mel jacobson on tue 19 dec 00
when you buy your own kiln, with your own money.
fire it with your electric bill.
then tell me cone 10 electric is just great.
mel
FROM MINNETONKA, MINNESOTA, USA
http://www.pclink.com/melpots (website)
Wesley C. Rolley on wed 20 dec 00
Mel wrote:
>when you buy your own kiln, with your own money.
>fire it with your electric bill.
>
>then tell me cone 10 electric is just great.
>mel
>
And to quote Mel from another posting:
>....find a good
>claybody and learn to use it. find a couple safe base recipes and
>learn to use them. once you have established some materials
>that you can trust and understand.....the pots then come from
>your brain...they become `your pots`.
I havn't spent 45 years learning one glaze. Hell, I have just begun this
journey, though it has been about 45 years since I bought my first pots at
the Coconino County Fair in Flagstaff, AZ. Two black on red vases that
won a ribbon and I gave them to my Mother for her birthday. When she
passed a few years ago, I got them back.
Now, I bought my kiln with my own money and I fire it with my
my own electric bill. Not only do I fire to a high temp, but I stick a lot
of stuff like unwashed fireplace ash into my glazes. (ITC goes on the next
set of elements.) To keep it simple, just some fireplace ash and redart
(well, sometimes I might add a little custer) because I happen to like
green drips on yellow pots or a blue/grey hare's fur over a warm tan. And
there is nothing that
feels so silky smooth to my hand that is not alive.
Now, I have backed down to cone 9, and will continue to test for lower
temps. But I still have a few years to study why there is so much
difference between 18 and 24% ash or why a pot looks better if I cool it
slowly. And how thick should the glaze be for which of the three colors
that are always available, or how to control where each color will be and
how far the drips will run.
Maybe one firing does save some energy. It is so easy to single fire with
this combo. Some pots have glaze that is thicker than the body and I have
not lost one yet to rim cracks. (not true with other glazes that I used).
And I only use one body, a warm toasty, groggy stoneware with lots of iron
to be sucked into the glaze.
God, I have so much to learn and so little time. So, which piece of your
advice should I follow?
Got a big jar to fire this week, too tall to even put it on a shelf with
six inch posts. A lot of juice for one pot. Then again, maybe I won't
risk it, since the utilities say they might be into "rolling blackouts"
tomorrow evening.
Wes
Wes Rolley
"Happiness is to be fully engaged in the activity that you believe in and,
if you are very good at it, well that's a bonus." -- Henry Moore
http://www.refpub.com
Maid O'Mud Pottery on wed 20 dec 00
Ooops, sorry to intrude...but I've been firing to ^10 in an electric kiln since
'88. Durable wear, great colours. I bought the kiln, I pay the bills. My
choice. This year I chose to have my elements coated with ITC (done by Tuckers for
me). The kiln is running hotter, faster and more predictably than ever, despite
the fact it's now almost 13 years old. We do all our own maintenance.
I'm planning on trying ^6 in January (my usual annual experimentation period) and
seeing what I get. If I don't like it, or if the ware isn't durable enough, I'll
stick with the ^10. Stayed tuned
mel jacobson wrote:
> when you buy your own kiln, with your own money.
> fire it with your electric bill.
>
> then tell me cone 10 electric is just great.
> mel
>
> FROM MINNETONKA, MINNESOTA, USA
> http://www.pclink.com/melpots (website)
>
> ______________________________________________________________________________
> 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.
--
Sam, Maid O'Mud Pottery
SW Ontario CANADA
http://www.geocities.com/paris/3110
scuttell@odyssey.on.ca
"First, the clay told me what to do
Then, I told the clay what to do
Now; we co-operate"
sam, 1994
"Effort does not always equal output"
sam, 1999
DEBBYGrant@AOL.COM on fri 22 dec 00
I guess it's time for me to jump into this thread. Some time ago my
electrical
engineer husband installed a meter at the site of my two electric kilns so
that
we could accurately guage what it is costing me to run them. I have a small
commercial kiln which I only use for bisquing and an 8 cubic foot home made
front loading kiln with 9 inch walls in which I do all of my glazing to ^10.
