June MacDonald on mon 10 dec 07
Hi Scott: Do it! In the year 2000, I transferred our art center from Cone 10 to Cone 6 reduction. The reasons I did it were fuel economy, and time.
The main hurdles I had to overcome were people who thought that there was something more magic about Cone 10 than Cone 6, not realizing that it is the reduction that matters most for results. Temokus, Copper reds, Shinos and Celadons are all possible and just as good looking in Cone 6 as they are in Cone 10, and someone who is not in the know about what temperature the pieces are fired at could not tell the difference.
Saving in time was enormous to me, about four hours for each firing. Saving in money I have to guess at because they they did not separate the meter for the kiln from the rest of the building. I have been told that it takes as much gas to get from Cone 6 to Cone 10 as it does from start to Cone 6. Four hours worth of gas pumping away has to be more expensive though.
Aesthetics - see above. The only thing I was not able to achieve was a satisfactory rutile blue, a tricky glaze anyway.
Clays- I tested numerous clay bodies. The iron rich or red Cone 6 bodies are not satisfactory. All Cone 6 porcelains that I have tested work well. Some of the honey coloured in electric firing clays turn a nice rich brown. We ended up using a clay called M340 from Plainsman in Canada, and Calico (nice rich brown) and B-Mix 5 from Laguna for the basic studio clays.
Glazes - surprisingly enough, some of the Cone 10 glazes worked well. Some need just a little tweaking to get a satisfactory result at Cone 6. Some of the previously electric Cone 6 glazes were successful, some melted a little too much in reduction. Test everything! At the same time as the temperature transfer I kicked gerstley borate out of the studio and reformulated all the glazes to eliminate this ingredient, usually replacing the boron needed with Frit 3134. Thank you GlazeMaster!
If you have any further questions, do not hesitate to contact me. I'm just a little north of you, just outside Vancouver, B. C.
June
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scott paulding on mon 10 dec 07
hello,
it has been a long time since i wrote the list.
i live in the seattle area. i work out of my basement, then bring my
raw pieces to a local arts center to get it bisque fired, glazed and
ultimately the work goes into the cone 10 redux kiln.
our director recently emailed a few of us, seeking out advice,
opinions, and ideas about dropping our firing temperature from cone 10
redux to cone 5 redux, and what this would mean for our students,
renters and studio artists.
her reasoning is that there would be at least a 30% savings in fuel
cost (propane, which is sky-rocketting in $$$), and a huge time
savings for the people who fire the kilns. she also says that since
they already do cone 5 ox firings in the electric kilns, maybe those
glazes would translate nicely to redux, and thus we would reduce the
numbers of glazes that we would have to carry. it's also a more
environmentally friendly to use less gas.
we are basically in the exploratory stages, and we are doing
feasibility studies, etc. what i am asking from this list's collective
intelligence are answers to these questions:
*have you ever experienced or attempted a shift like this?
*what hurdles did you have to overcome?
*was there really that big of a savings in time or money?
*what kinds of aesthetic differences are there between cone 5 and 10 redux?
*what kinds of differences are there in the clays?
*what about shinos/oribes/temmokus/copepr reds? are they reliable?
i throw primarily in porcelain, and i make a lot of teapots.
*what about a good cone 5-6 porcelain?
*how do all those teapot attachments hold up?
i've heard that since cone 5-6 porcelains have more feldspar, the
attachemnts are a lot more fussy. is this true?
is there anythign that i haven't thought to ask that you think is worthwhile?
thanks for all your input everyone.
-scott
Lynn Goodman Porcelain Pottery on mon 10 dec 07
>
> we are basically in the exploratory stages, and we are doing
> feasibility studies, etc. what i am asking from this list's collective
> intelligence are answers to these questions:
>
> *have you ever experienced or attempted a shift like this?
> *what hurdles did you have to overcome?
> *was there really that big of a savings in time or money?
> *what kinds of aesthetic differences are there between cone 5 and
> 10 redux?
> *what kinds of differences are there in the clays?
> *what about shinos/oribes/temmokus/copepr reds? are they reliable?
> i throw primarily in porcelain, and i make a lot of teapots.
> *what about a good cone 5-6 porcelain?
> *how do all those teapot attachments hold up?
> i've heard that since cone 5-6 porcelains have more feldspar, the
> attachemnts are a lot more fussy. is this true?
Hi Scott,
When I was in college in the 70's my ceramics program (at
Philadelphia College of Art, now University of the Arts) did exactly
what your director is planning to do. They tested any recipes they
could find for ^6 glazes in the gas kiln with excellent results. We
had typical reduction glazes at ^6; you could not tell that they were
not ^10. Yes, they saved a bunch of money. More to the point in
today's world: less gas=less reliance on unstable governments and a
greener world.
I suggest that you do what they did: solicit recipes from anyone who
will give them to you (I will send you a couple that I liked). Look
at the clayart archives as well. Look at recipes of oxidation glazes
to see if you can get them to do interesting things in reduction
(lots of them will easily make that transition).
