Overall's on sun 5 aug 07
If raku is fired 1650 to 1800 typically,
and if present clay using is stoneware,
why couldn't the work be fired to cone 10 with cone 10 glazes
and when it cools to the raku range,
be taken out and reduced like regular raku?
Kim Overall
http://www.kimoverall.com/events.html
Dannon Rhudy on sun 5 aug 07
Kim asked:
> If raku is fired 1650 to 1800 typically,
> and if present clay using is stoneware,
> why couldn't the work be fired to cone 10 with cone 10 glazes
> and when it cools to the raku range,
> be taken out and reduced like regular raku?
Generally speaking, clays that have been fired to
cone 10 are essentially vitrified. Because they are
vitrified, they will not absorb carbon, so while you
could do what you suggest, the results would not
look like low-fire raku. There are other ways to
achieve similar surfaces at high temps, but they
won't be the same, and they're troublesome.
Incidentally, when you open your regular kiln
"at raku temperatures", the odds are pretty good
that you'll crack some shelves, not to mention
a brick or so.
regards
Dannon Rhudy
Lee Love on sun 5 aug 07
On 8/5/07, Overall's wrote:
> why couldn't the work be fired to cone 10 with cone 10 glazes
> and when it cools to the raku range,
> be taken out and reduced like regular raku?
This technique was developed soon after raku in the 16th.(another
technique inspired by Rikyu and tea ceremony.) It is called Hikidashi
and is used for iron saturated Seto Guro/black. Hikidashi means
"drawer." You need more heat protection at these temps.
My friend Doug Black specialize in the technique. He has a bell
fiber kiln he uses to fire it with. Lifts the bell with a counter
weight:
http://www.unm.edu/~ceschiat/hikidashi.htm
interview with Doug:
http://www.unm.edu/~ceschiat/DBinterview.htm
--
Lee in Mashiko, Japan
Minneapolis, Minnesota USA
http://mashikopots.blogspot.com/
"To affect the quality of the day, that is the highest of arts." -
Henry David Thoreau
"Let the beauty we love be what we do." - Rumi
Lee Love on sun 5 aug 07
On 8/5/07, Overall's wrote:
> Wow Lee!
>
> That's pretty interesting.
> I'm not too keen on the 'all black is beautiful' hikidashi,
> and the turquoise appears undistinguishable from low fire raku.
> Are these the only typical colors (except or the white clay slip)?
Doug's last name is Black. Haha. So he has an affinity.
If you look at Aaron's sculptural work, you can see yellow and
red too. These are all pulled and cool in oxidation.
There are reduction effects on highfire as you can see in high
fire work where charcoal is introduced at the end of the firing.
Possibilities are endless. Just have to experiment. I think
a well insulated fiber bell/tophat kiln is essential for hikidashi,
and good protective equipment. Not for the faint of heart.
Doug's kiln is very efficient, which is important in Japan where LPG
is more expensive.
--
Lee in Mashiko, Japan
Minneapolis, Minnesota USA
http://mashikopots.blogspot.com/
"To affect the quality of the day, that is the highest of arts." -
Henry David Thoreau
"Let the beauty we love be what we do." - Rumi
Vince Pitelka on sun 5 aug 07
Kim Overall wrote:
> If raku is fired 1650 to 1800 typically,
> and if present clay using is stoneware,
> why couldn't the work be fired to cone 10 with cone 10 glazes
> and when it cools to the raku range,
> be taken out and reduced like regular raku?
Kim -
I hope you are continuing to do those incredible surface carvings I saw i=
n
Texas a year and a half ago. You've got the touch.
But regarding your question, Dannon is right about possible damage to you=
r
kiln shelves and other pots. Just to rephrase what she said, high-fired
clay is vitrified and is far less "flexible" than a sintered, porous
low-fired clay, and thus has far less thermal-shock resistance. Even if
you wait until the kiln reaches low-fire temperatures before removing the
ware, there would be a risk of dunting.
I am curious as to why you would want to make high-fired ware look like
raku? I mean, raku is an evolving medium that has changed quite a bit in
its evolution in North American studio pottery, but if you are to claim
any adherence and lineage from Japanese raku, then "high-fired raku" is a=
n
oxymoron. There ain't no such thing.
That said, you could certainly glaze high-fired ware with a glaze that
will purposefully craze, and then after the glaze-firing soak it in an
India ink solution, alternately heating up and cooling the mix in order t=
o
encourage the ink into the crackles. This is essentially what happens
over time with old ceramic objects - discoloration from tea and other foo=
d
products seeps into the crazing cracks and impacts permanently. That
effect would have no connection to raku, but it might be closer to what
you are looking for.
Good luck -
- Vince
--=20
Vince Pitelka
Appalachian Center for Craft
Tennessee Technological University
vpitelka@dtccom.net
http://iweb.tntech.edu/wpitelka/
Lee Love on sun 5 aug 07
On 8/5/07, Lee Love wrote:
> On 8/5/07, Overall's wrote:
>
> > why couldn't the work be fired to cone 10 with cone 10 glazes
> > and when it cools to the raku range,
> > be taken out and reduced like regular raku?
Kim,
The other reason to pull pots at high temp is that you keep
from putting the kiln furniture through quarts inversion.
Also, is you pull at cooler temps, the glazes would not be as
reactive to any reduction materials you may put them in.