The
average cost of a bisque in the small kiln is $6.00 and in the large kiln
$16.00.
The average cost of a glaze firing to ^10 in the large kiln is $24.00. I
estimate
that a glaze firing to ^6 would only save me about $4.00 per firing. I have
been
working with clay for 40 years, starting out with earthenware at ^04,
switching
to ^06 using Bristol type glazes and finally ending with ^10 at least 25 years
ago. I was never satisfied with the look of the glazes at ^6 and would not
consider sacrificing the beauty of the ^10 glazes just to save $4.00 per
firing.
I also fire very slowly and seem to get an entirely different look with the
same
glazes that some of my friends get in their commercial kilns, probably due
to the fact that my kiln cools very slowly because of its thick walls.
Anyhow,
that's my take on ^10.
Debby Grant in NH
Janet Kaiser on fri 22 dec 00
Dear Debby and other electric kiln owners
Could you post the kilo-wattage you use
and not just what you pay in $, please? This
would make it possible for us all to work out
what
we would have to pay, if we were using your
kilns and firing the way you do...
Judging from other posts, there is a vast range
of charges for electricity within the US alone
and I am positive the rest of us have wildly
different rates too. Whether paying dollar, yen,
pound, krone or bhat, there are differences both
nationally and internationally.
It would be really useful if everyone using an
electric kiln could also state size & make of
kiln, length of time for various phases
(candling, firing, soaking, etc.) and
temperatures at each stage (not just final cone
#). I know the variables and combinations are
too numerous to correlate simply, but it would
help a lot of folk who are trying to decide what
kiln to buy.
Fridges, freezers, washing machines, etc. have
an A to E energy rating over here... "A" being
the most energy efficient and "E" being the
least. I wonder if it would be worthwhile asking
kiln manufacturers to employ such a system? Or
maybe they do already? Would it even be feasible
if they don't? Would that help folk decide on
electric vs. gas? Does anyone know of any
research in this area? Published results which
even I would understand?
I quite readily admit when talk is of wattage,
Btu, and all that thermal technical language my
brain tends to turn off! However, it would
appear to be a question we should all be taking
very seriously these days.
What ever or who ever is to "blame" for the rise
in the cost of energy, everyone should try to
reduce the amount used, for the simple reason it
is all fossil fuel and will not last for ever.
Now Mr. Bush is moving into the White House, I
guess drilling will start in Antarctica and
other regions we saved in the past, but even so,
the cost will still increase (prices never fall
for long), so we should all look at ways of
saving our own pockets, even if we are not
into saving the world.
Thanks
Janet Kaiser
The Chapel of Art . Capel Celfyddyd
HOME OF THE INTERNATIONAL POTTERS' PATH
Criccieth LL52 0EA, GB-Wales Tel: (01766) 523570
E-mail: postbox@the-coa.org.uk
WEBSITE: http://www.the-coa.org.uk
----- Original Message -----
> I guess it's time for me to jump into this
thread. Some time ago my
> electrical
> engineer husband installed a meter at the site
of my two electric kilns so
> that
> we could accurately gauge what it is costing
me to run them. I have a small
> commercial kiln which I only use for bisquing
and an 8 cubic foot home made
> front loading kiln with 9 inch walls in which
I do all of my glazing to ^10.
> The
> average cost of a bisque in the small kiln is
$6.00 and in the large kiln
> $16.00.
> The average cost of a glaze firing to ^10 in
the large kiln is $24.00. I
> estimate
> that a glaze firing to ^6 would only save me
about $4.00 per firing. I have
> been
> working with clay for 40 years, starting out
with earthenware at ^04,
> switching
> to ^06 using Bristol type glazes and finally
ending with ^10 at least 25 years
> ago. I was never satisfied with the look of
the glazes at ^6 and would not
> consider sacrificing the beauty of the ^10
glazes just to save $4.00 per
> firing.
> I also fire very slowly and seem to get an
entirely different look with the
> same
> glazes that some of my friends get in their
commercial kilns, probably due
> to the fact that my kiln cools very slowly
because of its thick walls.
> Anyhow,
> that's my take on ^10.
