The Shelfords on thu 27 feb 97
I have always heard that you should NEVER put a glazed piece into an
otherwise bisque firing, so being curious I did just that, and the results
were kind of interesting. It was a varied overlay of three colours of the
same basic glaze (Chappell's Floating Blue) - the tan came out a fairly
bright sulphur yellow, the cinnamon a dirty mustard, the greens remained
more or less green but very dull and greyed out, and the blues went to
shades of mud brown. Then I refired it back up to ^6 and all the original
colours returned! But (and it might be my imagination) I THINK the colours
came back with more intensity than before.
Does anyone know or can they guess what was happening here? What is it
about bisque fumes that would have that effect? Would the slightly greater
intensity of colour later be a possible consequence of those fumes, or just
of the refiring? I LOVE it when something weird happens!
Veronica on Thetis
Deb & Curt Maxwell on fri 28 feb 97
Now I am confused. Isn't bisque as a general rule done at cone 04 or so?
That would mean a great difference between the first bisque firing and the
second firing at cone 6 which I assume would make a difference in how the
glaze responded. Someone technical please respond!
deb clay in snowy grey Calgary
----------
From: Ceramic Arts Discussion List on behalf of The Shelfords
Sent: Thursday, February 27, 1997 4:51 AM
To: Multiple recipients of list CLAYART
Subject: glazed pieces in a bisque firing
----------------------------Original message----------------------------
I have always heard that you should NEVER put a glazed piece into an
otherwise bisque firing, so being curious I did just that, and the results
were kind of interesting. It was a varied overlay of three colours of the
same basic glaze (Chappell's Floating Blue) - the tan came out a fairly
bright sulphur yellow, the cinnamon a dirty mustard, the greens remained
more or less green but very dull and greyed out, and the blues went to
shades of mud brown. Then I refired it back up to ^6 and all the original
colours returned! But (and it might be my imagination) I THINK the colours
came back with more intensity than before.
Does anyone know or can they guess what was happening here? What is it
about bisque fumes that would have that effect? Would the slightly greater
intensity of colour later be a possible consequence of those fumes, or just
of the refiring? I LOVE it when something weird happens!
Veronica on Thetis
The Shelfords on mon 3 mar 97
>Now I am confused. Isn't bisque as a general rule done at cone 04 or so?
>That would mean a great difference between the first bisque firing and the
>second firing at cone 6 which I assume would make a difference in how the
>glaze responded. Someone technical please respond!
>deb clay in snowy grey Calgary
>
I'm sorry, I put that badly. I should have made it clear that I was
talking about a re-firing - a piece already glaze fired to maturity at ^6,
and then put into a kiln with greenware being taken to bisque (^06). This
changed the original colours, then the original colours returned, but more
intensely, when refired again up to ^6. I did it because of reading about
some of Lana Wilson's work, not that she suggested throwing pieces into a
bisque firing! But she suggested refiring to bisque temperature. But I
didn't have enough pieces to test or a free kiln at the time, so I tried it
in a regular bisque firing instead.
Veronica
>----------------------------Original message----------------------------
>I have always heard that you should NEVER put a glazed piece into an
>otherwise bisque firing, so being curious I did just that, and the results
>were kind of interesting. It was a varied overlay of three colours of the
>same basic glaze (Chappell's Floating Blue) - the tan came out a fairly
>bright sulphur yellow, the cinnamon a dirty mustard, the greens remained
>more or less green but very dull and greyed out, and the blues went to
>shades of mud brown. Then I refired it back up to ^6 and all the original
>colours returned! But (and it might be my imagination) I THINK the colours
>came back with more intensity than before.
>
>Does anyone know or can they guess what was happening here? What is it
>about bisque fumes that would have that effect? Would the slightly greater
>intensity of colour later be a possible consequence of those fumes, or just
>of the refiring? I LOVE it when something weird happens!
>
Veronica Shelford
e-mail: shelford@island.net
s-mail: P.O. Box 6-15
Thetis Island, BC V0R 2Y0
Tel: (250) 246-1509
"Gullibility is the key to all adventures. The greenhorn is the ultimate
victor in all things; it is he who gets the most out of life." Chesterton
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