Glenn Dair on fri 7 oct 05
We're about to build a cross-draft soda kiln, interior 3x3x4, and I'm =
looking for feedback on details. This is the first soda, but not the =
first kiln I've built. I have plans for a hard-brick liner, soft-brick =
outer. Has anyone had success (long-term) with an all soft-brick soda =
kiln? I've seen massive spalling due to the attempt to ITC protect soft =
brick, and don't want to go that way. I prefer to build for the long =
run, spend time making pots, instead of rebuilding kilns.
Vince Pitelka on sat 8 oct 05
> What does anyone think of lining an IFB wall with 1" cordierite shelving
> for
> soda?
Betsy -
I can't see any way you would attach it. Expansion and contraction would
cause it to work loose very soon, and that would make a real mess.
Cordierite is basically the same composition as hard brick, and so if you
want that kind of interior, you might as well just build a kiln with an
inside layer of hardbrick and an outside layer of IFB.
Best wishes -
- 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/
Hank Murrow on sat 8 oct 05
On Oct 7, 2005, at 6:46 PM, Glenn Dair wrote:
> We're about to build a cross-draft soda kiln, interior 3x3x4, and I'm
> looking for feedback on details. This is the first soda, but not the
> first kiln I've built. I have plans for a hard-brick liner, soft-brick
> outer. Has anyone had success (long-term) with an all soft-brick soda
> kiln? I've seen massive spalling due to the attempt to ITC protect
> soft brick, and don't want to go that way. I prefer to build for the
> long run, spend time making pots, instead of rebuilding kilns.
Ask Vince Pitelka about his soda kiln. It seemed sensible to me.
Cheers, Hank
www.murrow.biz/hank
Vince Pitelka on sat 8 oct 05
Glenn Dair wrote:
"We're about to build a cross-draft soda kiln, interior 3x3x4, and I'm
looking for feedback on details. This is the first soda, but not the first
kiln I've built. I have plans for a hard-brick liner, soft-brick outer. Has
anyone had success (long-term) with an all soft-brick soda kiln? I've seen
massive spalling due to the attempt to ITC protect soft brick, and don't
want to go that way. I prefer to build for the long run, spend time making
pots, instead of rebuilding kilns."
Glen -
Our soda kiln is a 20-cubic (overall volume) cross-draft. It gets used very
heavily - probably twice a week on the average, so that's about 100 firings
per year. We have to do extensive repair or rebuild about once every three
to five years, and thus over time have done considerable experimentation. I
have always used hardbrick on the high-stress areas - firebox, burner ports,
bag wall, flue, door sills, door, and have experimented with IFB elsewhere
in the kiln. On the hotface surfaces that are IFB, we have used a thin
saturating spray coat of ITC 100, and that has definitely helped to protect
the IFB. But those are still the first areas to go, thus the periodic
repair/rebuild.
Our current soda kiln has hardbrick inside extending about 2/3 up the walls
at the firebox end, stepping down diagonally towards the flue end, and the
arch is all IFB. The chimney is all hardbrick. The floor is built up on a
single layer of cinderblock with a layer of cement board on top, two layers
of scrap IFB, and then a hotface floor of new hardbrick. We built this kiln
last year very late in the budget year, and our budget was about gone. I
did some research, and a certain much-appreciated and honorable Georgia
supplier of bargain refractories recommended a mortar which could be thinned
and sprayed on in place of ITC. We took his advice, and now, seven months
later, the lining is already peeling off. We are going to have to grind it
down and then spray on the ITC that we should have used to begin with. If
you are going to use any IFB on the inside, spray it with a thin saturating
coat of ITC 100.
Building a fuel efficient kiln is the responsible thing to do, especially
with rapidly-rising natural gas and propane prices. A kiln that is 60% IFB
on the inside will probably result in at 30% to 40% reduction in fuel costs
over one with an all-hardrick liner, which will amount to a lot of money
over time. You say that you want to build for the long-run, spending the
time making pots rather than rebuilding kilns. I can certainly respect
that, but once you build the kiln with a sturdy welded steel frame around
it, when it comes time to rebuild it, you simply dismantle the damaged
portions of the kiln and rebuild them within that steel frame. Your
burners, floor, and chimney will most likely all be reusable, along with
portions of the lower walls, so it really is not much work to rebuild the
high-stress parts of the kiln. Many of the bricks will be reuseable. The
rebuild would probably require $500 worth of brick and ITC, and it would be
a one-day project. Bear in mind that our kiln gets used 100 times a year,
and we have to do at least a partial rebuild every three to five years.
