F. Melville on thu 11 sep 97
Kaye,
In 19th century Bristol, England, less toxic zinc oxide was used to
replace raw lead as a flux in the cone 4-6 range, hence the name "Bristol
Glaze". These glazes were more resistant to abrasion, weathering and
chemical attack and gave good hues of blue and green. Here are a couple of
recipes taken from the CM handbook 'Glaze Projects by Richard Behrens'. I
have not tried either of them myself.
Bristol Glaze VIII cone 6, opaque mottled
Zinc oxide 12
Nepheline syenite 40.5
Lithium carbonate 4.5
Kaolin 7.8
Flint 35.2
Bristol Glaze X cone 6, fairly clear and bright
Zinc oxide 6.9
Pemco frit 25 27.3
Lithium carbonate 3.2
Kaolin 9.3
Calcined kaolin 7.6
Flint 45.7
Francoise
F. Melville
Indalo Pottery
P.O. Box 95
Port Edward, B.C.
V0V 1G0
Canada
Email:fmelvill@mail.kaien.com
http://members.tripod.com/~indalopottery
=?ISO-8859-1?Q?G=FCnter_Hermans?= on tue 3 sep 02
hello everyone,
has anyone got any idea why, after the oxidation firing of my white
Bristol glaze, we are getting pink flecks in the bottom of our bowls and
jugs? there is also a pale-pink, thin residue coating.
there is tin, dolomite and talcum in the recipe. perhaps the magnesium
in the dolomite/ talcum is the problem?
if anyone has had the same problem and been able to solve it, we'd
really appreciate some help.
the glaze recipe is:
whiting 1.38
kaolin 8.30
zinc oxide 6.64
quartz 19.36
dolomite 8.85
nepheline syenite 35.40
talc 9.96
tin oxide 6.27
bentonite 3.84
greetings and thanks
from bavaria, germany
guenter and niki
--
H E R M A N S - K E R A M I K tel. +49 (0)8728-675
fraundorf 30 fax +49 (0)8728-910126
84335 mitterskirchen www.hermans-keramik.de
germany
Dale Neese on tue 3 sep 02
Guenter, I suspect that the tin oxide in your Bristol white glaze is
attracting some chrome oxide from another glaze or an underglaze stain that
contains chrome. Chrome is released into the atmosphere of the kiln during
firing and can possibly travel over and settle on other pots in the kiln.
White glazes containing tin oxide are affected the most and will tend to
have a pink cast to them. You may not see it on kiln walls and furniture but
can remain in the kiln and appear again in future firings.
Dale Tex
Ababi on wed 4 sep 02
Copper Too
Ababi
---------- Original Message ----------
>Guenter, I suspect that the tin oxide in your Bristol white glaze is
>attracting some chrome oxide from another glaze or an underglaze stain that
>contains chrome. Chrome is released into the atmosphere of the kiln during
>firing and can possibly travel over and settle on other pots in the kiln.
>White glazes containing tin oxide are affected the most and will tend to
>have a pink cast to them. You may not see it on kiln walls and furniture but
>can remain in the kiln and appear again in future firings.
>Dale Tex
>______________________________________________________________________________
>Send postings to clayart@lsv.ceramics.org
>You may look at the archives for the list or change your subscription
>settings from http://www.ceramics.org/clayart/
>Moderator of the list is Mel Jacobson who may be reached at melpots@pclink.com.
Johanna De Maine on wed 4 sep 02
Hello Guenter and Niki
The question comes to mind whether you had something containing chrome o=
r
have fired a chrome glaze in the past. Chrome is volatile and because y=
our
glaze has tin in it, it could be causing a chrome/tin pink reaction.
regards
Johanna De Maine
----- Original Message -----
From: "G=FCnter Hermans"
To:
Sent: Wednesday, September 04, 2002 7:38 AM
Subject: Bristol glaze
> hello everyone,
> has anyone got any idea why, after the oxidation firing of my white
> Bristol glaze, we are getting pink flecks in the bottom of our bowls an=
d
> jugs? there is also a pale-pink, thin residue coating.
