David Cuzick on thu 30 aug 07
Vince, The soft brick I was referring to are in Ruthann Tudball's kiln in England. She told me that her kiln was holding up well to the soda firings. I will be there in a couple of weeks and plan to see her and I will find out more about these brick and how they are working. I also saw a high alumina hard brick kiln at the studio of Cynthia Bringle , a catinary arch kiln, although used many times the brick showed no sign of any soda buildup on the walls. They were absolutely dry and clean. This was a couple of years ago, I'd be curious to see how the kiln is holding up.
I used a good grade dense hard brick in my soda kiln (with soft brick exterior) and have fired it about thirty times. I have lots of soda glaze build up on the walls but the kiln is in very good condition. The walls are beautiful...I'd like to have a pot so good looking. The plans for this kiln are on our website at cuzickpottery.com. It is a copy of the kiln use at SDSU. I think the most interesting thing is the use of six small venturi burners to fire the kiln (about 50 cubic feet total interior space) . In theory not nearly enough btu's to fire the thing. I took the orifice out of the burners so there is about a 1/4" hole for the gas to go through. I used a very large (1.5") pipe manifold to the burners and rather low pressure. It fires beautifully to cone 10 without using excess gas.This is a very cheap and efficient burner system. I guess it is a low pressure high volume set up. It is very important to note that this is done with natural gas...do not try it with
high pressure liquid gas!
David Cuzick in San Diego
Eric Suchman wrote: 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.
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Lee Love on fri 31 aug 07
On 8/31/07, June Perry wrote:
> Ruthanne Tudball in recent years has been spraying the soda solution. She
> has a new kiln now which is a combination gas and wood and she's still spraying
> the soda in solution. She's also making a paste of it and spreading that on
> wood before introducing the wood.
You are right. The firing I was thinking about, that was at her web
site, was someone else's kiln. She was doing a workshop.
Euan introduces soda by sandwiching paste between two flat boards.
> She covers her technique for introducing soda on her website:
> _www.ruthannetudball.com_ (http://www.ruthannetudball.com)
She sprays into the fireboxes, which should protect the
bricks more than spraying into the ware chamber.
--
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
Lee Love on fri 31 aug 07
On 8/31/07, David Cuzick wrote:
> Vince, The soft brick I was referring to are in Ruthann Tudball's kiln in England. She told
>me that her kiln was holding up well to the soda firings.
David,
I believe the method of introducing soda, along with what
kind of soda, will determine the ware it inflicts on softbrick.
I met Ruthann about 6 years ago when she visited Mashiko.
She uses the French salt method of placing many cups filled with soda
though out the kiln. This really helps keep the soda localized and
away from the kiln walls.
Use only glazed cups because soda can eat through a porous,
unglazed clay body.
--
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/
Pat Southwood on fri 31 aug 07
Hi David,
I am about an hours drive from Ruthanne, (just round the bypass, she knows
me. )
Its a pity you wernt here last week, we had the Anglian Potters summer camp,
a firing extravaganza, to say the least, even for an old pyromaniac like
myself.
If you fancy another workshop to look around (not soda firing tho' -
recycling Norfolk thatching reed that has come off of old houses
hereabouts.)- in the middle of the very picturesque Norfolk Broads and
merely yards away from a major award winning real ale brewery do get in
touch.
Pat Southwood
pat@southwood4.fsnet.co.uk
----- Original Message -----
From: "David Cuzick"
To:
Sent: Friday, August 31, 2007 7:22 AM
Subject: Re: soda kiln brick, was soda kiln wash
> Vince, The soft brick I was referring to are in Ruthann Tudball's kiln in
> England. She told me that her kiln was holding up well to the soda
> firings. I will be there in a couple of weeks and plan to see her and I
> will find out more about these brick and how they are working. I also saw
> a high alumina hard brick kiln at the studio of Cynthia Bringle , a
> catinary arch kiln, although used many times the brick showed no sign of
> any soda buildup on the walls. They were absolutely dry and clean. This
> was a couple of years ago, I'd be curious to see how the kiln is holding
> up.
