Ababi on fri 19 apr 02
So, When the dining room lady offered me to make 50 cups,kind of tea
bowls,I told her that I learn now from a new book how to make safer
glazes. She was willing to wait, and I am willing to ask anther question
Or two.
Glazes like these ones as clear, assuming that it fits my claybody. Can
it be a liner glaze?
This one was built out of Bailey's recipe into the J&R limits
FOODSAFE
,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,
Cone 6 1201 deg.C. -
,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,
FELDSPAR SODA F7/SE 3.35
ENGLISH KAOLIN CC31 22.10
Dolomite 12.86
ZINC OXIDE 3.58
Calcium Carbonate 4.01
SILICA 37.25
FRIT A 2120 p 16.85
,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,
Seger Weight%
KNO 0.268 6.31%
CaO 0.415 8.49%
MgO 0.182 2.68%
ZnO 0.135 4.01%
Al2O3 0.273 10.15%
SiO2 3.115 68.33%
TiO2 0.001 0.02%
K2O 0.021 0.71%
Na2O 0.247 5.60%
Al:Si 11.42
Expan. 7.38
ST 360.18
,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,
In the next one the B2O3 is higher than suggested
Can it still be a good liner?
CLEAR HUDDLESTON FOODSAFE
,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,
Cone 6 1201 deg.C. -
,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,
FRIT 3134 48.00
ENGLISH KAOLIN CC31 28.00
SILICA 20.00
ZINC OXIDE 4.00
,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,
Seger Weight%
KNO 0.283 5.94%
CaO 0.554 10.02%
MgO 0.004 0.06%
ZnO 0.158 4.15%
Al2O3 0.320 10.49%
B2O3 0.513 11.51%
SiO2 2.984 57.81%
TiO2 0.001 0.03%
K2O 0.027 0.82%
Na2O 0.256 5.12%
Al:Si 9.34
Expan. 7.39
ST 326.96
Comment: Out of another recipe:
With 3134 ...50
EPK 30
Silica 20
Seger Weight%
KNO 0.337 6.23%
CaO 0.657 10.47%
MgO 0.005 0.06%
Al2O3 0.390 11.27%
B2O3 0.608 12.02%
SiO2 3.514 59.92%
TiO2 0.001 0.03%
K2O 0.033 0.88%
Na2O 0.304 5.35%
Al:Si 9.01
Expan. 7.33
ST 322.21
Can this be a liner, It fits beautiful!
Not to tire you:
If the Silica alumina is fine, and I use it as clear, Or white. must
the other materials in these limits?
What do you think, about it,Ivor Lewis?
Ababi Sharon
Kibbutz Shoval- Israel
Glaze addict
ababisha@shoval.org.il
http://members4.clubphoto.com/ababi306910/
http://www.milkywayceramics.com/cgallery/asharon.htm
John Hesselberth on fri 19 apr 02
on 4/19/02 4:17 AM, Ababi at ababisha@shoval.org.il wrote:
> So, When the dining room lady offered me to make 50 cups,kind of tea
> bowls,I told her that I learn now from a new book how to make safer
> glazes. She was willing to wait, and I am willing to ask anther question
> Or two.
> Glazes like these ones as clear, assuming that it fits my claybody. Can
> it be a liner glaze?
> This one was built out of Bailey's recipe into the J&R limits
> FOODSAFE
> ,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,
>
Hi Ababi,
I don't see any problem with using any of those 3 glazes as a liner. There
are really no materials of concern in the first place so it is mainly a
question of durability. Your 3 glazes should be quite durable. I have
never found high boron to be a negative to durability. There are some
literature references that say it might be, but I just haven't seen it. In
fact Waterfall Brown has an extremely high level of boron and it tested to
be very stable.
As you can tell from reading the book, while we give a set of limit formulas
in the Appendix, we really think the 4 rules (below for those who don't have
the book) we developed are more likely to result in durable glazes than
staying within limits. Said another way, the limits on silica and alumina
make sense--those on fluxes don't make much difference to durability as long
as you get the glaze thoroughly melted during firing. That is what you need
to focus on: 1) enough silica 2) enough alumina 3) a mix of fluxes + boron
that gives good melting and 4) don't overload with colorants. You are
easily meeting these four things with the glazes you showed us.
I would add that some of our most durable glazes are outside traditional
limits--you can see that in both high calcium semimattes--you have to go
outside traditional limits to get DURABLE mattes. The ones made within
traditional limits are usually not very durable because they don't get
thoroughly melted during firing.
Regards,
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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