>
> Debby Grant in NH
Dennis Davis on sat 23 dec 00
DEBBYGrant@AOL.COM wrote:,
> My total firing time for a ^10 firing is 22 to 24 hours, starting out with all
> switches on low for 6 to 8 hours. The wattage varies according to the switching,
> but I can tell you that I average 18 kilowatt hours for a glaze kiln. That is an
> average of two thirds of a kilowatt in a 24 hour firing. At the time that we
> were monitoring the firings we were paying about 14cents per kilowatt hour which
> is rather high compared to other areas in the country.
Debby,
If you use 18 KWH per firing and you pay $0.14 per KWH, doesn't that come out to
$2.52 per firing? Perhaps that should be 180 KWH per firing. Then it would come
out to $25.20 per firing. That would reconcile with your previous message in which
you stated that the average glaze firing cost in the large kiln was $24.00.
My electric kilns are wired through a separate meter too. My very old 7 cubic foot
Paragon kiln ( Model A-99B) uses about 100 KWH for a Cone 10 glaze firing. I pay
about $0.08/KWH so glaze firings cost me about $8.00. Bisque firings in the same
kiln to cone 06 use about 50 KWH.
Merry Christmas to all on Clayart.
Dennis in Warrenton, VA
DEBBYGrant@AOL.COM on sat 23 dec 00
Dear Janet,
You have posed a rather difficult question regarding kilowattage since
my kiln is not a commercial one, but I will try to draw a picture for you.
The kiln has 29 elements which we wind ourselves. We use 14 gauge
Kanthal wire and several different resistances. The elements are attached
in series to 5 switches. Each switch has 2 settings, low and high, which
draw different currents. My total firing time for a ^10 firing is 22 to 24
hours, starting out with all switches on low for 6 to 8 hours. The wattage
varies according to the switching, but I can tell you that I average 18
kilowatt hours for a glaze kiln. That is an average of two thirds of a
kilowatt
in a 24 hour firing. At the time that we were monitoring the firings we
were paying about 14cents per kilowatt hour which is rather high compared to
other areas in the country. That was a year ago and our rate is probably
higher now. I hope this gives you an adequate picture. My husband is the
one who built the kiln and figures all these things out. In return I
sometimes
let him play with the clay.
Debby Grant in snow covered New Hampshire
Robert Santerre on sat 23 dec 00
Fantastic Debby, your data puts this entire discussion into a real life
perspective. For 4 bucks you can afford to make the esthetic choices that please
you as an artist - the expense is obviously trivial relative to all the other
material, equipment and especially labor costs that go into your work.
I applaud you and your favorite engineer for seeking knowledge and shedding the
light.
Bob
////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////
DEBBYGrant@AOL.COM wrote:
> I guess it's time for me to jump into this thread. Some time ago my
> electrical
> engineer husband installed a meter at the site of my two electric kilns so
> that
> we could accurately guage what it is costing me to run them. I have a small
> commercial kiln which I only use for bisquing and an 8 cubic foot home made
> front loading kiln with 9 inch walls in which I do all of my glazing to ^10.
> The
> average cost of a bisque in the small kiln is $6.00 and in the large kiln
> $16.00.
> The average cost of a glaze firing to ^10 in the large kiln is $24.00. I
> estimate
> that a glaze firing to ^6 would only save me about $4.00 per firing. I have
> been
> working with clay for 40 years, starting out with earthenware at ^04,
> switching
> to ^06 using Bristol type glazes and finally ending with ^10 at least 25 years
> ago. I was never satisfied with the look of the glazes at ^6 and would not
> consider sacrificing the beauty of the ^10 glazes just to save $4.00 per
> firing.
> I also fire very slowly and seem to get an entirely different look with the
> same
> glazes that some of my friends get in their commercial kilns, probably due
> to the fact that my kiln cools very slowly because of its thick walls.
> Anyhow,
> that's my take on ^10.
>
> Debby Grant in NH
>
> ______________________________________________________________________________
> 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.
Steve Mills on sat 23 dec 00
That is one of the nice things about firing slowly, your glazes have
time to settle themselves, rather like taking that extra moment to
ensure the coat you've just put on is comfy and you haven't pushed your
sleeves up your arms. Another one is that quite often your cone bends at
a lower indicated temperature than the one on the cone chart; the
benefit of accumulated heatwork. If you rush things, they tend to look
hurried. Ask any wood firer. My pots always look better for that extra
few hours.
