Jeff Lawrence on sat 23 mar 02
Cor was asking about air bubbles in a Jun glaze
Hi Cor,
I seem to remember reading in a paper by Pamela Vandiver that
Chun (also known as Jun) glazes achieve their look by a variety
of optically significant factors including air bubbles,
undissolved bits of glaze minerals, phase separations, crystal
formation, and a couple others I can't recall.
I don't know the glaze you refer to, but a slower cooling cycle
ought to favor phase separations and crystal formation, while
allowing some bubbles to escape. Of course, the look might not
be right.
Maybe you could take a page from computer programmers -- they
say, it's not a bug -- it's a feature!
Best,
Jeff
Jeff Lawrence
jml@cybermesa.com
Cor Duijnker on sat 23 mar 02
Hello,
I want to use the beautiful Michael Bailey's glaze JB1. Cone 6. ox
There are air bubbles in my glaze and I can't get them out.
As the glaze is from a book recipe,I assume that the glaze is well =
tested.
Is there someone with a good suggestion to get this glaze right?
Cor Duijnker
J.v.Damweg 47
8411XB Jubbega
0516-462746
e-mail c.j.duijnker@chello.nl
Lee Love on sun 24 mar 02
Phosphorous Pentoxide - P2O5, is responsible for the bubbles in the original
Chun glazes. It can be introduced from ashes or bone ash. P2O5 opacifies by
suspending small gas bubbles in the glaze. These bubbles act like a prism
giving the same type of blue in the glaze you see in the blue sky.
Most Chuns are primarily feldspar so application without drips or runs
is pretty difficult: It dries on the bisque quickly. Wetting the bisque
first & using a thick glaze helps. I am experimenting with copper slip inlay
decoration under chun blue, related to the copper decoration of Korean Yi
dynasty work.
One of my favorite pieces I first saw in Chicago, at a traveling
exhibition of Korean work on loan from a museum in Osaka. It is a copper
decorated jar, the image of a Tiger. I saw the same piece in Osaka on my last
visit to Japan (before I move here) in '98.
--
Lee In Mashiko, Japan Ikiru@kami.com
"We can only wait here, where we are in the world, obedient to its processes,
patient in its taking away, faithful to its returns. And as much as we may
know, and all that we deserve of earthly paradise will come to us."
Wendell Berry , Full Quote: http://www1.ocn.ne.jp/~ikiru/berry.html
Hank Murrow on sun 24 mar 02
> Phosphorous Pentoxide - P2O5, is responsible for the bubbles in the original
>Chun glazes. It can be introduced from ashes or bone ash. P2O5 opacifies by
>suspending small gas bubbles in the glaze. These bubbles act like a prism
>giving the same type of blue in the glaze you see in the blue sky.
>
> Most Chuns are primarily feldspar so application without drips or runs
>is pretty difficult: It dries on the bisque quickly. Wetting
>the bisque
>first & using a thick glaze helps. I am experimenting with copper slip inlay
>decoration under chun blue, related to the copper decoration of Korean Yi
>dynasty work.
>
>Lee In Mashiko, Japan Ikiru@kami.com
>
And Hank in Eugene suggests:
That if you want P2O5 in your wood ash......try to select ash
from fruit trees, and try to select small branches....there is where
the highest concentration of P2O5 will be found. There is very little
of it in woods like pine, cedar, or oak. Fruit needs P2O5 to
develop.......so look for fruit wood ash. Maybe plum, Lee?
Today is the last day of Ian's workshop. Going to the little
C/10 kiln to unload in minutes. Then to Portland monday to have
breakfast with Victoria Christen and Gail Nichols after a visit to
her show there. Ian returns later in the week to fire the pots we
made in the studio together. Great company. Exciting times!
Cheers, Hank
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