That's 300 to 500 firings in the life of a soda kiln, which isn't bad at
all. How often do you plan to fire this kiln? If the kiln is fired once a
week, which is still a lot, it might last six to ten years before needing
serious repair/rebuild.
One final point - how heavily do like to charge the soda? We usually charge
from one to two pounds of soda in a 20 cubic foot kiln, going for fairly
light soda effects with lots of glazed surfaces on the pots, and that
certainly contributes to the life of the kiln. Some of the most influential
soda potters like Julia Galloway and Jeff Oestreich do a light soda effect
on glazed ware, and those soda kilns suffer relatively little deterioration
over time. If you are planning to do that kind of firing, then I would
definitely go for a mostly IFB liner as described above.
It sounds like you might want to just build our kiln. Come up and take a
look at it.
Good luck -
- 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/
John Baymore on sat 8 oct 05
Glenn,
Hi.
Simple "truth"................ soda eats up insulating firebrick. The
fast lining deterioration is a "cost of doing business" if you make the
decision to use IFB for the lining for some reason. There could be
reasons... but you have to know that going in in order to weigh the
decisions well.
The best IFB for soda use, in my experience, appears to be from Thermal
Ceramics.
I have used ITC to SLOW the deterioration. It does. It does not stop it.
And you have to apply it to brand new bricks prepared exactly the way
specified. Most people don;t clean the surface correctly before applying
and then put it on too thick ....the "more is better" syndrome .
But it does not slow it by all that much, in my experience. And if you
put the ITC on too thick... yes... it causes massive spalling.
You are absolutely correct in the obesrvation about "building kilns"
versus making pots. THAT is a cost of replacing/re-lining a kiln that
most potters tend to overlook. When you are a kiln builder.... you are
not a potter. Yet one more "timeframe" factor that needs to be figured
into the pricing of your work .
So... if structural longevity is the goal for you... you'd best line with
hardbrick or a hard castable for soda use.
best,
..................john
John Baymore
River Bend Pottery
22 Riverbend Way
Wilton, NH 03086 USA
JBaymore@compuserve.com
http://www.JohnBaymore.com
"Please use compuserve address for any direct communications."
Mark Knott on sat 8 oct 05
I built a soda kiln last year and after much consideration went with a hardbrick inside and softbrick outside. The reason for me is simply, the risk/reward of spending the money on softbrick and the itc 100 coating was too great with such mixed results from so many differant potters. As john b. posted earlier my research found that the decieding factor in choosing IFB and itc is being sure that your IFB will hold up. IFB vary from co. to co. I felt that for the amount of firings I do per year, 12 - 15, hardbrick was the way to go for me. The possibility of having to rebuild or repair the kiln in due to flaking/spauling is real if the wrong softbricks are chosen. I got this information from other potters accross the country that have used both building methods. Even with the increased fuel cost the hardbrick kiln serves my needs as one of my tools, and should last for many years. Just my thoughts. mark knott
Betsy Levine on sat 8 oct 05
What does anyone think of lining an IFB wall with 1" cordierite shelving for
soda?
Betsy
-----Original Message-----
From: Clayart [mailto:CLAYART@LSV.CERAMICS.ORG]On Behalf Of Mark Knott
Sent: Saturday, October 08, 2005 4:49 PM
To: CLAYART@LSV.CERAMICS.ORG
Subject: soda kiln design
I built a soda kiln last year and after much consideration went with a
hardbrick inside and softbrick outside. The reason for me is simply, the
risk/reward of spending the money on softbrick and the itc 100 coating was
too great with such mixed results from so many differant potters. As john b.
posted earlier my research found that the decieding factor in choosing IFB
and itc is being sure that your IFB will hold up. IFB vary from co. to co. I
felt that for the amount of firings I do per year, 12 - 15, hardbrick was
the way to go for me. The possibility of having to rebuild or repair the
kiln in due to flaking/spauling is real if the wrong softbricks are chosen.