Steve
Bath
UK
In message , DEBBYGrant@AOL.COM writes
>I guess it's time for me to jump into this thread. Some time ago my
>electrical
>engineer husband installed a meter at the site of my two electric kilns s=
>o
>that
>we could accurately guage what it is costing me to run them. I have a sm=
>all
>commercial kiln which I only use for bisquing and an 8 cubic foot home ma=
>de
>front loading kiln with 9 inch walls in which I do all of my glazing to ^=
>10.
>The
>average cost of a bisque in the small kiln is $6.00 and in the large kiln
>$16.00.
>The average cost of a glaze firing to ^10 in the large kiln is $24.00. I
>estimate
>that a glaze firing to ^6 would only save me about $4.00 per firing. I h=
>ave
>been
>working with clay for 40 years, starting out with earthenware at ^04,
>switching
>to ^06 using Bristol type glazes and finally ending with ^10 at least 25 =
>years
>ago. I was never satisfied with the look of the glazes at ^6 and would n=
>ot
>consider sacrificing the beauty of the ^10 glazes just to save $4.00 per
>firing.
>I also fire very slowly and seem to get an entirely different look with t=
>he
>same
>glazes that some of my friends get in their commercial kilns, probably du=
>e
>to the fact that my kiln cools very slowly because of its thick walls.
>Anyhow,
>that's my take on ^10.
>
>Debby Grant in NH
--
Steve Mills
Bath
UK
Craig Martell on tue 5 apr 05
Hi:
I fired cone 10 electric for several years. So did my wife. The kilns got
quite a workout or is it "worked over?"
One thing that helped a lot was I had a friend who was a kiln tech wind
heavier guage elements for me. All of the "center zone" elements were 14
guage Kanthal and the top and bottom elements were 13 guage. I don't know
what electric kiln manufacturers are doing now but in the past they would
sometimes use element wire as light as 16 guage, which burns out faster at
cone 8 and above. The heavier guage wire lasted much longer.
regards, Craig Martell Hopewell, Oregon
Arnold Howard on wed 6 apr 05
From: "Craig Martell"
> I fired cone 10 electric for several years. So did my wife. The kilns
> got
> quite a workout or is it "worked over?"
>
> One thing that helped a lot was I had a friend who was a kiln tech wind
> heavier guage elements for me. All of the "center zone" elements were 14
> guage Kanthal and the top and bottom elements were 13 guage. I don't know
> what electric kiln manufacturers are doing now but in the past they would
> sometimes use element wire as light as 16 guage, which burns out faster at
> cone 8 and above. The heavier guage wire lasted much longer.
I believe kiln manufacturers are moving toward heavier gauge elements. 12
gauge is commonplace now. But sometimes a design doesn't permit heavy gauge.
Sometimes a kiln is too small to accept all that extra element wire.
Sincerely,
Arnold Howard
Paragon Industries, L.P., Mesquite, Texas USA
arnoldhoward@att.net / www.paragonweb.com
Sam Hoffman on wed 6 apr 05
Hi Craig-
After pursuing the cone 11 tenmokus, oil spots, and kakis, I have been
very concerned about the impact such temps would have on my Skutt 1227.
I spoke with Kenny Simpson (a well know Oregon electric kiln builder)
about the new "super duty" elements that are sold by Skutt, which I
installed this winter. His take on them is that they are not worth the
additional money. They do have a slightly longer life, but in the
long run, it is cheaper to simply replace with the regular high fire
elements.
I have had good luck with coating the elements with ITC, but he also
seems to think this is more expensive than beneficial. It will be
interesting to see how these new refractories play out after they have
been in use for several decades.
Any other ideas for prolonging the life of a high-fire electric kiln?
Lovin' oxidation,
Sam
S.L. Hoffman Pottery
Corvallis, Oregon
www.samhoffman.com
On Apr 5, 2005, at 7:56 PM, Craig Martell wrote:
> Hi:
>
> I fired cone 10 electric for several years. So did my wife. The
> kilns got
> quite a workout or is it "worked over?"
