USA
"Making pots should not be a struggle.
It should be like walking down a hill
in a gentle breeze." --Shoji Hamada
http://mashikopots.blogspot.com/
"For a democracy of excellence, the goal is not to reduce things to a
common denominator but to raise things to a shared worth."
--Paolo Soleri
Ivor and Olive Lewis on sat 1 sep 07
Dear Eric Suchman,
From time to time this idea is proposed but in my opinion it fraught =
with danger.
Although we fire glaze batch materials to high temperatures to melt =
them, the glaze which forms in this process of vitrification has a =
remelt temperature that is much lower. The Expansivity charts in =
Mastering Cone 6 glazes show this is in the region of about 700 deg C =
for Cone 6 glazes.
Shino Glaze will melt and cause corrosion of your brickwork. This may be =
slow to begin with but as Soda dissolves in the molten lining the =
process will accelerate.
If you know someone with a suitable kiln make a sample coated brick and =
test it over about twenty firings.
Best regards,
Ivor Lewis.
Redhill,
South Australia.
Lee Love on sat 1 sep 07
Another post I found related to Meanly article. I would highly
recommend the article.
> A glass barrier seals the brick and keeps the vapor from
> attacking it. He briefly mentions coating soft brick with shino
> glaze. He did tests with a commercial glass barrier coat from
> Scotland that he tested in over 500 firings with some success. It is
> used in the glass making industry. I was in contact with the
> company, but while the coating is cheap, the shipping costs were
> prohibitive so I dropped that Idea. I think it ships in liquid form.
>
> See the original article:
>
> Peter Meanly in Ceramics TECHNICAL periodical #18 2004
--
Lee in Minneapolis, Minnesota USA
"Making pots should not be a struggle.
It should be like walking down a hill
in a gentle breeze." --Shoji Hamada
http://mashikopots.blogspot.com/
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