Ababi on fri 17 may 02
Mastering cone six again>>>>>>>> coloring
Sometimes I think I go too much to details but I find it the only way
to learn.
I send here this recipe will be tested in my next firing, it will not
be soon, as it hard to fill the kiln these days.
.WOO 5
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Cone 6 1220 deg.C. -
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Feldspar Soda F7 28.00
STRONTIUM CARBONATE 11.00
Dolomite 10.00
EPK Kaolin 26.00
SILICA 9.00
ULTROX 11.00
FRIT 3134 4.00
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Seger Weight%
KNO 0.210 4.52%
CaO 0.308 5.92%
MgO 0.181 2.50%
SrO 0.300 10.64%
Al2O3 0.333 11.60%
B2O3 0.054 1.27%
SiO2 2.595 53.37%
ZrO2 0.242 10.19%
K2O 0.005 0.17%
Na2O 0.205 4.35%
Al:Si 7.80
Expan. 7.11
ST 378.83
To one batch I added 3 copper oxide to see the effect of the strontium
To the next batch 3 Red Iron oxide like the basic recipe makes it
yellow
The third batch 1 cobalt oxide to see if the MgO will change to purple
The fourth batch 3 copper carbonate and 3 rutile following the book.
Now I will test each on each glaze on each used by me claybody for
leaching.
I will test the glaze for stability/durability
On each of the claybodies that I might use this glaze.
The big question: Do I have to test for stability/durability of all
four batches?, I mean like they were TOTALLY different glazes or it
would be enough to test the base as a glaze and for leaching only ,all
the glazes.
I know the colorant oxides effect somehow on the fluxing.
Am I right or am I exaggerate?
Ababi Sharon
Kibbutz Shoval- Israel
Mastering Glaze addiction
ababisha@shoval.org.il
http://members4.clubphoto.com/ababi306910/
http://www.milkywayceramics.com/cgallery/asharon.htm
John Hesselberth on fri 17 may 02
on 5/17/02 1:14 AM, Ababi at ababisha@SHOVAL.ORG.IL wrote:
> The big question: Do I have to test for stability/durability of all
> four batches?, I mean like they were TOTALLY different glazes or it
> would be enough to test the base as a glaze and for leaching only ,all
> the glazes.
> I know the colorant oxides effect somehow on the fluxing.
> Am I right or am I exaggerate?
Hi Ababi,
It has been my experience that if leaching of copper is low in a
copper-containing glaze, leaching of the other common colorants will be low
too--that is as long as you don't overload your glaze with one or more of
them. Your levels of cobalt and iron are quite low. I haven't tested this
with some of the less-commonly-used colorants, but, of the ones I have
tested, copper is clearly the most difficult to keep in a glaze. If it will
hold 4-5% copper with minimal leaching, it will hold 1% cobalt or 3% iron.
In fact it would probably hold 2-3% cobalt or 10+% iron.
Regard,
John
Web sites: http://www.masteringglazes.com and http://www.frogpondpottery.com
Email: john@frogpondpottery.com
"Art is not a handicraft, it is the transmission of feeling the artist has
experienced." Leo Tolstoy, 1898
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