>
> One thing that helped a lot was I had a friend who was a kiln tech wind
> heavier guage elements for me. All of the "center zone" elements were
> 14
> guage Kanthal and the top and bottom elements were 13 guage. I don't
> know
> what electric kiln manufacturers are doing now but in the past they
> would
> sometimes use element wire as light as 16 guage, which burns out
> faster at
> cone 8 and above. The heavier guage wire lasted much longer.
>
> regards, Craig Martell Hopewell, Oregon
>
> _______________________________________________________________________
> _______
> 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.
>
Larry Kruzan on sat 28 nov 09
Hi Nancy,
You are partially correct. Changing the atmosphere one fires in will result
in different colors, texture and "feel" of glazes. However, I detect that
you may see oxidation as inferior to reduction, to this I would differ.
One of my favorite con 10 copper red glazes is also a stunning turquoise in
oxidation. One glaze two colors, double your fun. Most reduction glazes liv=
e
these double lives, most often only showing the one. Be bold try a few in
oxidation for yourself.
Glazes are just combinations of minerals that can be fired to some effect.
The atmosphere they are fired in just determines if we like them. There
really are no reduction or oxidation glazes - there are just glazes. It can
be smoky reduction or crystal clear oxidation - you choose.
Take a look at my website and the pottery there. Here's a secret - about
half of what you see is in oxidation - about half of the glazes are
"reduction" glazes. If you say you can't tell which is which - that's the
idea. I love setting up a few pieces for my potter friends to pick out whic=
h
is which without turning them over to look at the clay.
Make up a bunch of test tiles, of several clay types and fire some samples
of all your "reduction" glazes in oxidation. As you try these tests be open
to new possibilities; layer the glazes, double dip them, try them on light
clay and dark. Some will be very boring, a few exciting but your vocabulary
of surface will be expanded with each tile. Take careful notes!
Pay special attention to the areas where one glaze meets with another. This
"interface" zone can often be the most exciting, areas that you can expand
by altering the thickness of the overlapping layer. Many think you must hav=
e
a reducing atmosphere to generate great microcrystalline structure - it jus=
t
isn't so my friend.
Have Fun,
Larry Kruzan
Lost Creek Pottery
www.lostcreekpottery.com
-----Original Message-----
From: Clayart [mailto:Clayart@LSV.CERAMICS.ORG] On Behalf Of N. Gallagher
Sent: Saturday, November 28, 2009 3:25 PM
To: Clayart@LSV.CERAMICS.ORG
Subject: Cone 10 electric
This question may be too 'basic' for clayart but here goes.
Why would people want to fire to cone 10 in an electric kiln? I'm
still learning, but aren't all electric kilns considered oxidation
kilns? Won't cone 10 glazes in oxidation look and perform very
similarly to cone 6 glazes in oxidation?
The only cone 10 recipes I've ever seen are reduction glazes and I'm
sure they'd look totally different fired in an oxidation atmosphere.
It seems like you're just using a lot more energy. Am I thinking
correctly - or, not??
Nancy
N. Gallagher on sat 28 nov 09
This question may be too 'basic' for clayart but here goes.
Why would people want to fire to cone 10 in an electric kiln? I'm
still learning, but aren't all electric kilns considered oxidation
kilns? Won't cone 10 glazes in oxidation look and perform very
similarly to cone 6 glazes in oxidation?
The only cone 10 recipes I've ever seen are reduction glazes and I'm
sure they'd look totally different fired in an oxidation atmosphere.
It seems like you're just using a lot more energy. Am I thinking
correctly - or, not??
Nancy
Paul Herman on sat 28 nov 09
Nancy,
Cone ten firing can include oxidation firing too, it's not just for
reduction. I've seen some very nice effects that came from my kilns
that were accidentally oxidized. Some high fired pots from Japan are
traditionally oxidized as are some from Europe. The colors produced
are very different from reduction firing, especially from iron. If a
potter works in oxidation and with sensitivity to the materials, great
work can be produced, of course.
So there are reasons to fire cone ten oxidation in electric kilns.
Best wishes,
Paul Herman
Great Basin Pottery
Doyle, California US
www.greatbasinpottery.com/
On Nov 28, 2009, at 1:24 PM, N. Gallagher wrote:
> This question may be too 'basic' for clayart but here goes.