My latest experiments has been putting refire pots in my wood
kiln, under the grates in the firebox. They become covered with
coals and look similar to yohen fired ware, where charcoal is
introducing into the firing chamber. They can be left in until the
kiln is cool, or they can be raked out before closing up the kiln.
Actually, it is very similar to pulling pots and then introducing them
to reduction materials, except you are not putting the clay body
through as much shock because there is no quick cooling.
Because of these experiments, I am going to build a small
pizza oven that I can used the bottom of to fire to cone 10 with
refire pots in the fire chamber using an lpg burner. I will
introduce charcoal at the end and then close up all the holes.
Shouldn't smoke too much (will try it in the countryside first.)
When I do pizza or bread, I will just get it up to temp with wood and
stop stoking.
Will share tests when I do it.
--
Lee in Mashiko, Japan
Minneapolis, Minnesota USA
http://mashikopots.blogspot.com/
"To affect the quality of the day, that is the highest of arts." -
Henry David Thoreau
"Let the beauty we love be what we do." - Rumi
John Britt on sun 5 aug 07
Kim,
I have tried this and there is one problem. The body seals over and you
can't get the smoke to soak into the body so you have pasty looking ware.
I wanted more durable ware and settled on firing the bisque to cone 1
(where my body was still porous enough to absorb the smoke) and then fired
the Raku as usual.
Hope it helps,
John Britt
www.johnbrittpottery.com
Lee Love on sun 5 aug 07
On 8/5/07, John Britt wrote:
> Kim,
>
> I have tried this and there is one problem. The body seals over and you
> can't get the smoke to soak into the body so you have pasty looking ware.
> I wanted more durable ware and settled on firing the bisque to cone 1
> (where my body was still porous enough to absorb the smoke) and then fired
> the Raku as usual.
>
John,
It might be better to introduce charcoal or saggering in it, rather
than pulling the pots if you want a heavy reduction effect. The tea
bowls at the top of the page below were refired in my firebox, under
the grates:
http://mashikopots.blogspot.com/
--
Lee in Mashiko, Japan
Minneapolis, Minnesota USA
http://mashikopots.blogspot.com/
"To affect the quality of the day, that is the highest of arts." -
Henry David Thoreau
"Let the beauty we love be what we do." - Rumi
Lee Love on mon 6 aug 07
On 8/6/07, Overall's wrote:
> I've been enlightened everyone! Several "ah-soooo" moments. Especially the wisdom of
>cracking shelves and great balls of fire smokin' shoes. I'm not THAT
desirous of attempting
>it right now.
Please don't let the timid frighten you out of exploration.
All it takes is a little common sense.
You might consider something that is popular in Mashiko:
High fired, charcoal saggering. I wouldn't do it in an American
electric kiln, but you could do it in a well insulated fiber kiln or a
regular gas kiln.
--
Lee in Mashiko, Japan
Minneapolis, Minnesota USA
http://mashikopots.blogspot.com/
"To affect the quality of the day, that is the highest of arts." -
Henry David Thoreau
"Let the beauty we love be what we do." - Rumi
David Woof on mon 6 aug 07
True story, caution: 1650 F and cone 9 are different animals. Take extra
caution accordingly.
Ryoji Koie was doing a high fire raku at UWLaCrosse some years ago using
locally dug clay. He was fully protected except for his Tennis shoes
protruding from beneath the gear. When we opened the front loading kiln
door, with cone 9 down, his shoes burst into flames.
David
_________________________________
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David Woof Studio
Clarkdale, Arizona
Ph. 928-821-3747
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John Britt on mon 6 aug 07
Lee,
I saw your pots and they are beautiful!
Congratulations on your Fellowships too!
John Britt
www.johnbrittpottery.com
Overall's on mon 6 aug 07
I've been enlightened everyone! Several "ah-soooo" moments. Especially the wisdom of cracking shelves and great balls of fire smokin' shoes. I'm not THAT desirous of attempting it right now.
Vince, from your October 2006 workshop, I've delved into my first coiled pot which turned into my first figurative head. He's been bisqued and awaiting the final firing. Still carving, but I'm really enjoying handbuilding more than I thought I ever would thanks to your workshop.
THANKS YA'LL!
Kim Overall
http://www.kimoverall.com/events.html
Deborah Thuman on tue 7 aug 07
I'll take a stab at this one.
I know commercial low-fire raku clay has about a half a beach worth of
sand in it because the clay has to take a huge temperature shock. The
piece is removed from the kiln when the piece is glowing red hot. Then
the piece travels through the air to a container with combustible
material and is deposited in the material. Once the material is in
flames, the cover is put on for the reduction part of the firing.
I know regular low fire clay is not good for raku because it can't take
the huge temperature change. I think, but don't know, that the raku
glazes are also formulated specifically to take the huge temperature
change and to do something magical in a reduction firing.
Corningware was designed to go from freezer to stovetop so I would
guess that a high fire clay could be adapted to tolerate the
temperature shock. I would also guess (the chemistry and science of
ceramics is NOT my strong point) that the regular high fire glazes
would have to be altered as well to tolerate the temperature shock.
This could be an interesting experiment. How do you plan on getting the
pieces out of the kiln? I'd think you would need some very good
protective clothing if you're planning on opening the door of the kiln
and getting within tong distance of a piece.
Deb
http://debthumansblog.blogspot.com/
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