As far as the clay, you may have noticed a lot of discussion on the
relative faults and benefits of various ^6 porcelains; you will need
to test all of what's available to you to find something you like (I
like Standard 551--I don't know if it's available in Seattle). Yes,
^6 porcelain has less clay in it; attaching handles is a pain in the
ass. You will have to be more careful about the dryness of the pieces
which will be receiving handles; wetter is better and always cover
your piece overnight after attaching anything to it.
Good luck!
Lynn
Lynn Goodman
Fine Porcelain Pottery
Cell 347-526-9805
www.lynngoodmanporcelain.com
Paul Gerhold on tue 11 dec 07
Dear Scott,
Think basically that you will be totally starting over armed only with the
general clay and glaze knowledge you currently posess.Your aesthetic goals will
have to change since glazes will be totally different. The concept that cone
10 reduction somehow translates to cone 6 neutral electric firing is just
plain ignorant!
I moved from cone 6 to cone 3 and it took almost two years to develop a
satisfactory glaze pallet. If you are a functional potter your pieces will become
less durable in all probability. You will have to develop more intricate or
involved glaze design work since in my opinion most lower firing glazes look
more like surface design and less like an integral part of the whole.
In general this type of radical shift can only be justified for the
following reasons.
1) you are unhappy with or bored with what you are doing now.
2) you are a glaze freak, love testing, and need a challenge in life.
3) You are a major production potter where energy cost rather than time is a
major factor in your success.
In summary I would say the change is probably good for those running the
kiln and bad for everyone else.
Paul
**************************************See AOL's top rated recipes
(http://food.aol.com/top-rated-recipes?NCID=aoltop00030000000004)
Jacqueline Miller on tue 11 dec 07
Scott: Go to www.glazeforward.com. Diana Pancioli has done extensive
research on C6 reduction glazes. You can ask to be sent test tiles to look
at for a small fee and all of her glaze formulations.Jackie
On Dec 10, 2007 2:41 PM, scott paulding wrote:
> hello,
>
> it has been a long time since i wrote the list.
>
> i live in the seattle area. i work out of my basement, then bring my
> raw pieces to a local arts center to get it bisque fired, glazed and
> ultimately the work goes into the cone 10 redux kiln.
>
> our director recently emailed a few of us, seeking out advice,
> opinions, and ideas about dropping our firing temperature from cone 10
> redux to cone 5 redux, and what this would mean for our students,
> renters and studio artists.
>
> her reasoning is that there would be at least a 30% savings in fuel
> cost (propane, which is sky-rocketting in $$$), and a huge time
> savings for the people who fire the kilns. she also says that since
> they already do cone 5 ox firings in the electric kilns, maybe those
> glazes would translate nicely to redux, and thus we would reduce the
> numbers of glazes that we would have to carry. it's also a more
> environmentally friendly to use less gas.
>
> we are basically in the exploratory stages, and we are doing
> feasibility studies, etc. what i am asking from this list's collective
> intelligence are answers to these questions:
>
> *have you ever experienced or attempted a shift like this?
> *what hurdles did you have to overcome?
> *was there really that big of a savings in time or money?
> *what kinds of aesthetic differences are there between cone 5 and 10
> redux?
> *what kinds of differences are there in the clays?
> *what about shinos/oribes/temmokus/copepr reds? are they reliable?
>
> i throw primarily in porcelain, and i make a lot of teapots.
> *what about a good cone 5-6 porcelain?
> *how do all those teapot attachments hold up?
>
> i've heard that since cone 5-6 porcelains have more feldspar, the
> attachemnts are a lot more fussy. is this true?
>
> is there anythign that i haven't thought to ask that you think is
> worthwhile?
>
> thanks for all your input everyone.
>
>
> -scott
>
>
> ______________________________________________________________________________
> Clayart members may send postings to: clayart@lsv.ceramics.org
>
> You may look at the archives for the list, post messages, or change your
> subscription settings here: http://www.acers.org/cic/clayart/
>
> Moderator of the list is Mel Jacobson who may be reached at
> melpots2@visi.com
>
--
Jackie Miller
JackieAMiller@gmail.com
Snail Scott on tue 11 dec 07
On Dec 10, 2007, at 11:00 PM, Automatic digest processor wrote:
>
> Date: Mon, 10 Dec 2007 11:41:23 -0800
> From: scott paulding
> Subject: going from cone 10 to cone 5
> *have you ever experienced or attempted a shift like this?
> *what hurdles did you have to overcome?
> *was there really that big of a savings in time or money?
> *what kinds of aesthetic differences are there between cone 5 and 10
> redux?
> *what kinds of differences are there in the clays?
> *what about shinos/oribes/temmokus/copepr reds? are they reliable?
I went from ^10 reduction to ^4 reduction while still in college,
and from there to ^6 oxidation some years later. I plan to
return to reduction as soon as I can afford to fill a 500 gal
propane tank.
