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of base kiln shelves and firebrick support under them

updated thu 13 jan 11

 

DJ Brewer on sun 9 jan 11


I have a full shelf for the bottom shelf of my Skutt 1027 Kilnmaster.
It is NOT 1 inch thick (not sure of the thickness -- but its damn
heavy). I've fired it to cone 10 twice before I heard from a friend
that its too thin to take a cone 10 firing. They say it will slump
sooner or later.

My question is -- if I support it underneath with a lot of firebricks (I
have a ton of them from a kiln I have not built yet) -- will the shelf
still slump? I don't want to have to buy another base kiln shelf for my
cone 10 firings if I don't have to.

thanks for any and all responses

DJ

John Rodgers on sun 9 jan 11


A big factor here it the material the shelf is made of. That is
critical. I've seen 2 inch mullite shelves bend at cone 10 or better.
Yet Crystar and Advancer shelves are thin and will not bend. Plenty of
support underneath will prevent that bending, but then if you do that -
you have basically defeated the purpose of just using a shelf. You may
as well Layer the bottom with the bricks and set the pots there. But
make sure your shelf is of an appropriate material for the heat range.

John Rodgers
Clayartist and Moldmaker
88'GL VW Bus Driver
Chelsea, AL
Http://www.moldhaus.com


On 1/9/2011 5:40 PM, DJ Brewer wrote:
> I have a full shelf for the bottom shelf of my Skutt 1027 Kilnmaster.
> It is NOT 1 inch thick (not sure of the thickness -- but its damn
> heavy). I've fired it to cone 10 twice before I heard from a friend
> that its too thin to take a cone 10 firing. They say it will slump
> sooner or later.
>
> My question is -- if I support it underneath with a lot of firebricks (I
> have a ton of them from a kiln I have not built yet) -- will the shelf
> still slump? I don't want to have to buy another base kiln shelf for my
> cone 10 firings if I don't have to.
>
> thanks for any and all responses
>
> DJ
>
>

Paul Herman on sun 9 jan 11


DJ,

Sure, put a lot of props under the shelf and it won't be as likely to
sag. Use light weight props if possible, and just prop it up an inch
or even half inch. Heavy ones will use more KW to fire the kiln.

good firings,

Paul Herman

Great Basin Pottery
Doyle, California US
www.greatbasinpottery.com/




On Jan 9, 2011, at 3:40 PM, DJ Brewer wrote:

> I have a full shelf for the bottom shelf of my Skutt 1027 Kilnmaster.
> It is NOT 1 inch thick (not sure of the thickness -- but its damn
> heavy). I've fired it to cone 10 twice before I heard from a friend
> that its too thin to take a cone 10 firing. They say it will slump
> sooner or later.
>
> My question is -- if I support it underneath with a lot of
> firebricks (I
> have a ton of them from a kiln I have not built yet) -- will the shelf
> still slump? I don't want to have to buy another base kiln shelf for
> my
> cone 10 firings if I don't have to.
>
> thanks for any and all responses
>
> DJ

Arnold Howard on wed 12 jan 11


On 1/9/2011 5:40 PM, DJ Brewer wrote:
> My question is -- if I support it underneath with a lot of firebricks (I
> have a ton of them from a kiln I have not built yet) -- will the shelf
> still slump?

DJ, supporting the bottom shelf with firebricks may not be feasible.
Whole bricks, which are large thermal masses, could change the heating
characteristics of your kiln. You could slice them into smaller pieces,
but it would be easier to use short posts. You can evenly distribute
several under the shelf.

Sincerely,

Arnold Howard
Paragon Industries, L.P., Mesquite, Texas USA
ahoward@paragonweb.com / www.paragonweb.com

James Freeman on wed 12 jan 11


DJ...

At the college, the bottom shelves are supported on a bunch of small pieces
of old, broken kiln shelf, perhaps a dozen or so bits per kiln, perhaps an
inch or so square.

At my home studio, the bottom shelf in my large kiln is held up with a half
a dozen or so pieces of 1 1/8" kiln shelf, the corners sawn from some 24"
square shelves in order to make them into octagons. These pieces are
carefully placed in between the floor elements so as not to cover them. Th=
e
bottom shelf in my small kiln is held up by a few 1/2" commercial kiln
posts. I recently sawed some 1/2" shelves for my raku kiln out of some old=
,
broken half-rounds, so I will probably replace the 1/2" posts with bits of
the shelf scrap.

Just some ideas.

All the best.

...James

James Freeman

"...outsider artists, caught in the bog of their own consciousness, too
preciously idiosyncratic to be taken seriously."

"All I say is by way of discourse, and nothing by way of advice. I should
not speak so boldly if it were my due to be believed."
-Michel de Montaigne

http://www.jamesfreemanstudio.com
http://www.flickr.com/photos/jamesfreemanstudio/
http://www.jamesfreemanstudio.com/resources



On Sun, Jan 9, 2011 at 6:40 PM, DJ Brewer wrote:

> I have a full shelf for the bottom shelf of my Skutt 1027 Kilnmaster.
> It is NOT 1 inch thick (not sure of the thickness -- but its damn
> heavy). I've fired it to cone 10 twice before I heard from a friend
> that its too thin to take a cone 10 firing. They say it will slump
> sooner or later.
>
> My question is -- if I support it underneath with a lot of firebricks (I
> have a ton of them from a kiln I have not built yet) -- will the shelf
> still slump? I don't want to have to buy another base kiln shelf for my
> cone 10 firings if I don't have to.
>
> thanks for any and all responses
>
> DJ
>

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