John Baymore on wed 21 oct 98
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(snip)
Many potters I know would love to try this, as they do not have
accesss to gas fired kilns nor the resourses for it. I myself
would love more information on the subject.
............. (some of us cannot do that in the area
we live in=21) ...............................(then why are some not doing
it?).
...........Anyone know where I could get more info on this subject?
(clip)
Julie,
While there are certainly a lot of =22craft potters=22 (folks that form the
clay as well as glaze it) that use electric kilns, there is a really huge
market in the =22hobby ceramics=22 field (pre-made molded greenware =
painting).
These folk fire in oxidation in the cone 017 (lusters) to cone 6 (low range
stoneware) range. They typically have NO technical knowledge about kilns
and firing and fire totally by the cookbook method. Hence the lack of
commercial =22hobby=22 electric kilns (as opposed to professional electrics
destined for industry) that have reduction capabilities. Most of the small
unit electric kiln companies were heavily involved in this hobby market
first ........ companies like Bailey are relatively new entries in this,
and cater more to the craft potter community.
One of the reasons that you don't see more people doing it is that there
is/was a prevalent myth firmly established in the American ceramic
community that it can't be done. Many teachers categorically tell their
students this supposed fact. It can be done. The =22cost=22 is in =
elements.
If you want to reduce and a fuel kiln is out of the question... then that
is a reasonable cost.
Another reason you don't see it more is that to do it well..... rather than
just as a novelty.... you have to get into modifying your electric kiln.
Technical training in ceramics in this country is pretty lean. So few feel
comfortable with their educational background cutting up a =242000 kiln =
=3Cg=3E.
Also doing this will void the warranty on the kiln (which wasn't designed
for it). Also.... the site requires ventilation for the byproducts of
combustion (not as difficult as for a fuel kiln), which gets again into the
comfort of the person who owns the kiln in more technical issues.
Since Reduction Productions stopped making the Stoker, there has not been
(see below) a commercial unit set up this way available that was warrantied
and had instructions from the manufacturer on HOW to install it properly
and how to operate it.
If you are going to modify your kiln...... contact Euclids Elements and get
elements that are the heaviest guage you can wound for your kiln. Always
do an oxidation firing between reduction firings to renew the oxide coating
on the elements. Have a spare set on hand. Monitor the element condition
like a hawk so you don't get suprised in the middle of a firing.
It appears from my experience (limited) that using the ITC coating on the
elements may extend their life a bit in this environment .... but by
exactly HOW much you would need to do a study with a control kiln without
the coating and repeatedly fire them EXACTLY the same til one has element
failure to compare. I know of no one who has done this. EXACTLY THE SAME.
There is certainly room here to do this type of test on the viability of
ITC coatings in this application. Obviously funding would be needed from
somewhere since it would require two brand new kilns, a lot of monitoring,
and will consume a lot of electricity. (Any independantly wealthy
tech-crazed potters out there that would like to take this on? =3CBg=3E) To=
be
accurate at all, both kilns would have to be computer controlled to ramp
the same cycle, the level of and duration of reduction would need to be
monitored with an oxy probe or CO2 analyzer, and the density and chemical
makeup of the load would be needed to be standardized.
The idea would be to subject BOTH to exactly the same conditions (as
closely as you can control this) and see how the coated elements perform as
compared to the uncoated ones. The element condition could be monitored by
measuring the internal resistance after each firing and graphing it....
taken to the element failure point of one or the other set of elements. If
the ITC coated elements outlasted the uncoated ones (our premise here)...
then the number of additional similar firings til failure would give a good
ballpark figure for expected increased longevity.
The concept isn't hard.
There are too many so-called studies of many technical things published in
the craft ceramics field that are not based on having a good control group
to compare to, and not controlling ALL the important variables. Without
that you frequently don't have enough data from which to draw accurate
conclusions. We do a lot of =22bad science=22. Cause and effect =
relationships
often get drawn that actually are NOT related....but just SEEM to be
related with the limited information available (combined with the inherent
bias of the observer). That is why the scientific and medical community
uses control groups and highly controlled situations when experimenting.
Even they get it wrong sometimes =3Cg=3E.
