Wade Blocker on wed 19 may 99
Two reasons I switched entirely to an electric kiln : age and convenience.
My age that is. I have been working with clay for over thirty years. My
gas kiln was installed outdoors which meant having to carry kiln furniture
and ware to it. During the cold Winter months I could not use it (it cooled
off too quickly after a firing) and in Summer I felt I was baking along
with my pots. The one inch kiln shelves just became too heavy to lift. My
electric kiln is in my workshop. Firing it is a no brainer compared to my
temperamental gas kiln. Hope this explains my choice of firing. I opened
my kiln today. A glaze firing that was an unmitigated disaster. Little
white spots on everything but one bowl. Have to see what went wrong
tomorrow, when I`ll feel more resigned to the situation. I am not a
production potter, make one of a kind items, which allows me to play with
different glazes. Mia in Albuquerque, where Summer seems to have begun in
earnest.
Elizabeth Herod on wed 13 nov 02
Hi everyone--
I=B9d like to hear what people have to say on the advantages of gas vs.
electric kilns.
My impression was that gas is more versatile, but, at the same time, more
variable and harder to control.
Also, I=B9d like to know if anyone has tried a combination of copper sulfate
and borax in pit firing and what results were achieved. Can you really get
red? =20
I once got a red, but that was taking a small porcelain pot that had been
through one pit firing, putting it in a used coffee filter with a stretched
out copper scruffy thing, adding baking soda, baking powder and wetting the
soda and powder with liquid violet fertilizer. (ah, the pot blew up in the
fireplace, but the shards are red)
Beth
(the mad chemist)
Snail Scott on thu 14 nov 02
At 05:39 PM 11/14/02 -0800, you wrote:
>The fact is that its hard to argue [looking at my results] that one
>gets a better oxidizing firing in a gas kiln with the vents open than in an
>electric.
Pretty natural, when you think about it. We bisque
clay with the hope of BURNING OFF the organics.
I've noticed distinct reduction effects from clays
with organic matter even when fired electrically.
That 'micro-combustion' going on inside your clay
is not a trivial effect. I wouldn't be surprised to
learn that electric kilns actually produce a slight
reducing atmosphere during a bisque firing.
-Snail
Lily Krakowski on thu 14 nov 02
VS comes from the lawyers and means opposed to, or against, or something
equally hostile. So let me scratch that right now. It is gas OR electric.
Both give superb results if handled right, and "you gotta be kidding"
results if not.
Reduction firing has become the sine qua non (realistic translation:
obsession) of American potters. Long history, makes no never mind.
But much equally traditional American potters worked with muffle kilns and
electric from the get go of their careers. So you ain't alone out there.
In Great Britain there were Lucie Rie, Hans Coper, and are Eileen
Lewenstein, Emmanuel Cooper etc. who work MAGNIFICENTLY with electric
kilns.
The often heard argument that you cannot achieve GLORIOUS results with
electric kilns is bogus. You certainly can.
Cardew points out that electricity is a harsher judge of pots than
reduction. I point out that fuel burners give a pot the mercy candle light
does a face. Electricity is a harsh judge. If one has complexion problems
(i.e. glaze problems ) candlelight is kinder than 250v floods.
Having said that. A lot depends on your circumstances. Gas kilns take up
more room, require more precautions, you need to be sure you can get enough
gas--apparently in some areas the utility will not deliver tanks or meters
big enough for kilns--I think this has to do with zoning. Gas kilns weigh
more as a rule and so you need to know your floor can do it.
Gas kilns require full time supervision. Electric kilns can be left alone
for times. One can teach another person, a non potter, to turn the switches
up at given times. I would not trust a non-potter to watch my gas kiln. I
do candle my electric kiln at night, while I am in the house not the studio.
It is my impression that electric kilns are cheaper from the get go.
Meaning that a beginner can buy an adequately sized electric kiln for a
relatively modest amount, but not a gas kiln. I may be wrong there.
While no kiln is easy to move, my guess is an electric kiln is realtively
easier to move than a gas one. Think of that if you are not nailed to where
you now live/work.
I expect this will bring much "how wrong can you get" response. NB: I will
be off Clayart till Monday. The NOMAIL goes in as soon as I finish all
this.
was that gas is more versatile, but, at the same time, more
> variable and harder to control.