I picked ^4 because I had a clay formula that worked well at
that temperature, and stuck with reduction because I liked the
effect on my red clay. ^6 hadn't yet become as standardized
it is now, though I eventually switched to it because my red
^4 body needed to go to ^6 in oxidation to get the same level
of vitrification. I've stayed there subsequently, through several
clay-body changes, because of the convenience of that
standardization.
Since I switched while I was still a student, I didn't perceive
the cost difference firsthand. I was looking ahead to the day
when I'd have to pay, though, and the cost difference seemed
quite significant, especially in underinsulated or hardbrick
kilns. Every cone of linear temperature increase was not
reflected by a linear cost increase, but a more geometric one,
as you try to pump heat into the kiln faster than it absorbs
and/or re-radiates it. I also noted that marginal or inefficient
kiln designs sometimes had real trouble even hitting ^10
reliably, especially at that altitude, while even an 'iffy' design
or old, battered kiln could almost always hit the mid-range
temperatures easily. So, by working at those temperatures,
I'd be less dependent upon having excellent equipment,
and I could 'make do' with second-string kilns if necessary.
As a young impoverished artist, keeping my options open
to more (and cheaper) possibilities seemed only sensible,
and as an older impoverished artist, it still does. Other
reasons reinforced that choice:
First, the lower temperatures seem less stressful to the clay,
and I seemed to get fewer cracks and less warping with a
similar level of vitrification. (This, however, may have been
due more to the change in clay than the change in temps.)
Second, the lower temperature expanded my range of color
choices to include stains that didn't survive to ^10. This
was the only distinct aesthetic change - the wider potential
color range. Nice shinos and copper reds are still possible,
too. A long soak at the top can really improve most glaze
results, giving an effect similar to the (usually) longer, slower
approach to peak temperatures typical of ^10 firings.
Third, I could utilize more commercial products. It's nice to
try new surface effects without investing the research time in
doing it all from scratch. There are many good reasons to
work from scratch, but also some good ones for utilizing
the expertise of the commercial glaze manufacturers,
especially for occasional or experimental needs. If I plan
to use something a lot, I'll make it from scratch, but that's a
pragmatic choice, not a moral virtue or an imperative.
Fourth, firings finished sooner, so I got more sleep on firing
nights. And, since the kiln started cooling sooner and from
a lower temperature, I could unload sooner the next day.
I could also re-load sooner if I wanted to, which gave me
much more schedule flexibility. Since I was the studio tech
at the time, loading and unloading was an everyday event,
and the ^10 firings were always being unloaded hot and
reloaded immediately, just to stay on schedule. Lower
temp loads were a real respite.
Fifth, as I suspected, I did eventually have to switch to
electrical firing for a while, and I still mainly work in
oxidation. ^10 is brutal on most electric kilns, and element
life is notably extended (and firings shortened - see above,
r.e. inadequate insulation) at lower temps. Switching to
oxidation was a lot easier when I could stay at the same
temperature (more or less), and most glazes work fine
(though sometimes differently). Even if you aren't currently
dealing with an impending switchover in atmosphere, it's
nice to be able to do so easily.
Many people do find midrange porcelain-type bodies to
be fussier, but some are better than others. How big an
issue this will be for you, I can't guess. Try several bodies.
Historically, ^10 was preferred because so many things
melt at that temperature, offering more choices in glaze
formulation. Nowadays, though, we have more materials
to choose from, including frits formulated for mid-range
temperatures. This, in my mind, does away with the
primary reason for ^10 firing in first place. Some processes
( e.g. atmospheric firings like wood or salt/soda) require
those higher temperatures because the choice of materials
(ash or sodium, etc) is a given. If that's not your passion,
however, I see no strong reason to stick with ^10.
-Snail Scott
John Britt on fri 14 dec 07
Scott,
I am going to say that it can be done, it has been done and that your
director is right, it will save money. A lot of money and time.
I just did a workshop at a fantastic place - Mudfire in Atlanta. They have
switched to cone 6 reduction and have very nice results. Erik or Luba are
doing a great job there trying to balance cost with results and the
changing needs of student populations. They have a gallery and a beautiful
drop in studio space and offer top notch workshops.
I am trying to write up an article on Mudfire and the workshop which went
well but to summarize it here; they have some nice copper reds, carbon
trap shinos, oribes, blues, eggshell, purple, white, etc. They can also
use these glazes in electric oxidation. So they have plenty of choices.
It is a good thing to try to reduce costs and fuel even if it takes work!
You don't have to be a genius to figure it out either.
Just my opinion,
John Britt
www.johnbrittpottery.com
William & Susan Schran User on fri 14 dec 07
On 12/14/07 9:59 AM, "John Britt" wrote:
> I am trying to write up an article on Mudfire and the workshop which went
> well but to summarize it here; they have some nice copper reds, carbon
> trap shinos, oribes, blues, eggshell, purple, white, etc. They can also
> use these glazes in electric oxidation.
Hey John, why not a follow up book to your High Fire book, a ^6
oxidation/reduction book.
--
William "Bill" Schran
wschran@cox.net
wschran@nvcc.edu
http://www.creativecreekartisans.com
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