Maridel Crawford-Brown on fri 13 sep 96
I am experimenting with a tin white glaze recipe good for Orton cones 5,6,7
and 8 supposedly.
Feldspar 50
Whiting 5
dolomite 25
Chinaclay 20
tin oxide 10
It seemsa fairly straightforward recipe. I have used it on PSH 525 and 519
clays bisqued to Orton cone 05 and 06. I glaze at cone 6 (1200 degrees C.
when the cone goes to the 9 o'clock position). It turns out most often a
chalky stonelike finish although some pieces from the same firing show a
satiny finish which is what I thought it was supposed to be. Today, I got
one piece chalky/stonelike on the side nearest the elements and the side
facing into the kiln was lovely and silky smooth! All the other pieces, no
matter where I had them were chalky.
Am I underfiring?Kiln packed too loosely? (it was fairly open although I
have experimented in a tighter packed kiln and still had mostly chalk).
Any suggestions ot help would be appreciated .
Maridel
Talbott on sat 14 sep 96
Maridel---sounds like the glaze isn't maturing--so fire to cone 8---with
those components you probably could fire to cone 10 and place witness cone
packs 7-9 throughout the kiln so that you know if you have hot and cold
spots in the kiln--which of course you will but you will know how much
difference there is throughout the kiln....Marshall
----------------------------Original message----------------------------
>I am experimenting with a tin white glaze recipe good for Orton cones 5,6,7
>and 8 supposedly.
>Feldspar 50
>Whiting 5
>dolomite 25
>Chinaclay 20
>tin oxide 10
>
>It seemsa fairly straightforward recipe. I have used it on PSH 525 and 519
>clays bisqued to Orton cone 05 and 06. I glaze at cone 6 (1200 degrees C.
>when the cone goes to the 9 o'clock position). It turns out most often a
>chalky stonelike finish although some pieces from the same firing show a
>satiny finish which is what I thought it was supposed to be. Today, I got
>one piece chalky/stonelike on the side nearest the elements and the side
>facing into the kiln was lovely and silky smooth! All the other pieces, no
>matter where I had them were chalky.
>Am I underfiring?Kiln packed too loosely? (it was fairly open although I
>have experimented in a tighter packed kiln and still had mostly chalk).
>Any suggestions ot help would be appreciated .
>Maridel
Marshall Talbott
Pottery By Celia
Route 114
P.O. Box 4116
Naples, Maine 04055-4116
(207)693-6100 voice and fax
clupus@ime.net
Ron Roy on wed 18 sep 96
>----------------------------Original message----------------------------
>I am experimenting with a tin white glaze recipe good for Orton cones 5,6,7
>and 8 supposedly.
>Feldspar 50
>Whiting 5
>dolomite 25
>Chinaclay 20
>tin oxide 10
>
Hi Maridel,
I would recommend either firing it higher or reducing the amount of clay.
Try 19, 18, 17, 16 1nd 15 clay.
I can make it work at the temperature you are firing at but there are
problems - It is probably going to craze on just about any clay and if we
add a frit it will probably be shiney.
If we add any other flux the crazing will increase. Tough choices.
Ron Roy
Toronto, Canada
Evenings, call 416 439 2621
Fax, 416 438 7849
| |
|
