Andrew M Casto on tue 7 feb 06
=3D2>Hello all, I have a question regarding=
using castable in kiln I am thinking of building. I have obtained 2 skids =
of wescolite insulating 2600 degree castable. I have used some of it in var=
ious exterior locations on the wood kiln we presently fire, and it seems to=
hold up well in this application. I would like to build a gas (propane) ki=
ln in the near future to do cone 10 reduction...somewhere in the range of 5=
0-70 cubic feet, softbrick construction...possibly flat top, possibly sprun=
g arch (not sure yet). My understanding is that "insulating" castables=
, as opposed to "dense" are better used on cold faces of kilns as back up i=
nsulation...I have checked out Olsen and he seems to confirm this. I would =
like to save myself some cash on softbrick when I build, and I was wonderin=
g if it would follow use 4.5 inches of ifb in the walls of the kiln, and th=
en another 4.5 of castable backing this up. If this would work, would the b=
est idea be to create "forms" of sorts to mould the castable? I was thinkin=
g I could build the forms out of plywood for the floor and exteri=
or walls. Once these set, I was imagining dry-laying the Ifb=
inside them. I would then add the flat top, or the arch as the case might =
be. My concerns are about the loadbearing position of the side walls with t=
he castable (would it crack and crumble eventually?), and if perhaps I shou=
ld use steel rod or rebar as reinforcements inside the castable. =
I have also read Nils' comment in CM this month...he =
suggests 4.5 inches of brick in walls. Do folks agree with this? And, =
maybe a related question...is the castable more trouble than it's worth? Wo=
uld it just make more sense to buy the extra IFB and save the castable for =
something else? Or on the contrary, would the castable be sufficient f=
or hot face use, and could a whole kiln be built from it? (I'm guessing no,=
but I thought it was worth throwing out there). >Thanks in advance for your advice.
Andy Casto IV>www.redbridge=
pottery.com =
Ann Brink on tue 7 feb 06
Hello Lee,
The door panels are about 9" thick. They don't weigh much. My mixture had
a lot of vermiculite in it. I went and looked in my records and found that
the mixture I used was:
1 part (by volume) Lumnite refractory cement
1 part fireclay
3 parts vermiculite.
I also found my photocopy of Lowell Baker's article (CM Nov. 1981) and see
that he has aabout 10 recipes in it. I remember telephoning him for
guidance before choosing a recipe and somehow got the impression that
there's a wide latitude in what will work for this sort of thing, as long as
it's got something to make it set, something to stick it together, and
something for a filler as insulation, it will pretty much work. The recipe
I just gave was not actually inthe article ...can't say now how I came up
with it. It's light, fairly soft, and did shrink some on the hot face.
Insulated really well.
About the buttons holding the refractory fiber onto the ceiling- I was
mistaken in my description earlier...I actually made sort of golf tee
looking things with the hole in the tip--that way the nichrome wire was
several inches away from the hot face. I did this after first making simple
buttons with wire going through them- the wire gave way in the first firing.
Ann Brink in Lompoc CA
----- Original Message -----
From: "Lee Love"
> On 2006/02/08 1:43:20, annsart@impulse.net wrote:
> > Hello Andrew,
> >
> > My updraft gas kiln has a hardbrick floor and castable walls and roof.
> > Picture of it is at http://members.impulse.net/~annsart/gasfiring.html
> > The castable was from a recipe in CM by Lowell Baker, about 20 years
> ago.
> > It handles cone 10 just fine, but soon developed cracks on the inside
> face
> > (shrinkage), and the ceiling was shedding crumbs, so a few years ago I
> > lined the top with refractory fiber, attached with fireclay buttons
> > wrapped with fiber.
>
> Your door is very interesting. How thick are the panels and how much do
> they weigh? Bricking up my door takes far too long. Anybody got Lowell's
> castible recipe handy? For a burnout filler, I will probably use rice
> husks instead of sawdust.
>
> Also, your fiber covering is something I have wondered could be done to
> protect the inside of a softbrick salt or wood kiln. Using board, fiber
> blanket or tile. Something light might be best on the arch.