> I used a good grade dense hard brick in my soda kiln (with soft brick
> exterior) and have fired it about thirty times. I have lots of soda glaze
> build up on the walls but the kiln is in very good condition. The walls
> are beautiful...I'd like to have a pot so good looking. The plans for this
> kiln are on our website at cuzickpottery.com. It is a copy of the kiln use
> at SDSU. I think the most interesting thing is the use of six small
> venturi burners to fire the kiln (about 50 cubic feet total interior
> space) . In theory not nearly enough btu's to fire the thing. I took the
> orifice out of the burners so there is about a 1/4" hole for the gas to go
> through. I used a very large (1.5") pipe manifold to the burners and
> rather low pressure. It fires beautifully to cone 10 without using excess
> gas.This is a very cheap and efficient burner system. I guess it is a low
> pressure high volume set up. It is very important to note that this is
> done with natural gas...do not try it with
> high pressure liquid gas!
> David Cuzick in San Diego
>
> Eric Suchman wrote: 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.
>
> ______________________________________________________________________________
> 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.
>
>
>
> ---------------------------------
> Shape Yahoo! in your own image. Join our Network Research Panel today!
>
> ______________________________________________________________________________
> Send postings to clayart@lsv.ceramics.org
>
> You may look at the archives for the list or change your subscription
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>
> Moderator of the list is Mel Jacobson who may be reached at
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>
>
June Perry on fri 31 aug 07
Ruthanne Tudball in recent years has been spraying the soda solution. She
has a new kiln now which is a combination gas and wood and she's still spraying
the soda in solution. She's also making a paste of it and spreading that on
wood before introducing the wood.
There are pictures of her new kiln but they're so tiny, I can't see whether
they're hard or soft brick or a combination and she doesn't give that
information.
She covers her technique for introducing soda on her website:
_www.ruthannetudball.com_ (http://www.ruthannetudball.com)
Regards,
June
_http://www.shambhalapottery.com_ (http://www.shambhalapottery.com)
http://shambhalapottery.blogspot.com/
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Vince Pitelka on fri 31 aug 07
David Cuzick wrote:
> Vince, The soft brick I was referring to are in Ruthann Tudball's kiln in
> England. She told me that her kiln was holding up well to the soda
> firings. I will be there in a couple of weeks and plan to see her and I
> will find out more about these brick and how they are working. I also saw
> a high alumina hard brick kiln at the studio of Cynthia Bringle , a
> catinary arch kiln, although used many times the brick showed no sign of
> any soda buildup on the walls. They were absolutely dry and clean. This
> was a couple of years ago, I'd be curious to see how the kiln is holding
> up.
David -
Thanks for all that good information. I'd love to learn more about this,
and will look forward to hearing more about Ruthann's kiln. Also, as I
mentioned in my previous post, it is apparent that there are many variations
of high-alumina brick. I expect that in industry, even high-alumina brick
can be fired so high as to vitrify, in which case the sodium could not
penetrate the brick. Perhaps Cynthis Bringle was fortunate enough to obtain
some of that brick. And even with porous high-alumina brick like the ones
that went bad in our salt kiln, perhaps a surface sealant would have greatly
prolonged the life of the kiln.
Several years ago when we were discussing the possibility of softbrick soda
kilns, someone mentioned a kiln owned by a famous potter (I can't remember
who it was) who finally had to rebuild her softbrick soda kiln after ten
years of use. That seemed like a very long time for a softbrick
vapor-glazing kiln, but then it came out that in that time she had fired the
kiln only about 100 times. If one considers 100 firings a long life for a
kiln, then fine, but several years ago when we had a number of advanced
students doing soda firing, we were doing about 75 firings a year. and thus
got only a few years out of that kiln. So you can see why we switched back
to hardbrick. I'd love to be able to have a softbrick soda kiln.
Lee Love made a very good point about Ruthann's method of introducing the
soda with cups of soda distributed throughout the set. It seems that this
approach gives much more localized soda deposition directly in the vicinity
of the ware. With that approach, I can see how the whole kiln doesn't get
nearly as saturated with soda. I'm going to try that in upcoming soda
firings. I was wondering about the amount of soda, but I suppose if you
just put in plenty, and include lots of draw rings, you could just fire
until you get the surfaces you want, and then crash the kiln to low red heat
to stop the deposition. Do you know if Ruthann does that? Otherwise I
would think it would be difficult to gauge the amount of soda deposition.
Perhaps it doesn't matter as much on her beautiful pots, but I use intricate
inlaid colored clay patterns, and too much soda deposition makes the inlays
start to run on the surface. With way too much soda, it completely blurs
the patterns.
I just did a cone 6 soda firing on a load of pots coated with several
different terra sigs. I unload it tomorrow. This is experimental. I am
hoping that the soda will have partially eaten through the terra sig in
spots or specks over the surfaces. We'll see how it turns 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/
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