I got this information from other potters accross the country that have used
both building methods. Even with the increased fuel cost the hardbrick kiln
serves my needs as one of my tools, and should last for many years. Just my
thoughts. mark knott
____________________________________________________________________________
__
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You may look at the archives for the list or change your subscription
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Wayne on sat 8 oct 05
I'm wondering about using some of that kaowool sheet Mel spoke of
recently, soaking it with ITC and pinning it to the kiln
floor/wall/ceiling as it's built. Seems that as a sacrificial
layer, it would go far to saving the brick in a soda/salt scenario.
Certainly cheaper than a rebuild.
Thoughts?
Wayne Seidl
-----Original Message-----
From: Clayart [mailto:CLAYART@LSV.CERAMICS.ORG] On Behalf Of Betsy
Levine
Sent: Saturday, October 08, 2005 9:14 PM
To: CLAYART@LSV.CERAMICS.ORG
Subject: Re: soda kiln design
What does anyone think of lining an IFB wall with 1" cordierite
shelving for
soda?
Betsy
-----Original Message-----
From: Clayart [mailto:CLAYART@LSV.CERAMICS.ORG]On Behalf Of Mark
Knott
Sent: Saturday, October 08, 2005 4:49 PM
To: CLAYART@LSV.CERAMICS.ORG
Subject: soda kiln design
I built a soda kiln last year and after much consideration went with
a
hardbrick inside and softbrick outside. The reason for me is simply,
the
risk/reward of spending the money on softbrick and the itc 100
coating was
too great with such mixed results from so many differant potters. As
john b.
posted earlier my research found that the decieding factor in
choosing IFB
and itc is being sure that your IFB will hold up. IFB vary from co.
to co. I
felt that for the amount of firings I do per year, 12 - 15,
hardbrick was
the way to go for me. The possibility of having to rebuild or repair
the
kiln in due to flaking/spauling is real if the wrong softbricks are
chosen.
I got this information from other potters accross the country that
have used
both building methods. Even with the increased fuel cost the
hardbrick kiln
serves my needs as one of my tools, and should last for many years.
Just my
thoughts. mark knott
____________________________________________________________________
________
__
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.
Ivor and Olive Lewis on sun 9 oct 05
Dear Betsy Levine=20
You ask <cordierite shelving for
soda?
As an alumino silicate refractory Cordierite should resist the ravages =
of hot soda but it would probably give no better protection than high =
alumina firebrick, which would be far less expensive.
You are also left with a couple of engineering problems. How to cement =
the shelves to your IFB and how to protect the roof. Interesting work =
devising adhesives for these tasks!!!
My own preference, which I used when firing in the traditional style =
with Sodium Chloride, is to use high alumina dense firebrick and coat =
this with alumina-kaolin wash.
Best regards,
Ivor Lewis.
Redhill,
S. Australia.
Glenn Dair on mon 10 oct 05
Wayne's wondering about using a fiberboard liner reminds me of a story =
that my brick-supplier told me years ago. Their main business is =
industrial furnaces, and one of their big customers was a company on the =
eastern shore which processes raw clams into those yummy clam-strips. =
(apologies to all you vegans). They were using what was essentially a =
large open-ended shuttle-kiln, similar to what toilets and bricks are =
fired in. 2400 F in the hot zone. They would run the shuttles through =
pretty fast, loaded with unshucked clams, and when those little guys hit =
the "hot zone", they'd just open right up and be perfectly steamed. The =
kiln was lined with fiber-board, and all the brine resulted in the same =
as in a salt-kiln. A whold lot of dead fiber board. They were making =
enough money off the clams to have the kiln re-lined once a year. =
Another reason to be making (and selling) those $600 teapots.
Thanks for all the responses about the kiln construction. The students =
are going to be helping, so now I guess the big thing will be to slow =
them down enough to keep the rows level.
Glenn Dair/ Callanwolde/ Atlanta
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