Steve Dalton on fri 19 apr 02
Greetings,
I finally tried it...I've crossed the line...I've gone beyond black and
white. I finally bisqued in my gas kiln. It worked like a dream. Within 9
1/2 hours, I dropped ^07. Nothing blew up. I only loaded bone dry pots. I
lost count after 100 pots, I'm guessing 130-150 pots, enough for a load and
half of glaze. What a dream!!! Slick as snot!!! Thought I would share!!!
--
Steve Dalton
Clear Creek Pottery
Snohomish, Wa
sdpotter@gte.net
Eric Suchman on sat 20 apr 02
I never knew that gas bisqueing was a problem. It's the only kiln I ever
owned and it did every thing I needed it to do. Bisque one week glaze the
next. Never had a problem that wasn't my fault.
> From: Steve Dalton
> Reply-To: Ceramic Arts Discussion List
> Date: Fri, 19 Apr 2002 12:04:57 -0800
> To: CLAYART@LSV.CERAMICS.ORG
> Subject: Gas Bisque
>
> Greetings,
>
> I finally tried it...I've crossed the line...I've gone beyond black and
> white. I finally bisqued in my gas kiln. It worked like a dream. Within
9
> 1/2 hours, I dropped ^07. Nothing blew up. I only loaded bone dry pots.
I
> lost count after 100 pots, I'm guessing 130-150 pots, enough for a load
and
> half of glaze. What a dream!!! Slick as snot!!! Thought I would
share!!!
> --
> Steve Dalton
> Clear Creek Pottery
> Snohomish, Wa
> sdpotter@gte.net
>
>
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John Baymore on sun 21 apr 02
I finally tried it...I've crossed the line...I've gone beyond black and
white. I finally bisqued in my gas kiln. It worked like a dream. Withi=
n
9
1/2 hours, I dropped ^07. Nothing blew up. I only loaded bone dry pots.=
=
I
lost count after 100 pots, I'm guessing 130-150 pots, enough for a load a=
nd
half of glaze. What a dream!!! Slick as snot!!! Thought I would share!=
!!
Steve,
I guess you've just rediscovered the wheel !
I really don't know where or when the idea somehow crept into the handcra=
ft
ceramics field that bisquing is typically (or even solely) done in an
electric kiln. But it seems to have done so with a vengence in the last
15-20 years or so. Probably is the direct result of the advent of the
computerized controllers..... and the high "convenience factor" that
provides.
When I really started clay in the late 60's .......... if you had a large=
fuel kiln.....THAT was the tool of choice to bisque in. Wouldn't use the=
electric.... because it was too small, too inefficient, and the ware tend=
ed
to not get the air it needed...... resulting in firing defects in the
finish fire. Besides..... you could REALLY pack bisque stuff in a big ga=
s
kiln .
Bisquing in pretty much ANY kind of kiln is possible and not all that har=
d.
The main and SOLE advantage of an electric kiln that I can see is having=
access to a programmable controller to make it more of a "toaster" -like
operation. Which it does do....and does well.
BUT........ it is terribly energy inefficient IF you also have the
availibility of a large gas kiln. Electrics are usually woefully
underinsulated. The amount of exterior surface area (for heat loss) to t=
he
volume of ware fired is usually high. The ratio of the weight of the
refractories to the weight of the actual wares is usually poor. And the
centralized generation and distribution of electricity is pretty
inefficient (high CO2 output) when compared to burning an energy source
directly in the kiln.
Then there is the issue of having enough air flow through the bisque to
allow the oxidation of various materials in the clay body that has to
happen. In an electric without a local pickup (downdraft type) vent.....=
this can be problematic. Even with such a vent, a dense load can often
present problems.
Yes... you have to know HOW to fire a fuel kiln to bisque in it. But tha=
t
is sort of a given, in my mind. You also need to know how to operate an
electric kiln if you want to bisque in that. Knowing how to operate the
kiln is a seperate issue. And if you have a gas kiln that doesn't operat=
e
well....... poor primary aeration, poor BTU input control, etc. .........=
.
well that will cause you problems. But so will an electric kiln with "ba=
d"
controls. That's a kiln problem...... not something inherent about
bisquing.
So...... welcome "back" to a common practice..... that seems not to be so=
common anymore .
Best,
..............................john
"Who has been firing gas bisques for 32+ years."
John Baymore
River Bend Pottery
22 Riverbend Way
Wilton, NH 03086 USA
603-654-2752 (s)
800-900-1110 (s)
JohnBaymore.com
JBaymore@compuserve.com
"DATES SET: Earth, Water, and Fire Noborigama Woodfiring Workshop Augu=
st
16-25, 2002"
Ron Roy on sun 28 apr 02
There is something that can go very wrong with bodies that have more than a
little iron in them.
You must not reduce the iron as it can result in black coring - in other
words - over vitrified clay due to reduced iron oxide.
Best is to make sure there is lots of free oxygen - certainly no reduction
- and not too fast from 700C to the end.
You don't find out till you glaze fire - so if you get bloating - it may be
the bisque firing - and it can happen in electric kilns as well.
9 hours seems fast to me but much depends on how thick the clay is, how
much carbon is in the clay - and it can vary from batch to batch - and how
much iron is present. If the ware is stacked tightly and nested - you need
to be extra careful.
RR
>I never knew that gas bisqueing was a problem. It's the only kiln I ever
>owned and it did every thing I needed it to do. Bisque one week glaze the
>next. Never had a problem that wasn't my fault.
>
>> From: Steve Dalton
>> Reply-To: Ceramic Arts Discussion List
>> Date: Fri, 19 Apr 2002 12:04:57 -0800
>> To: CLAYART@LSV.CERAMICS.ORG
>> Subject: Gas Bisque
>>
>> Greetings,
>>
>> I finally tried it...I've crossed the line...I've gone beyond black and
>> white. I finally bisqued in my gas kiln. It worked like a dream.
Within 9
>> 1/2 hours, I dropped ^07. Nothing blew up. I only loaded bone dry pots.
I
>> lost count after 100 pots, I'm guessing 130-150 pots, enough for a load
and
>> half of glaze. What a dream!!! Slick as snot!!! Thought I would
share!!!
Ron Roy
RR #4
15084 Little Lake Road
Brighton
Ontario
Canada - K0K 1H0
Phone: 613-475-9544
Fax: 613-475-3513
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