> there is tin, dolomite and talcum in the recipe. perhaps the magnesium
> in the dolomite/ talcum is the problem?
>
> if anyone has had the same problem and been able to solve it, we'd
> really appreciate some help.
> the glaze recipe is:
> whiting 1.38
> kaolin 8.30
> zinc oxide 6.64
> quartz 19.36
> dolomite 8.85
> nepheline syenite 35.40
> talc 9.96
> tin oxide 6.27
> bentonite 3.84
>
> greetings and thanks
> from bavaria, germany
> guenter and niki
>
> --
> H E R M A N S - K E R A M I K tel. +49 (0)8728-675
> fraundorf 30 fax +49 (0)8728-910126
> 84335 mitterskirchen www.hermans-keramik.de
> germany
>
>
_________________________________________________________________________=
___
__
> Send postings to clayart@lsv.ceramics.org
>
> You may look at the archives for the list or change your subscription
> settings from http://www.ceramics.org/clayart/
>
> Moderator of the list is Mel Jacobson who may be reached at
melpots@pclink.com.
Johanna De Maine on thu 5 sep 02
Hi Ababi
To my knowledge copper does volatilize but does not produce pink spots in an
oxidation firing in an electric kiln
regards
Johanna De Maine
----- Original Message -----
From: "Ababi"
To:
Sent: Wednesday, September 04, 2002 3:06 PM
Subject: Re: Bristol glaze
> Copper Too
> Ababi
> ---------- Original Message ----------
>
> >Guenter, I suspect that the tin oxide in your Bristol white glaze is
> >attracting some chrome oxide from another glaze or an underglaze stain
that
> >contains chrome. Chrome is released into the atmosphere of the kiln
during
> >firing and can possibly travel over and settle on other pots in the kiln.
> >White glazes containing tin oxide are affected the most and will tend to
> >have a pink cast to them. You may not see it on kiln walls and furniture
but
> >can remain in the kiln and appear again in future firings.
> >Dale Tex
>
>
>___________________________________________________________________________
___
> >Send postings to clayart@lsv.ceramics.org
>
> >You may look at the archives for the list or change your subscription
> >settings from http://www.ceramics.org/clayart/
>
> >Moderator of the list is Mel Jacobson who may be reached at
melpots@pclink.com.
>
>
____________________________________________________________________________
__
> Send postings to clayart@lsv.ceramics.org
>
> You may look at the archives for the list or change your subscription
> settings from http://www.ceramics.org/clayart/
>
> Moderator of the list is Mel Jacobson who may be reached at
melpots@pclink.com.
William Lucius on thu 5 sep 02
You mentioned that you fire the glaze in oxidation. To what
temperature/cone are you firing the glaze?
William A. Lucius, Board President
Institute for Archaeological Ceramic Research
845 Hartford Drive
Boulder, CO 80305
iacr@msn.com
_________________________________________________________________
MSN Photos is the easiest way to share and print your photos:
http://photos.msn.com/support/worldwide.aspx
=?ISO-8859-1?Q?G=FCnter_Hermans?= on thu 5 sep 02
about 1280°C-1290°C
William Lucius schrieb:
> You mentioned that you fire the glaze in oxidation. To what
> temperature/cone are you firing the glaze?
>
>
>
> William A. Lucius, Board President
> Institute for Archaeological Ceramic Research
> 845 Hartford Drive
> Boulder, CO 80305
> iacr@msn.com
>
>
> _________________________________________________________________
> MSN Photos is the easiest way to share and print your photos:
> http://photos.msn.com/support/worldwide.aspx
>
> ______________________________________________________________________________
>
> Send postings to clayart@lsv.ceramics.org
>
> You may look at the archives for the list or change your subscription
> settings from http://www.ceramics.org/clayart/
>
> Moderator of the list is Mel Jacobson who may be reached at
> melpots@pclink.com.
>
--
H E R M A N S - K E R A M I K tel. +49 (0)8728-675
fraundorf 30 fax +49 (0)8728-910126
84335 mitterskirchen www.hermans-keramik.de
germany
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