>
steve graber on tue 7 feb 06
i do. i made a 70 cubic foot kiln, arch downdraft, and used one layer of K23's for the bulk of the kiln. over this i added *fluffy cement* which was around half & half saw dust & cement (maybe 2 to 3 inches). the final layer was regular cement for weather protection. one day for apearance i want to add a surface of granite stones because we have so many around the area. a cobblestone kiln will simply look cool.
at cone 10 i can lay on the outside of the kiln & feel a very nice warmth. CERTAINLY not going to burn me if i fall on it & i didn't spend extra cash on more bricks or further layers of cement stuff...
up until the lastest price jump in natural gas i was seeing about a $45 firing cost. i'll be firing again in a few weeks & will note what today's fee is.
see ya
steve
"I have also read Nils' comment in CM this month...he suggests 4.5 inches of brick in walls. Do folks agree with this? "
Andrew M Casto wrote:
Hello all,
I have a question regarding using castable in kiln I am thinking of building. I have obtained 2 skids of wescolite insulating 2600 degree castable. I have used some of it in various exterior locations on the wood kiln we presently fire, and it seems to hold up well in this application. I would like to build a gas (propane) kiln in the near future to do cone 10 reduction...somewhere in the range of 50-70 cubic feet, softbrick construction...possibly flat top, possibly sprung arch (not sure yet). My understanding is that "insulating" castables, as opposed to "dense" are better used on cold faces of kilns as back up insulation...I have checked out Olsen and he seems to confirm this. I would like to save myself some cash on softbrick when I build, and I was wondering if it would follow use 4.5 inches of ifb in the walls of the kiln, and then another 4.5 of castable backing this up. If this would work, would the best idea be to create "forms" of sorts to mould the castable? I was
thinking I could build the forms out of plywood for the floor and exterior walls. Once these set, I was imagining dry-laying the Ifb inside them. I would then add the flat top, or the arch as the case might be. My concerns are about the loadbearing position of the side walls with the castable (would it crack and crumble eventually?), and if perhaps I should use steel rod or rebar as reinforcements inside the castable.
I have also read Nils' comment in CM this month...he suggests 4.5 inches of brick in walls. Do folks agree with this? And, maybe a related question...is the castable more trouble than it's worth? Would it just make more sense to buy the extra IFB and save the castable for something else? Or on the contrary, would the castable be sufficient for hot face use, and could a whole kiln be built from it? (I'm guessing no, but I thought it was worth throwing out there).
Thanks in advance for your advice.
Andy Casto
www.redbridgepottery.com
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Ann Brink on tue 7 feb 06
Hello Andrew,
My updraft gas kiln has a hardbrick floor and castable walls and roof. =
Picture of it is at http://members.impulse.net/~annsart/gasfiring.html =
The castable was from a recipe in CM by Lowell Baker, about 20 years =
ago. It handles cone 10 just fine, but soon developed cracks on the =
inside face (shrinkage), and the ceiling was shedding crumbs, so a few =
years ago I lined the top with refractory fiber, attached with fireclay =
buttons wrapped with fiber. That fixed it. (I've fired it only seldom =
the last few years, using my electric kiln instead) I also made the =
door blocks, casting them in a form on the driveway.
The castable was a 2nd attempt for this kiln; first we used a hard brick =
interior with outer bricks of diatomateous earth (local product from the =
mines here) and installed a sheet metal shell on the outside. The roof =
had been a flat-top incorrectly done which failed. So we dismantled it, =
leaving the floor and sheet metal. I built a plywood box and packed the =
castable between it and the sheet metal. About 9 inches thick. After =
that was set up we built a curved form and did the roof.
When I fire, I usually stack up some hard bricks next to the side walls; =
I like the extra heat retention.=20
It's possible that the commercial castable wouldn't develop cracks.
Good luck!
Ann Brink in Lompoc CA
The constru
----- Original Message -----=20
From: Andrew M Casto=20
I have a question regarding using castable in kiln I am thinking of =
building. I have obtained 2 skids of wescolite insulating 2600 degree =
castable. ....(more)
Lee Love on wed 8 feb 06
On 2006/02/08 1:43:20, annsart@impulse.net wrote:
> Hello Andrew,
>
> My updraft gas kiln has a hardbrick floor and castable walls and roof.
> Picture of it is at http://members.impulse.net/~annsart/gasfiring.html
> The castable was from a recipe in CM by Lowell Baker, about 20 years
ago.
> It handles cone 10 just fine, but soon developed cracks on the inside
face
> (shrinkage), and the ceiling was shedding crumbs, so a few years ago I
> lined the top with refractory fiber, attached with fireclay buttons
> wrapped with fiber.
Your door is very interesting. How thick are the panels and how much do
they weigh? Bricking up my door takes far too long. Anybody got Lowell's
castible recipe handy? For a burnout filler, I will probably use rice
husks instead of sawdust.
Also, your fiber covering is something I have wondered could be done to
protect the inside of a softbrick salt or wood kiln. Using board, fiber
blanket or tile. Something light might be best on the arch.
THanks!
--
李 Lee Love 大
愛 鱗
in Mashiko, Japan http://mashiko.org
http://seisokuro.blogspot.com/ My Photo Logs
http://ikiru.blogspot.com/ Zen and Craft
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