>
> Also, Iąd like to know if anyone has tried a combination of copper sulfate
> and borax in pit firing and what results were achieved. Can you really get
> red?
>
> I once got a red, but that was taking a small porcelain pot that had been
> through one pit firing, putting it in a used coffee filter with a stretched
> out copper scruffy thing, adding baking soda, baking powder and wetting the
> soda and powder with liquid violet fertilizer. (ah, the pot blew up in the
> fireplace, but the shards are red)
>
> Beth
> (the mad chemist)
>
> ______________________________________________________________________________
> 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.
Lili Krakowski
P.O. Box #1
Constableville, N.Y.
(315) 942-5916/ 397-2389
Be of good courage....
Rob Haugen on thu 14 nov 02
The choice between gas or electric can be as simple as asking yourself if
you want to do reduction firing. If you do want to fire in reduction, then
gas is your answer. If you only want to do oxidation firing, then electric
is a much better choice. Gas is a more difficult way to fire, but the
results can be fantastic.
Rob Haugen
Olympic Kilns
----- Original Message -----
From: "Elizabeth Herod"
To:
Sent: Wednesday, November 13, 2002 11:24 PM
Subject: Gas vs electric
Hi everyone--
Iąd like to hear what people have to say on the advantages of gas vs.
electric kilns.
My impression was that gas is more versatile, but, at the same time, more
variable and harder to control.
Also, Iąd like to know if anyone has tried a combination of copper sulfate
and borax in pit firing and what results were achieved. Can you really get
red?
I once got a red, but that was taking a small porcelain pot that had been
through one pit firing, putting it in a used coffee filter with a stretched
out copper scruffy thing, adding baking soda, baking powder and wetting the
soda and powder with liquid violet fertilizer. (ah, the pot blew up in the
fireplace, but the shards are red)
Beth
(the mad chemist)
____________________________________________________________________________
__
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.
Hank Murrow on thu 14 nov 02
On Thursday, November 14, 2002, at 05:32 AM, Rob Haugen wrote:
> The choice between gas or electric can be as simple as asking yourself
> if
> you want to do reduction firing. If you do want to fire in reduction,
> then
> gas is your answer. If you only want to do oxidation firing, then
> electric
> is a much better choice. Gas is a more difficult way to fire, but the
> results can be fantastic.
>
> Rob Haugen
> Olympic Kilns
>
Dear Bob;
I would add that electrics fire mostly in Neutral conditions. If you
want Oxidation, you need to move some air through your electric
kiln...............
or fire with fuel.
Best, Hank in Eugene
Snail Scott on thu 14 nov 02
At 07:21 AM 11/14/02 -0800, Hank wrote:
>I would add that electrics fire mostly in Neutral conditions. If you
>want Oxidation, you need to move some air through your electric
>kiln...or fire with fuel.
This is a good point. When we say 'oxidation' to
mean 'not-reduction', we are usually referring to
a neutral atmosphere, seldom to an actual oxidizing
atmosphere. I take this as a conventional common
usage, and use the term myself in this manner. It
is still not technically correct, in spite of
'conventional usage'. I figure there's no chance
of changing the convention, so I don't fight it,
but it is worth having these occasional reminders
about what we actually mean when we say it!
-Snail
Jose A. Velez on thu 14 nov 02
Hank wrote:
> I would add that electrics fire mostly in Neutral conditions. If you
> want Oxidation, you need to move some air through your electric
> kiln...............
Hank, could you further explain this. I thought technically oxidation meant
there is enough free Oxygen in the chamber to oxidized components in the
ceramic materials to the fullest potential, and in reduction by contrast
active CO in the flue gas combines with Oxygen depriving the ceramic
material, so the oxidation process is not completed. What is the neutral
state? How does it affect the glaze, colors, etc.? Any insight on this
will help. Thanks.
