mel jacobson on tue 15 nov 05
industry has many techniques that do not fit the home potter.
injection of gases i think, is one of them.
yes, i have read about many forms of reduction in industry.
i would not want to try it at home.
control of materials is basic and essential. it is not for those
that are just messin about.
coil size is the first consideration. the coils in the average
electric potters kiln are far too fragile, in my mind, to take
the shock of reduction, over and over. so, wear and tear on
the kiln must be considered. industrial electric elements are
thick as your finger, or often larger.
there are no safe and perfect guarantees that electric reduction
is worth the time and effort. itc works for some...but as i have
said...it is not a panacea. again, you have to understand what
you are doing. `pilot error` in the application of itc is classic.
i have seen some real doozies.
and, of course the blame always goes back to the materials...never
the application skill.
i am more and more convinced that a good electric kiln should
be used as intended...oxidation. and, i cannot think of any argument
against that.
i loved the story about the japanese wood firing potter that wanted
to inject water in his kiln at peak temp...he used a balloon full of water...
dropped it in...and SWOOOOSH it blew right back at him..missed his
head by about 6 inches..2000 degree steam bomb. almost dead potter.
if you want a reduction kiln..build a small one. as i tell students all the
time...it takes more work, effort, time and money to do it wrong.
mel
from mel/minnetonka.mn.usa
website: http://www.pclink.com/melpots
Lee Love on tue 15 nov 05
On 2005/11/15 22:01:34, mel jacobson (melpots2@pclink.com) wrote:
> i loved the story about the japanese wood firing potter that wanted
> to inject water in his kiln at peak temp...he used a balloon full of
> water...
;-)
Dry wood is 20% water. Easiest way to add extra water is
by using wet wood. I have sprayed water into the firebox with a
weed sprayer and also into peepholes. Not much different spraying into
the peeps than adding soda solution. Have also tossed ladles of
water into the firebox. Not much happens except backpressure in the
ware chamber. But I have found that wet or green wood is more efficient.
--
Lee Love
in Mashiko, Japan http://mashiko.org
http://seisokuro.blogspot.com/ My Photo Logs
"Where the spirit does not work with the hand, there is no art."
--Leonardo da Vinci
Louis Katz on tue 15 nov 05
********************
Warning: Don't put pure hydrogen into your kiln for reducion.
I think we are going to someday find a commercial kiln in our midst
with a relatively sealed shell and mechanism for the injection of a
gas, namely: Hydrogen5% CO2 95% or some other non explosive reducing
mixture. It may be that it will also require a purge of CO2. With the
stainless shells we are reasonably close to having a relatively good
seal on our kilns and it seems that the seals make this viable. The
light duty elements may change, I doubt these will be cone 10 kilns
unless they are built with some more exotic elements probably adding to
the cost. I also think we will see a return to SiC elements as the cost
of fossil fuels go up and people wanting to fire to cone 10.
I am sure we will see a continued interest in lowfire and midfire
functional ware as $$ pressures on firing force the issue.
As transportation and packaging costs go up we may see a bit of support
for more local production, goo for the Leach School/Small is
Beautiful/support your neighbor kinds of pressures and rewards. At
least I hope this is true.
Warning: Don't put pure hydrogen into your kiln for reducion.
*********************
Louis Katz
Ivory Shack
Island University
Ward Island
Matt MacIntire on tue 15 nov 05
Lee, thank you for your observations on ways of adding water vapor.
Will you please clarify one comment:
Lee Love wrote:
> I have sprayed water into the firebox with a weed sprayer
> and also into peepholes. Not much different spraying into
> the peeps than adding soda solution.
Are you saying that spraying water into the peep holes produced an
effect similar to spraying a soda solution into the peep holes? If that
is your experience, that would a fascinating result.
I have often wondered about the effect of all the water that comes in
with the wood. I always assumed the flashing effects from wood were
more the result of volatile alkalies in the wood. If the water itself
is an agent or catalyst for fluxing the clay surface, that would not be
surprising to me. It would also be a new possibility to investigate. I
always thought that it was the salts...
Frank Gaydos on tue 15 nov 05
There are always exceptions to the rule..
Gertrude and Otto Natlzer used electric kiln firings with a kiln they
brought with them from Austria.
We used to show a movie with them showing how they would glaze fire in
oxidation and then refire adding lots of cuttings from their garden, i.e.,
bamboo leaves, etc.
They would introduce the cuttings into a hole in the door of the kiln below
the bottom shelf.
Some of the works were in saggers.
The kiln elements looked like glo bars. Thick like your finger.
I think it's fair to say they achieved some good glazes.. :>)
Frank Gaydos
Community College of Phila.
------------------------------------------------------------------------------------------
> there are no safe and perfect guarantees that electric reduction
> is worth the time and effort.
Lee Love on wed 16 nov 05
On 2005/11/16 10:09:06, frank.gaydos@verizon.net wrote:
> The kiln elements looked like glo bars. Thick like your finger.
