Charles on sat 27 dec 03
Dear Friends,
One of my studio associates has been messing with this glaze and today, =
the absolute best case of shivering came out of the kiln. The glaze =
peeled off the porcelain like the shell of of a hard boiled egg. It left =
the same texture too, little bits of the porcelain came off with the =
glaze. Its a simple glaze, started off as a barium blue, but with small =
modifications has become a strontium Stony yellow. He wants to keep the =
stony texture, and believe me it feels like stone..very matt. Any ideas =
how to cure this shivering problem without altering the delightful stony =
surface? Stable is not an issue here..this is for non-food related =
surfaces only.
Kona F-4 Feldspar 28.8
Nepheline Syenite 40.1
Strontium Carbonate 21.5
Silica 9.6
Add:
Black Iron Oxide 6%
The glaze has been applied to #15 Cone 6 Porcelain from Laguna. We fire =
to cone 6 in a ConeArt Oval Kiln with an old fashioned Dawson Sitter,. =
When the kiln sitter shuts off we reset the sitter, turn the timer to 2 =
hours and reset all the dials from "6" to "2" (they go from 1-10) then =
allow the timer to shut down the kiln.
thoughts?
Thank you,
Charles Hughes
www.thecreativeoasis.com
www.thecreativeoasis.com/Hughes/hughes.htm
David Hewitt on sun 28 dec 03
Charles,
Thought that I would just check out the COE for this glaze as the
problem interested me.
Using CeramDat the COE comes out at 4.489 x10-6/oC Linear, English &
Turner.
On the face of this should not be a difficult glaze to avoid either
crazing or shivering. I have no experience of, or data on, the clay body
in question, but wonder if you changed the body to something else you
may solve the problem and still get the glaze effect that you are
seeking.
Another thought has been, has your associate been able to repeat the
shivering or was it a once off freak?
David
In message , Charles writes
>Dear Friends,
>
>One of my studio associates has been messing with this glaze and today, the
>absolute best case of shivering came out of the kiln. The glaze peeled off the
>porcelain like the shell of of a hard boiled egg. It left the same texture too,
>little bits of the porcelain came off with the glaze. Its a simple glaze,
>started off as a barium blue, but with small modifications has become a
>strontium Stony yellow. He wants to keep the stony texture, and believe me it
>feels like stone..very matt. Any ideas how to cure this shivering problem
>without altering the delightful stony surface? Stable is not an issue here..this
>is for non-food related surfaces only.
>
>Kona F-4 Feldspar 28.8
>Nepheline Syenite 40.1
>Strontium Carbonate 21.5
>Silica 9.6
>
>Add:
>
>Black Iron Oxide 6%
>
>
>The glaze has been applied to #15 Cone 6 Porcelain from Laguna. We fire to cone
>6 in a ConeArt Oval Kiln with an old fashioned Dawson Sitter,. When the kiln
>sitter shuts off we reset the sitter, turn the timer to 2 hours and reset all
>the dials from "6" to "2" (they go from 1-10) then allow the timer to shut down
>the kiln.
>
>thoughts?
>
>Thank you,
>
>Charles Hughes
>www.thecreativeoasis.com
>www.thecreativeoasis.com/Hughes/hughes.htm
--
David Hewitt
David Hewitt Pottery
South Wales UK
Web:- http://www.dhpot.demon.co.uk
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