Jose A. Velez
Elizabeth Herod on thu 14 nov 02
Thank you to everyone who replied to my post regarding gas and electric
kilns. I very much enjoy what everyone has to say. I did particularly
enjoy the posts about fuel and firing. (oh dear, I think that you might
have given me some ideas about other ways to use my smoker, other than for
food)
My intent was to hear the reasons why members of the list prefer one over
the other. I realize that the most important issue is what suits one=B9s
needs. =20
I enjoy experimenting. I like to use a combination of two glazes over and
over to see the varied results. When I feel that I understand the
characteristics of the glaze, I try another two or three glazes. I do not
look for exact duplicates, since I want each piece of mine to be slightly
different from another member of its =B3family=B2. I like to create =B3families.=
=B2
I usually do this with thrown and altered pots or strictly handbuilt pieces=
.
I use porcelain, stoneware and raku clay. It depends on the day as to what
clay I am going to use.
I also make my own colored clay, and sometimes use it in my handbuilt
pieces. There are, of course, always exceptions, and if a friend or family
member wants something in particular, I will try and create what it is that
they want. A number of vessels that I make are for the purpose of Ikebana,
so that is another driving force.
I make similar pieces, raku some of them and sawdust fire the others. I am
interested in many processes and try to learn as much as I can about them.
Then I make a decision as to whether or not I want to use a particular
process. For example, I went to a Jeff Shapiro workshop, used his clay, ha=
d
it fired in his anagama kiln, was happy with the results, but it is not wha=
t
I want to do at the moment.
So, in my opinion, a gas kiln, though harder to use would better suit my
needs. I also have a number of friends with electric kilns, and the school=
,
so we=B9ll trade off if I need it. OTOH, I think it would be a really good
thing to learn how to use the gas kiln for everything. I=B9m not looking for
something that I set the controls and it does it for me. Someday, I might
be there, but not today. As someone previously likened electronics in the
kitchen to not really cooking, one could conceivably say the same thing
about a kiln that runs itself.
Throughout the years, depending upon my living circumstances, (apt in Sao
Paulo, tiny apt in NYC), I have had to adapt my art according to space,
cost, etc. The last several years have been the first since college that I
can use whatever medium I choose, and spend some money on the things that I
need or perceive that I need.
Beth
P. S. I really think it was unnecessary to correct my usage of vs in my
post, but since the door has been opened..... Lawyers do not use vs, they
use v. VS is often used when comparing features of different items.
Tom's E-mail on thu 14 nov 02
Jose, you wrote "I thought technically oxidation meant
there is enough free Oxygen in the chamber to oxidized components in the
ceramic materials to the fullest potential, and in reduction by contrast
active CO in the flue gas combines with Oxygen depriving the ceramic
material, so the oxidation process is not completed. What is the neutral
state? How does it affect the glaze, colors, etc.? Any insight on this
will help. Thanks"
I experienced an interesting effect several months ago and I believe Hank
gave me the best explanation. I have an electric and gas kiln. I usually
bisque fire in my electric and I get a nice light tan color. Some months ago
I had a lot of pieces I wanted to bisque and since my gas kiln is larger
than my electric, I fired in gas with the flue/vents wide open wanting good
oxidation. When I opened my kiln all my ware was white. I had thought I
would get some reduction and was really puzzeled why my ware turned out
lighter in gas/oxidation than electric/oxidation. Hank made almost the same
comment to me as his response to you. The free flow of oxygen was greater in
my gas kiln due to the open vents than in my closed system electric hence
the lighter color. I had several other people respond to my question why my
bisque ware was lighter in my gas kiln and Hank's was the most reasonable
answer. The fact is that its hard to argue [looking at my results] that one
gets a better oxidizing firing in a gas kiln with the vents open than in an
electric.
Tom Sawyer
tsawyer@cfl.rr.com
Roger Korn on fri 15 nov 02
When bisque firing light buff clays in an electric kiln before and after
installation of an Orton positive flow kiln vent on a Skutt electric, I
noticed that the vented bisques were lighter in color than the unvented
bisques. Same production run of ware, same cone, same everything except
for the vent.
Has anyone noticed small changes in color of atmosphere-sensitive glazes
in vented vs. unvented electric kilns? This might give a clue. Also,
what does an Oxyprobe read in vented/unvented electric kilns? Hank,
could you try this during a firing, turning the vent off and on and
seeing if the Oxyprobe reading shifts?
