Earl Brunner on tue 29 jul 03
Bisque is not much different than the actual soft brick that the
elements lay on/in. Not as porous, but similar, shouldn't be a problem.
-----Original Message-----
From: Clayart [mailto:CLAYART@LSV.CERAMICS.ORG] On Behalf Of Cat Yassin
Sent: Tuesday, July 29, 2003 11:18 AM
To: CLAYART@LSV.CERAMICS.ORG
Subject: Exploding bisque and Kiln Elements
Hi to all! In my last bisque I was firing a sculptural piece that
exploded in
my electric kiln. I suspect it wasn't quite as dry as I thought it
was... I
have removed all the pieces and vacuumed the kiln including vacuuming
the
spaces in the soft bricks that hold the elements. My question is, what
if I haven't
gotten all the shards out and there are some left and touching the
elements?
Cat Yassin on tue 29 jul 03
Hi to all! In my last bisque I was firing a sculptural piece that exploded in
my electric kiln. I suspect it wasn't quite as dry as I thought it was... I
have removed all the pieces and vacuumed the kiln including vacuuming the
spaces in the soft bricks that hold the elements. My question is, what if I haven't
gotten all the shards out and there are some left and touching the elements?
It was quite an explosion as there were big and little pieces everywhere and I
have seen some pieces on the elements that the vacuum just didn't suck up.
Fortunately this wasn't a glaze firing so the pieces are "dry". Will I have to
get every little piece off the elements? (And yes, it is unplugged from the
wall!)
Thanks in advance!
-Cat Yassin
Malcolm Schosha on tue 29 jul 03
Cat,
It was almost certainly chemically combined water that made the piece
explode. Chemically combined water remains no matter how long you let
the piece dry, and it does not burn out until you pass 800 F, or a
little higher. With pieces that have a lot of thickness, the
temprature rise must be VERY slow until you pass 800F. It is
probabily a good idea to make your sculpture as thin as is practicly
possible to reduce the chances of repeating the experience.
Malcolm
....................................................
--- In clayart@yahoogroups.com, Cat Yassin wrote:
> Hi to all! In my last bisque I was firing a sculptural piece that
exploded in
> my electric kiln. I suspect it wasn't quite as dry as I thought it
was... I
> have removed all the pieces and vacuumed the kiln including
vacuuming the
> spaces in the soft bricks that hold the elements. My question is,
what if I haven't
> gotten all the shards out and there are some left and touching the
elements?
> It was quite an explosion as there were big and little pieces
everywhere and I
> have seen some pieces on the elements that the vacuum just didn't
suck up.
> Fortunately this wasn't a glaze firing so the pieces are "dry".
Will I have to
> get every little piece off the elements? (And yes, it is unplugged
from the
> wall!)
> Thanks in advance!
> -Cat Yassin
>
>
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melpots@p...
william schran on wed 30 jul 03
Cat wrote about explosion of ware in kiln and asks: get every little piece off the elements?>
The simple answer is yes. Use a flashlight and a pair of needle nose
pliers in addition to the vacuum. The clay pieces will eventually get
overfired, flux and cause the element to burn out at that spot.
Bill
william schran on wed 30 jul 03
Earl wrote: elements lay on/in. Not as porous, but similar, shouldn't be a problem.>
I would think it might be a problem depending on the clay body. Some
clays containing iron or lower fire clays may begin to flux when
exposed to repeated heating in contact with an element and would lead
to a "burn out" at that spot, IMHO. I always vacuum out the element
grooves very carefully after any "accident" in any kiln.
Bill
claybair on wed 30 jul 03
I first vacuum the interior of the kiln then
gently pull out the coils and vacuum the grooves
in my L&L kiln first using a small brush attachment
then the long skinny vacuum tool.
Only did it once in 7 years & have had the same number
of glaze disasters & am hoping to never repeat the experience!
Gayle Bair
Bainbridge Island, WA
http://claybair.com
-----Original Message-----
From:william schran
Earl wrote: the
elements lay on/in. Not as porous, but similar, shouldn't be a problem.>
I would think it might be a problem depending on the clay body. Some
clays containing iron or lower fire clays may begin to flux when
exposed to repeated heating in contact with an element and would lead
to a "burn out" at that spot, IMHO. I always vacuum out the element
grooves very carefully after any "accident" in any kiln.
Hendrix, Taylor J. on wed 30 jul 03
Bill,
Sounds reasonable to clean out all the pieces, but if what
you say is true, why then do not the element channels eventually
flux and cause the elements to burn out?
Inquiring mind wants to know.
Taylor, in Waco
-----Original Message-----
From: william schran [mailto:wschran@EROLS.COM]=20
Sent: Wednesday, July 30, 2003 7:53 AM
To: CLAYART@LSV.CERAMICS.ORG
Subject: Re: Exploding bisque and Kiln Elements
Cat wrote about explosion of ware in kiln and asks: get every little piece off the elements?>
The simple answer is yes. Use a flashlight and a pair of needle nose
pliers in addition to the vacuum. The clay pieces will eventually get
overfired, flux and cause the element to burn out at that spot.
Bill
________________________________________________________________________
______
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.
Hendrix, Taylor J. on wed 30 jul 03
Oops! Brain Fart, ladies and gents.
Don't even try to answer that one, William.
I was envisioning my busted up, inoperative kiln
with all the kiln brick pieces everywhere, NOT=20
pieces of bisque as in the original post.
DUH! DUH! Double DUH!
Taylor, hanging his head in Shameco
-----Original Brain Fart-----
From: Hendrix, Taylor J.=20
Sent: Wednesday, July 30, 2003 4:10 PM
To: 'Clayart'
Subject: RE: Re: Exploding bisque and Kiln Elements
Bill,
Sounds reasonable to clean out all the pieces, but if what
you say is true, why then do not the element channels eventually
flux and cause the elements to burn out?
Inquiring mind wants to know.
Taylor, in Waco
william schran on thu 31 jul 03
Taylor wrote: you say is true, why then do not the element channels eventually
flux and cause the elements to burn out?>
I would suspect the IFB is much more refractory than any particular
clay being used. In my original message I suggested clays containing
iron or low fire clays may be of a particular problem. L&L kilns use
a high fire porcelain element holder, so perhaps high fire porcelains
or stonewares might not present a problem. Care to run a test? ;-)
Bill
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