John Weber on fri 10 may 02
In the past I have usually reduced my body starting at around Cone 08 for a
Cone 10 firing. Then I started eliminating the earlier reduction (except for
shino's or copper reds) and started not reducing until around Cone 05. My
glazes seemed all brighter with the later reduction but there seemed to be a
loss of depth to the glaze. I am about to test a variety of firing schedules
but wanted to ask if anyone on the list is willing to share how they fire in
reduction and still get fairly bright glazes. I know this is mostly glaze
dependent but
I am trying to shorten my search for a firing schedule that will give good
reduction in the glaze, but leave the body as light as possible (white
stoneware body). I will also use the ever popular slow cooling. Any help
would be appreciated. Thanks. John Weber
JODO Pottery
Manakin-Sabot, VA
E-Mail: jodopottery@attbi.com
WEB PAGE: http://jodo96.home.attbi.com
Gail Dapogny on fri 10 may 02
Dear John,
In our very active guild, we fire a 70 cubic foot gas kiln -- reduction --
which has to suit the assorted needs and desires--and demands!-- of 40
members and 30 students.
We used to fire starting reduction at 08, then after an hour, stopping
reduction for a while until about cone 7, somehow with okay results. There
was a general fear of change and a "if it ain't broke, don't fix it"
general attitude, but some of us felt that it was broke! Though largely
ignorant about glaze chemistry, I felt that , with our schedule of
reduction, we had to be missing the melting time of some glaze components
plus other relevant chemical effects.
Anyway....we now do the following with much more satisfactory results:
Start reduction at 012, continue it to the end, trying to get 8 more hours
of firing time before shut-off. Sometimes we have to settle for 7. We
fire to cone 9 over, and 10 well bent. Since it's a large kiln, there is
about a two-cone (cones 8 1/2-10) differentiation from the coolest area to
the hottest (which suits group firing perfectly). We try for an hour soak
at the top temp. Reduction is moderate to slightly heavy throughout, but
never heavy enough to get black smoke, etc.
If I were firing for myself only, I would certainly try cooling such as
Hank suggests, and probably would be pestering beyond patience the wise
ones on the list about other ideas.
Good luck. I'll be eagerly watching for others' suggestions.
----Gail
>In the past I have usually reduced my body starting at around Cone 08 for a
>Cone 10 firing. Then I started eliminating the earlier reduction (except
for
>shino's or copper reds) and started not reducing until around Cone 05.
Gail Dapogny
1154 Olden Road
Ann Arbor, MI 48103-3005
(734) 665-9816
gdapogny@umich.edu
http://www.silverhawk.com/ex99/dapogny (single historical photo - no longer
registered with Silverhawk)
Michele Williams on fri 10 may 02
Subject: Body Reduction - yes or no
Egad! From the corner of my eye, I caught "body reduction - yes or no"--and
voted YES! Dieting is coming on a bit too strong, is it?
You know we use terms that others can take two ways. Ceramics is so much
fun....(sly wink, wink) There's another T-shirt list...
Michele Williams
vince pitelka on fri 10 may 02
> I am trying to shorten my search for a firing schedule that will give good
> reduction in the glaze, but leave the body as light as possible (white
> stoneware body). I will also use the ever popular slow cooling.
John -
Others will have opinions on this, but I do not think that the body
reduction is going to affect the brightness of the glazes, unless you do
excessive body reduction and get carbon coring. I do not think that you are
getting much body reduction at cone 05, because the clay and glazes are
starting to seal (depending on your clay body). I think what you see as
loss of depth in the glaze is because your clay is not reduced, and
therefore you are not getting the iron blooms in the high-fire melt. They
add visual texture, and that might be what you are missing. Not having any
more information this is purely conjecture on my part, but it might be
pertinent.
I like to do body reduction at cone 012 for approximately 45 minutes, and
then a light climbing reduction up to temperature, and finally a 15 minute
oxidation soak to stop all outgassing and let the glazes "heal." And then
you have the whole issue of slow cooling or "firing down," but that is
another topic.
Good luck -
- Vince
Vince Pitelka
Appalachian Center for Crafts
Tennessee Technological University
1560 Craft Center Drive, Smithville TN 37166
Home - vpitelka@dtccom.net
615/597-5376
Work - wpitelka@tntech.edu
615/597-6801 ext. 111, fax 615/597-6803
http://www.craftcenter.tntech.edu/
| |
|
