Joyce Lee on wed 15 jul 98
So many of you are asking for the recipe and firing schedule for the
blue and blue-gray celadons that I'm going to put it on Clayart. I used
"Elaine's Blue Celadon" from Tom Coleman's glaze book and fired it in my
8 cu ft (stacking space) Geil fiber kiln. This was the first time it
had been glaze fired since applying ITC. I didn't realy know how to fire
it and the kiln was behaving differently anyway...but I did a light (?)
reduction around 1000 to 1200 F (thus sacrificing carbon trapping for
the shinos), and soaked for 20 minutes in oxidation at ^9. I then
cooled for the first 500 or 600 or more degrees by turning the gas down
in increments, then holding it a bit. I'm fairly sure the top shelf
where the bluest celadon was located didn't get much above ^8. The cone
pack blew up, so I'm not certain but that's usually what happens in that
space when the pyrometer says ^9 to ^9.5 The celadoned pots were loaded
in the middle of the shelves with shinos around them. I did this
because I had a green celadon turn pastel minty green in that location
under those conditions once.(Never could repeat that minty color, but
can get nice gray-greens or just green.) With the ITC the temperature
climbed rapidly even with the door open the first hour, and cracked the
second, on PILOT. No, I don't usually keep the door open since I glaze
a couple days ahead of loading and feel the glaze is dry enough. Is
there something else that should be covered in this description? Oh,
yes, I couldn't wait until the kiln was cooled so opened it to peek
several times. I hope the responses I'm getting doesn't mean this is a
really difficult concept, that I just lucked out, and I'll never be able
to fire blue celadon successfully again. No plugs meant for Tom
particularly although I don't mind plugging, but truth's truth...the
clay was his porcelain from Aardvark. No crazing with this combo. None.
Not even any singing. So there it is, I guess .....Geil,ITC, Coleman
clay and Coleman recipe and all the posts on celadon that I've read on
Clayart, plus trying to follow Mel's instructions to listen to your
kiln. Oughta' go into the advertising business.
Joyce
In the Mojave cleaning the glaze room today, heat or no heat, before
leaving for northern climes. Actually, we have a swamp cooler in there,
thanks to #1 Support Person, so it's not that bad...wish the quail would
come in and cool off.
Wade Blocker on fri 22 sep 00
Verna,
Celadons are generally fired on a porcelain body, to cone 10 in
reduction. The presence of iron changes to the green or celadon color in an
atmosphere where the oxygen is reduced.
However you can get pale greens in an electric kiln at any temperature,
by adding a very small amount of copper carbonate to your base glaze. Mia
in ABQ
John Baymore on fri 5 oct 01
Appropriate? For whom? Art historians develop all sorts of terms within=
their own fields of expertise, but altogether those terms have no relevan=
ce
to discussions in the real world. "Greenwares" is such a term. In studi=
o
ceramics, the appropriate term is "celadon."
Yup.
In fact.... in studio ceramics we already utilize a very similar
term.........
"Hey Bob, put them greenwares sittin' over there into the next bisque
firing."
Best,
..............................john
PS: Always got a good chuckle out of the history books that identified
certain pieces as "yellow celadon" .
John Baymore
River Bend Pottery
22 Riverbend Way
Wilton, NH 03086 USA
603-654-2752 (s)
800-900-1110 (s)
JohnBaymore.com
JBaymore@compuserve.com
John.Baymore@GSD-CO.com
"Earth, Water, and Fire Noborigama Woodfiring Workshop 2002 Dates TBA"=
Lili Krakowski on sun 25 jun 06
Ivor of course is right; that traces of iron and of titanium abound in clays
and other materials essentially considered "untinted". Nigel Woods says a
lot about titanium as an unplanned additive.
However, I long have hoped someone would check out blood. I once read it
was used the way we use gums in glaze. And I have gotten a drop of blood
from a cut on a glazed test tile (call me klutz) and it has fired brown.
So, I have wondered would someone test a bit of blood in a celadon base, as
it would be interesting since the iron would disperse mightily without ball
milling or the like. (Will send recipe for chopped liver to whoever wants).
Also: I long have wondered if someone would test a copper reduction base by
mixing and storing it for a time in a copper vessel. My brother long ago
gave me a copper or brass SOUP LADLE he had gotten in Thailand. And of
course it is "unusable" for anything except scooping bird seed out of its
pail because the copper affects the flavor of any wet food.
Somehow I think color may well have been obtained by rust, verdigris, and
the like, rather than by careful weighing out of colorants.
Lili Krakowski
Be of good courage
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