>
> Why would people want to fire to cone 10 in an electric kiln? I'm
> still learning, but aren't all electric kilns considered oxidation
> kilns? Won't cone 10 glazes in oxidation look and perform very
> similarly to cone 6 glazes in oxidation?
>
> The only cone 10 recipes I've ever seen are reduction glazes and I'm
> sure they'd look totally different fired in an oxidation atmosphere.
> It seems like you're just using a lot more energy. Am I thinking
> correctly - or, not??
>
> Nancy
Marian Parkes on sat 28 nov 09
I can think of two reasons: Oilspot glazes and crystalline glazes.
I'm sure there are more.
Marian
Hank Murrow on sat 28 nov 09
On Nov 28, 2009, at 1:24 PM, N. Gallagher wrote:
> This question may be too 'basic' for clayart but here goes.
Nancy;
Your question is actually(as most beginning ones are) very good. I =3D20
wondered about that for many years while firing reduction in mostly =3D20
gas kilns. Then I began developing copper greens and blues and jet =3D20
blacks and eventually... copper yellow. All of these colors are =3D20
beautiful @ cone 10 Oxidation. So now every third firing is cone 10 =3D20
Ox. I find a depth of color and integration with the body optimum at =3D20
this temperature. I include a pic of several pieces... all fired at =3D20
cone 10 Ox.
=3DEF=3DBF=3DBC
>
> Why would people want to fire to cone 10 in an electric kiln? I'm
> still learning, but aren't all electric kilns considered oxidation
> kilns? Won't cone 10 glazes in oxidation look and perform very
> similarly to cone 6 glazes in oxidation?
Actually, my oxidation glazes would not turn out well in most =3D20
electrics because they fire in a neutral atmosphere, while my gas =3D20
kiln can readily fire in complete oxidation if desired.
>
> The only cone 10 recipes I've ever seen are reduction glazes and I'm
> sure they'd look totally different fired in an oxidation atmosphere.
> It seems like you're just using a lot more energy. Am I thinking
> correctly - or, not??
It does require more energy to fire to cone 10, no matter the =3D20
atmosphere, and the wear and tear on kiln and furniture is =3D20
significantly greater than @ cone 5. However, since I built a =3D20
wonderful kiln that will fire in any mode known to me and up to cone =3D20
13........ I love having the choice. And since my kiln only costs =3D20
around $30 for a longish(28 hours plus a 6 hour soak during the =3D20
cooling) cone 10+ firing...... one small bowl pays for 28 cuft of =3D20
ware. A great deal any way you slice it.
See the kiln @ http://www.murrow.biz/hank/kiln-and-tools.htm
Cheers, Hank in Eugene
Fuzzy Chef on sat 28 nov 09
N.,
> Why would people want to fire to cone 10 in an electric kiln? I'm
> still learning, but aren't all electric kilns considered oxidation
> kilns? Won't cone 10 glazes in oxidation look and perform very
> similarly to cone 6 glazes in oxidation?
Actually, the glazes are not the same. I have several Cone 9 oxidation
glazes which have proven impossible to lower to Cone 6, particularly a
bronze glaze and a wood ash glaze. Also, white stoneware fired to cone
9 or 10 is slightly more durable than Cone 6 ware in my experience.
However, I've stopped firing to Cone 9 after the last time I rebuilt my
kiln to repair bricks and add new coils.
--Fuzzy Chef
Lee Love on sat 28 nov 09
Nancy,
Several folks fire cone 9/10 electric at Northern Clay Center.
I have an Alfredd Chun an NCC friend gave me. He put a little
copper in it for a fake celadon in electric.
I always wonder why folks fire at cone 6. I fire at cone 03 and
have a very serviceable clay body.
--
Lee, a Mashiko potter in Minneapolis
http://mashikopots.blogspot.com/
"Ta tIr na n-=3DF3g ar chul an tI=3D97tIr dlainn trina ch=3DE9ile"=3D97tha=
t is, "T=3D
he
land of eternal youth is behind the house, a beautiful land fluent
within itself." -- John O'Donohue
Snail Scott on sun 29 nov 09
On Nov 28, 2009, at 3:24 PM, N. Gallagher wrote:
> Why would people want to fire to cone 10 in an electric kiln? I'm
> still learning, but aren't all electric kilns considered oxidation
> kilns? Won't cone 10 glazes in oxidation look and perform very
> similarly to cone 6 glazes in oxidation?