The electric kiln manufacturers that are SAYING the ITC coatings screw up
the function of the elements in their kilns are in the PERFECT position to
back up their thoughts by publishing (maybe in something like the Journal
of American Ceramic Society) some definitive study data on exactly this
kind of testing... with the control group data right there too. It would
be nice if the folks down at ITC (Alice is a wonderful person and their
customer service is top notch) would publish this type of data in support
of their product for this application.
God..... it would be good if SOMEONE would do this kind of controlled study
for SO MANY aspects of the technical end of what we do. I'd LOVE to see
this type of data available. It would pretty much put to rest all of the
=22it works .... it doesn't work=22, =22it is....it isn't=22 controversy =
that
plagues things like ITC use, salt glazing and chlorine/acid mist
production, barium and other toxin release from glazes, and so on.
This lack of information comes down to money and time, and the fact that
most of us are artists....not scientists =3Cg=3E. While I am cetainly a
techweenie at heart...... I'd far rather spend my time making pots than
doing a scientific study. The tech stuff could easily turn into a full
time job. And I certainly don't have spare thousands lying around to
dedicate to this kind of problem (studio needs a new roof next year and my
daughter is starting college). While I have a little science
background..... that is not who I really am. I assume (dangerous) that one
element or more of this scenario fits most of the other =22tech-types=22 in =
the
craft field.
Maybe we need a technical research fund/endowment set up within NCECA to
provide grants to fund just this type of ACCURATE technical studies???
Maybe our colleges and universities need to look more at the technology
side of the field instead of totally at the aesthetic side? Maybe we need
more interaction with the science departments at our schools? Maybe those
of us who teach need to beef up the technical curriculum for anyone who is
going to be awarded the credentials of a BFA or and MFA?
Maybe there also needs to be a published vehicle (other than the
industry/engineering slanted AmCerSoc Journal) for the dissemination of
technical ceramics information in the US....... with a solid peer review
board looking at manuscripts before publication. (Ceramics Technical comes
to mind as a title...... but that's taken =3Cg=3E.) CM and Clay Times are =
NOT
very good at this aspect, even when they attempt it. They are more general
readership publications. There may be a lot of good studies that are
sitting in places like the library at Alfred that no one other than
students there ever see, because for one thing, there is no venue to
disseminate them through.
Wow...... that got me going=21 Sorry. Off the soapbox.
I vaguely remember seeing an article addressing electric reduction kilns in
Studio Potter magazine many, many years ago. Like maybe back in the early
70's. I may be wrong.... but others on the list may remember more fully.
It wasn't elaborate or detailed... but had some info. It was SOMEWHERE....
but I don't think it was CM.
Other than that, I haven't come across much in the printed world. There
are small references in many ceramics texts, but not a lot of specifics.
Many of the references are old, and very dated (like the mothball
recommendation).
As to general understanding of reduction issues.... see any ceramic
chemistry texts and fuel fired kiln books for info on that general stuff.
The clay and glaze doesn't care what type of kiln it is reduced in =3Cg=3E =
and
the science is the same.
If you want to do it and don't have the technical background to start
=22cutting and pasting=22 your existing electric kiln.... call Axner Pottery
Supply in Florida. They have a combination gas/electric kiln for just this
purpose. It is a new offering in their line.....within the last year I
think. It is not cheap. And it shouldn't be....they gotta get back the
R+D costs and they won't sell a gazillion units.
To do this electric reduction well.... the kiln has to circulate the
reducing agent evenly throughout the chamber. Just popping popsicle sticks
through a spyport TECHNICALLY will cause reduction in an electric... but it
is not as controllable and precise as you might want to have for reliable
results. Or as convenient. As I mentioned before, the best configuration
involves cutting a =22burner port=22 and =22flue=22 and using a tiny gas =
burner
(with guages for monitoring settings).
There might be some Japanese texts that have been translated to English
that have more on this..... but I haven't seen them. Maybe something from
Europe? Anyone know?
Best,
......................john
PS: And as has been said by others... the ITC coatings are supposed to go
on THIN. Very thin. Put it on thick and I would be pretty certain that
you are going to muck up the function of your elements. Clog the element
groove opening much and ........ditto.
John Baymore
River Bend Pottery
22 Riverbend Way
Wilton, NH 03086 USA
603-654-2752
JBaymore=40Compuserve.com
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