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## kiln wall thickness?

### Larry Kruzan on wed 15 oct 08

Hi All,

=20

My existing 100 c.f. kiln has 9=94 IFB walls as did most other kilns I =
have
fired. Most (not all) of the commercial built small gas kilns seem to =
have
4 =BD=94 walls, some with fiber back-up, some without anything else. I =
have
scratched my head at this difference while looking at some of these =
kilns
and wondered how well they held up after many firings.

=20

Now I=92m planning to build a new gas test kiln with a stacking space of =
20
c.f. or so. Three 12x24 shelves wide and 3 =BD foot tall area. Given =
this
small footprint I think that one row of bricks is structurally strong =
enough
but I wonder about how it will handle the heat. Looking at Nils Lou=92s =
book
=93The Art of Firing=94 I see many kilns with single brick walls.

=20

So I would like to ask all our great kiln builders what would you do and
why?

=20

Thanks,

Larry Kruzan

Lost Creek Pottery

www.lostcreekpottery.com

=20

### Monica Wright on thu 16 oct 08

In grad school I was taught that the standard 9 inch thickness is for no ot=
her reason than structural stability.=A0 If you pull a brick out of you kil=
n wall when it is around 2300 degrees you will only have red heat penetrati=
ng 2 inches or so on the brick.=A0 Really you only need a little more than =
that... at least that is how=A0I was taught.=A0 Makes sense to me.
=A0
-Steve

--- On Wed, 10/15/08, Larry Kruzan wrote:

From: Larry Kruzan
Subject: Kiln Wall Thickness?
To: CLAYART@LSV.CERAMICS.ORG
Date: Wednesday, October 15, 2008, 10:13 PM

Hi All,

=20

My existing 100 c.f. kiln has 9=94 IFB walls as did most other kilns I ha=
ve
fired. Most (not all) of the commercial built small gas kilns seem to have
4 =BD=94 walls, some with fiber back-up, some without anything else. I hav=
e
scratched my head at this difference while looking at some of these kilns
and wondered how well they held up after many firings.

=20

Now I=92m planning to build a new gas test kiln with a stacking space of 20
c.f. or so. Three 12x24 shelves wide and 3 =BD foot tall area. Given this
small footprint I think that one row of bricks is structurally strong enoug=
h
but I wonder about how it will handle the heat. Looking at Nils Lou=92s bo=
ok
=93The Art of Firing=94 I see many kilns with single brick walls.

=20

So I would like to ask all our great kiln builders what would you do and
why?

=20

Thanks,

Larry Kruzan

Lost Creek Pottery

www.lostcreekpottery.com

=20

### William Perrine on thu 16 oct 08

I built a 24c.f. wood fire kiln with 4 1/2" wall thickness with a canternary=
arch design and it was "ok" structurally but a lot better with a refractory=
mix over wire mesh.=C2=A0 I used 6 parts vermiculite/coarse sawdust, 2 part=
s fire clay, 2 parts silica sand (60 mesh) and 1 part portland cement. It en=
ded up being 3" thick. Not only did it stabilize the kiln a lot but I had mu=
ch better temperature retention and slower cooling.=C2=A0 When I tried it wi=
th just the bricks, I had a tough time getting it hot enough and cooling slo=
w enough. I like to use micro crystaline glazes and shinos which do better w=
ith slow cooling, for me. Thanks to John Thies' design ( manabigama) in Cera=
mics Monthly a few months ago. I guess it depends on loading room, (bumping=20=
the sides) and how hot you want to go/ slow you want to cool.=C2=A0 I hit co=
ne 11 with out to much trouble at all. Hope this helps.=20

Bill=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0 Split-Fire Pottery (web-site being built)
-----Original Message-----
From: Larry Kruzan
To: CLAYART@LSV.CERAMICS.ORG
Sent: Wed, 15 Oct 2008 11:13 pm
Subject: Kiln Wall Thickness?

Hi All,
=20
My existing 100 c.f. kiln has 9=E2=80=9D IFB walls as did most other kilns=
I have
ired. Most (not all) of the commercial built small gas kilns seem to have
=C2=BD=E2=80=9D walls, some with fiber back-up, some without anything else.=
I have
cratched my head at this difference while looking at some of these kilns
nd wondered how well they held up after many
firings.
=20
Now I=E2=80=99m planning to build a new gas test kiln with a stacking space=20=
of 20
.f. or so. Three 12x24 shelves wide and 3 =C2=BD foot tall area. Given thi=
s
mall footprint I think that one row of bricks is structurally strong enough
ut I wonder about how it will handle the heat. Looking at Nils Lou=E2=80=
=99s book
The Art of Firing=E2=80=9D I see many kilns with single brick walls.
=20
So I would like to ask all our great kiln builders what would you do and
hy?
=20
Thanks,
Larry Kruzan
Lost Creek Pottery
www.lostcreekpottery.com
=20