So, this is really two questions:
"Why ^10?" and 'Why electric?"
The biggest reason people fire to the higher
temperatures is that more things melt at higher
temperatures. It's not the only reason, but it's
definitely among the most significant.
At higher temperatures, you can choose from
a far wider range of minerals for your glazes,
and many more clay formulations. You have a
flexibility that is lacking in mid-range firing.
Historically, this was especially important since
you couldn't just add in exotic ingredients from
some far-flung locality; you had to work with
what was available naturally and locally.
Importing colorant oxides from far away was one
thing; shipping bulk clays and feldspars would
have been crazy and costly.
So, there has tended to be a big split in firing
ranges: either earthenware (^010-04 or so) for
the sake of bright colors, local low-fire clay
deposits, and/or easy-to-achieve temperatures,
or high stoneware (^8-12 or so) for vitrification,
and a wider range of melters for glazes. For a
long time, what we now call 'mid-range' was a
sort of no-man's-land: too hot for low-tech kilns
and bright low-fire colors, and too low for most
feldspars and other minerals to be useful melters.
It was severely limited in terms of chemistry on
one hand and color on the other.
It was the advent of new frits and colorant stains
that really made mid-range firing the common
practice it has become lately. The basic reasons
for preferring ^10 have thus been diminished, but
not eliminated.
Many interesting glazes cannot be reformulated
for mid-range, since their particular qualities are
formed by their chemistry, and those minerals
just need more heat to melt. Some clays, too, have
no real lower-temperature equivalent; porcelain is
one example. For some practitioners, 'pretty close'
just doesn't give them what they want from their
work.
> The only cone 10 recipes I've ever seen are reduction glazes and I'm
> sure they'd look totally different fired in an oxidation atmosphere...
Some yes, some no. One reason that people doing
high-fire have tended to prefer reduction is for the
sake of the 'reduction look', which differentiates
it from both earthenware and factory-made products:
the deeper tone of the clay, the altered range of
glaze colors, etc. Also, reduction can have a strong
effect on vitrification. High-fire in oxidation still confers
the benefits mentioned previously, though, especially
the wide range of potential materials and formulations.
The "This is not a factory product" reduction aesthetic
has dominated high-temp studio ceramics for decades,
but it was not always the case, and in any case oxidation
never vanished; it was just less fashionable for a while.
However, most people doing ^10 (whether reduction
or oxidation) have generally used fuel kilns built with
lots of heating capacity and lots of insulation. Electric
kilns (outside of industry) have tended to be built to
hobbyist standards, and are hard-pressed to reach
^10 effectively. This the other big reason for the move
to ^6: Once oxidation became more accepted again
among serious clayworkers, more people saw electric
kilns as a viable tool, but more so if they could work at
lower temperatures, saving element life and shortening
firings.
So, midrange firing has benefitted from the resurgence
in respectability for oxidation, and been supported by
the newly improved ranges of frits and stains, and the
wider interest in saving energy has also promoted it.
But it will never be identical to ^10.
So why does someone work at ^10 in electric, instead of
fuel-firing in oxidation? For some of the same reasons
that someone might fire electrically at any temperature:
It is easy, requiring minimal tending and freeing the artist
to do other things in the studio or elsewhere. It can be
plugged in anywhere, making more properties into
potential studio spaces. Electric is easier to insure than
a home-built fuel-belching monster, and cheaper than
a commercial fuel kiln. They are also easier to transport,
if moving seems likely in the future. Electric kilns are
also predictable, giving near-identical results firing after
firing, and not likely to slide into reduction every time a
low-pressure storm front moves through. And electric
kilns can be computerized - a real asset if you are firing
crystalline glazes. Sure, you have to replace the elements
pretty often, but that's just the cost of doing the work, like
using grolleg, or inclusion stains, or overglaze lusters, or
any number of other costly choices that we make because
they make our work better (in our own estimation as its
maker) than it would be using cheaper, more 'sensible'
options.