> I think it's fair to say they achieved some good glazes.. :>)
Many people fire in electric reduction here in Japan. They even fire
electric/microwave. (In general, Japan is ahead of America in the
areas of fuel conservation and related pollution control.) They use
charcoal boxes under the kiln or small burners, or like I mentioned last
week, fill a sagger with charcoal. The kilns are different, with
heavy elements. At below link, see the elements and also the small
burners used for reduction:
http://tinyurl.com/dlq9n
--
Lee Love
in Mashiko, Japan http://mashiko.org
http://seisokuro.blogspot.com/ My Photo Logs
"Where the spirit does not work with the hand, there is no art."
--Leonardo da Vinci
Lee Love on wed 16 nov 05
On 2005/11/16 2:12:16, mattm@aacrao.org wrote:
> Are you saying that spraying water into the peep holes produced an
> effect similar to spraying a soda solution into the peep holes? If that
> is your experience, that would a fascinating result.
No. What I was saying, is that I knew it was possible to
introduce a liquid into the peep holes of a hot kiln with a garden
sprayer with no ill effect, because I had done it before with soda
solution.
But what I found to be more effective in my wood kiln
is using wet wood.
Like I mentioned, dry wood is about 20% water.
This is something we loose when we change from wood to gas, oil or
electric, though, it is common to have a water drip with oil ladder
burners.
--
Lee Love
in Mashiko, Japan http://mashiko.org
http://seisokuro.blogspot.com/ My Photo Logs
"Simplicity is the ultimate sophistication."
--Leonardo da Vinci
Ivor and Olive Lewis on wed 16 nov 05
Dear Mel,
You say, <average electric potters kiln are far too fragile, in my mind, to take =
the shock of reduction, over and over. so, wear and tear on the kiln =
must be considered. industrial electric elements are thick as your =
finger, or often larger.>> This may be true. But are you sure it is =
reduction that causes degradation?
As I understand things, Elements are made form Nichrome or Kanthal. The =
metals that contribute to Nichrome form cohesive impermeable oxide =
coatings and their chemistries seem to suggest that these oxides do not =
readily revert to their metallic state. I understand Kanthal contains =
Aluminium. This also produces an oxide that is resistant to reduction.
My experience of Electric Elements is that the stress of thermal cycling =
on their mechanical qualities, especially when they are overheated, that =
has more to do with failure than the nature of the kiln atmosphere and =
its effect on their protective oxide coatings
It is possible to suggest that the nature of clay as it is being bisque =
fired will serve to generate a reducing atmosphere everytime a kiln full =
of clay is fired.
Best regards,
Ivor Lewis.
Redhill,
South Australia.
Arnold Howard on thu 17 nov 05
Over the years I've seen elements that failed due to contamination from the
gases of certain clays. Has anyone else seen that? In one case there was a
reddish deposit on the elements.
Sincerely,
Arnold Howard
Paragon Industries, L.P., Mesquite, Texas USA
ahoward@paragonweb.com / www.paragonweb.com
---------------------
From: "Ivor and Olive Lewis"
My experience of Electric Elements is that the stress of thermal cycling on
their mechanical qualities, especially when they are overheated, that has
more to do with failure than the nature of the kiln atmosphere and its
effect on their protective oxide coatings
Louis Katz on thu 17 nov 05
Nope,
I have seen the vent tubes on BAiley kiln vents die the first time I
fired with corn and rice in my clay. I replaced the aluminum ones with
galvanized steel. I don't fire rice or corn in the electric kilns
anymore. We now have better smoke detectors on the vents and they would
trip the alarms.
I do dry ceramics out in the kiln at 180 degrees F. This is very hard
on the stainless case and screws. It does not seem to be hard on the
elements. They are about five years old now and original, still working
well, on our two electric kilns.
Louis
On Nov 17, 2005, at 7:50 AM, Arnold Howard wrote:
> Over the years I've seen elements that failed due to contamination
> from the
> gases of certain clays. Has anyone else seen that? In one case there
> was a
> reddish deposit on the elements.
Ivor and Olive Lewis on sat 19 nov 05
Dear Arnold Howard,=20
I would not disagree with your observation. But the solution, if you =
seek enlightenment, is to analyse both the clay and the deposit you have =
observed.=20
My suggestion would be that those clays that seem to give this result =
should be examined for Sulphate contamination. Sulphate minerals such as =
Gypsum, Pyrites, common in some natural clays and Barytes, used for =
its anti-scumming qualities, yield Sulphurous gases when they decompose. =
If there is Oxygen in the kiln atmosphere this will change to Sulphur =
Trioxide and Sulphur Dioxide. Both gases are corrosive, SO3 especially =
so. They react with metallic oxides.
Best regards,
Ivor Lewis.
Redhill,
South Australia.
Lee Love on sat 19 nov 05
Lee Love wrote:
> l. The kilns are different, with heavy elements. At below
> link, see the elements and also the small burners used for reduction:
>
> http://tinyurl.com/dlq9n
I added a photo of the price and dimensions plaque to the photos of the
electric kiln:
http://tinyurl.com/dlq9n
--
Lee Love
in Mashiko, Japan http://mashiko.org
http://seisokuro.blogspot.com/ My Photo Logs
"Human subtlety will never devise an invention more beautiful,
more simple or more direct than does Nature,
because in her inventions, nothing is lacking and nothing is superfluous."
--Leonardo da Vinci
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