Jessi Elert on tue 25 apr 00
Hi there. I just joined this listserv and hope not every
day is as email crazy as this day! I just got 30 new emails
in 5 minutes!
Anyways, I have a question about my glazes. I recently took
my 4th ceramics class and this is the first time ever my
glaze has bubbled. I am used to cone 10 glazes, but at this
class we're using store-bought low-fire glazes. (cone 06 I
believe) A lot of my pots have come out of the kiln with
bubbles/blisters. I tried to re-fire the pots slowly and at
the same temperature, but they look the same...still
blistered. What can I do to remedy this? My friend thinks
we should re-fire at one cone hotter. Does this work? Will
the glaze run off the pots? Do we need grind the bubbles
and apply more glaze before we re-fire? Thanks for your
help!
Here is what her book said:
"Cratered or bubbled glaze. In this glaze error, the
craters develop as a result of body gases erupting through
the glaze and
'freezing' as the kiln cools. The condition is caused by
underfiring. To salvage such a piece, grind down the high
spots, apply a thin coat of glaze and refire to a higher
temperature."
"Pinholes. Pinholes are tiny indentations in the
glaze surface which are generally no larger than the point
of a pin. This fault may occur in any type of glaze, and is
caused by underfiring. To salvage a piece, refire at a
higher temperature."
--
===================================================
Jessi Elert Milwaukee, WI USA
Web Page: http://www.geocities.com/CollegePark/5862/
AND: http://www.CeramicsForSale.com
(C) Copyright 2000 Jessi Elert
===================================================
Cindy Strnad on wed 26 apr 00
Jessi,
How high was the bisque fired? For low-fire glazes, the bisque firing should
be a cone or two hotter than the glaze firing. Another thing you might
consider is contacting the maker of the glazes. They would likely be able to
help quite a lot.
Cindy Strnad
earthenv@gwtc.net
Earthen Vessels Pottery
RR 1, Box 51
Custer, SD 57730
Jan McQueary on wed 26 apr 00
Did you fire your cone 06 glaze in a bisque load along with raw pots?
Many cone 06 glazes will bubble from the gases or moisture given off by
other pots being bisqued simultaneously in the same kiln.
Jan McQueary
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Rikki Gill on wed 26 apr 00
Hi Jessi Some potters also put a blanket of kwool over the top of the
kiln just when it goes off to soak for a few minutes. I think maybe about
15. Also you can go.over the freshly applied glaze with your fingertips to
eliminate an orange peel texture and pinholing.
---Original Message-----
From: Jessi Elert
To: CLAYART@LSV.UKY.EDU
Date: Tuesday, April 25, 2000 12:13 PM
Subject: Bubbling/Blisters
>----------------------------Original message----------------------------
>Hi there. I just joined this listserv and hope not every
>day is as email crazy as this day! I just got 30 new emails
>in 5 minutes!
>
>Anyways, I have a question about my glazes. I recently took
>my 4th ceramics class and this is the first time ever my
>glaze has bubbled. I am used to cone 10 glazes, but at this
>class we're using store-bought low-fire glazes. (cone 06 I
>believe) A lot of my pots have come out of the kiln with
>bubbles/blisters. I tried to re-fire the pots slowly and at
>the same temperature, but they look the same...still
>blistered. What can I do to remedy this? My friend thinks
>we should re-fire at one cone hotter. Does this work? Will
>the glaze run off the pots? Do we need grind the bubbles
>and apply more glaze before we re-fire? Thanks for your
>help!
>
>Here is what her book said:
> "Cratered or bubbled glaze. In this glaze error, the
>craters develop as a result of body gases erupting through
>the glaze and
>'freezing' as the kiln cools. The condition is caused by
>underfiring. To salvage such a piece, grind down the high
>spots, apply a thin coat of glaze and refire to a higher
>temperature."
> "Pinholes. Pinholes are tiny indentations in the
>glaze surface which are generally no larger than the point
>of a pin. This fault may occur in any type of glaze, and is
>caused by underfiring. To salvage a piece, refire at a
>higher temperature."
>--
>===================================================
>Jessi Elert Milwaukee, WI USA
>Web Page: http://www.geocities.com/CollegePark/5862/
>AND: http://www.CeramicsForSale.com
>(C) Copyright 2000 Jessi Elert
>===================================================
>
DeBorah Goletz on thu 27 apr 00
Jessi - I've seen some commercial low fire clear glazes bubble as a result
of being applied to damp bisqueware (when students rinsed their pots clean
before glazing). This doesn't make sense to me, but at least the problem
could be avoided by allowing the pots to dry before glazing. Try the
archives for more information.
Best,
DeBorah Goletz
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