-Snail
Lmiller on mon 30 nov 09
I like this thread. My experience with 3 gas kilns (but only a few attempts=
=3D
) is that c10 electric=3D20
oxidation is different (cleaner?) than anything I can get from the gas kiln=
=3D
. I think I achieve=3D20
neutral and spotty oxidation in the gas kiln, but a few glazes I have used =
=3D
at c10E are way better=3D20
in the electric. I'm still firing to c8 and c10 in my old crusader 220s by=
=3D
the way. only costs=3D20
about $5 a pop! spare elements are still waiting in a drawer nearby.
Larry Miller in nw michigan
Paul Haigh on mon 30 nov 09
Nancy- if I had access, I'd do oil spot glazes. Oooh- good stuff
-pH
http://wileyhill.com
>From: Clayart [mailto:Clayart@LSV.CERAMICS.ORG] On Behalf Of N. Gallagher
>Sent: Saturday, November 28, 2009 3:25 PM
>To: Clayart@LSV.CERAMICS.ORG
>Subject: Cone 10 electric
>This question may be too 'basic' for clayart but here goes.
>Why would people want to fire to cone 10 in an electric kiln? I'm
>still learning, but aren't all electric kilns considered oxidation
>kilns? Won't cone 10 glazes in oxidation look and perform very
>similarly to cone 6 glazes in oxidation?
Dean on tue 15 dec 09
aloha all. I was just going over my old unread clayArt posts and thought I'=
=3D
d comment on this. I've been firing cone 10 oxidation for 25 years in elect=
=3D
ric, gas, and wood kilns.=3DA0 I've posted some of my recipes on ClayArt if=
y=3D
ou search for my old posts.=3DA0=3D20
Another reason besides the ones mentioned for cone 10 oxidation is consiste=
=3D
ncy.=3DA0 I have to make a living and having a consistently high percentage=
o=3D
f 'firsts' in my firings helps to keep the cash flowing.=3DA0 Oxidation is =
a =3D
very consistent way to fire.=3DA0 I've been able to duplicate or approximat=
e =3D
many reduction glazes in oxidation like celedon, tenmoku, copper red, flamb=
=3D
e,=3DA0 and rutile blue.=3D20
A common misconception about firing this hot in an electric is that it is h=
=3D
ard on the elements and replacement is frequent. Most electric kilns, even =
=3D
with 3" brick, are woefully underinsulated.=3DA0 Getting up to cone 10 is v=
er=3D
y stressful for the elements. Imagine running your car at top speed every t=
=3D
ime you drove it. It wouldn't last too long. I added a 1" layer of ceramic =
=3D
fiber to my last electric kiln and it fired MUCH easier and faster, saved l=
=3D
ots of money, and gave me 200+ glaze firings on a set of elements ( I lost =
=3D
count.)
I fire in a gas updraft now.=3DA0 Another reason for me is that it's cheape=
r =3D
than reduction.=3DA0 Propane is $4.50/gal. in Hawaii now and not getting ch=
ea=3D
per.
I like reduction, too.=3DA0 It's all good.
Dean
lightwavepottery.com
(all the high-fire work on my website is cone 10 oxidation)
=3D0A=3D0A=3D0A
Lee Love on wed 16 dec 09
On Tue, Dec 15, 2009 at 11:30 PM, Dean wrote:
> I fire in a gas updraft now.=3DA0 Another reason for me is that it's chea=
pe=3D
r than
> reduction.=3DA0 Propane is $4.50/gal. in Hawaii now and not getting cheap=
er=3D
.
> I like reduction, too.=3DA0 It's all good.
Dean,
Is it difficult to get wood for fuel in Hawaii? Because of
propane cost, more potters in Japan are looking at firing waste wood.
--=3D20
--
Lee, a Mashiko potter in Minneapolis
http://mashikopots.blogspot.com/
"Ta tIr na n-=3DF3g ar chul an tI=3D97tIr dlainn trina ch=3DE9ile"=3D97tha=
t is, "T=3D
he
land of eternal youth is behind the house, a beautiful land fluent
within itself." -- John O'Donohue
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