Just curious,
Roger
Tom's E-mail wrote:
>Jose, you wrote "I thought technically oxidation meant
>there is enough free Oxygen in the chamber to oxidized components in the
>ceramic materials to the fullest potential, and in reduction by contrast
>active CO in the flue gas combines with Oxygen depriving the ceramic
>material, so the oxidation process is not completed. What is the neutral
>state? How does it affect the glaze, colors, etc.? Any insight on this
>will help. Thanks"
>
>I experienced an interesting effect several months ago and I believe Hank
>gave me the best explanation. I have an electric and gas kiln. I usually
>bisque fire in my electric and I get a nice light tan color. Some months ago
>I had a lot of pieces I wanted to bisque and since my gas kiln is larger
>than my electric, I fired in gas with the flue/vents wide open wanting good
>oxidation. When I opened my kiln all my ware was white. I had thought I
>would get some reduction and was really puzzeled why my ware turned out
>lighter in gas/oxidation than electric/oxidation. Hank made almost the same
>comment to me as his response to you. The free flow of oxygen was greater in
>my gas kiln due to the open vents than in my closed system electric hence
>the lighter color. I had several other people respond to my question why my
>bisque ware was lighter in my gas kiln and Hank's was the most reasonable
>answer. The fact is that its hard to argue [looking at my results] that one
>gets a better oxidizing firing in a gas kiln with the vents open than in an
>electric.
>Tom Sawyer
>tsawyer@cfl.rr.com
>
>______________________________________________________________________________
>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.
>
--
Roger Korn
McKay Creek Ceramics
In AZ: PO Box 463
4215 Culpepper Ranch Rd
Rimrock, AZ 86335
928-567-5699 <-
In OR: PO Box 436
31330 NW Pacific Ave.
North Plains, OR 97133
503-647-5464
Tom's E-mail on fri 15 nov 02
Beth,
If I were to buy a single kiln today, I would purchase an electric that
could also fire gas or make sure I could easily modify it in the future so
it would do both. Spraying the elements with ITC up front would allow the
kiln to be modified in the future without having to replace the elements and
would provide for more efficient electric firing initially. If a kiln had a
small plug at its bottom which would allow the insertion of a small gas jet
at some future time and a small top plug, it would be all set for later use
as electric or gas. Howard Axner modified an electric in such a manner and
has been using it for nearly a year with good results. He uses a small
burner and small amounts of gas to get reduction. The advantage of such a
kiln is that your not locked in to just electric if you later change your
mind; another advantage is that its easier to bisque fire in an electric
even if your glaze firings are with gas.
Tom Sawyer
tsawyer@cfl.rr.com
hmurrow@EFN.ORG on sun 17 nov 02
Quoting Roger Korn :
> When bisque firing light buff clays in an electric kiln before and after
> installation of an Orton positive flow kiln vent on a Skutt electric, I
> noticed that the vented bisques were lighter in color than the unvented
> bisques. Same production run of ware, same cone, same everything except
> for the vent.
>
> Has anyone noticed small changes in color of atmosphere-sensitive glazes
> in vented vs. unvented electric kilns? This might give a clue. Also,
> what does an Oxyprobe read in vented/unvented electric kilns? Hank,
> could you try this during a firing, turning the vent off and on and
> seeing if the Oxyprobe reading shifts?
>
> Just curious,
>
> Roger
Dear Roger;
I would LOVE to try your suggestion, but alas, my OxyProbe is built in more or
less permanently to my lifting kiln. Besides, the electric I use for bisque
doesn't have a vent system. Maybe someone else on the List will be able to
accommodate us and our question.
Cheers from Ashland, OR...where the folks in Clayfolk are grand and attentive.
------------------------------------------------------------
Visit http://www.efn.org for all your community networking needs
Mary-Helen Horne on sat 23 nov 02
On Thu, 14 Nov 2002 17:39:37 -0800, Tom's E-mail wrote:
The free flow of oxygen was greater in
>my gas kiln due to the open vents than in my closed system electric hence
>the lighter color.
So, based on this, would one get the same oxidation effects in an electric
if peepholes are left open and the lid cracked? (Of course, you'd need
more electricity, and I presume it might be harder on the elements.)
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