Ababi on wed 17 apr 02
I open here an old discussion:
in
http://www.howkins.com/tuquoise.html
There are beautiful turquoise serving dishes
It is written: This brilliant Crackle glaze is
applied...... and: The platters are microwave and dishwasher safe.
What else there to check? The leaching?
Our dining room lady ( it looks like a big restaurant if you never
visited or saw in a movie a kibbutz's dining room), She had bought some
serving dishes like that, crackled turquoise glaze of course, deep blue
in the bottom. Beautiful, but cracks down these limits we try to build.
Is it food safe? Can crackle glaze be food safe?
Can Sodium turquoise glaze be food safe?
Here is a similar glaze I developed lately as an exercise to see what
would make 20 Strontium carbonate in ^04.
Can this glaze be used for food surface?
STRONTIUM BASE FOR LOW FIRE (F-4)
,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,
Cone 04 1050 deg.C. -
,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,
STRONTIUM CARBONATE 22.00
FRIT F-4 44.00
ENGLISH KAOLIN CC31 11.00
SILICA 22.00
copper oxide 3.00
,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,
Seger Weight%
KNO 0.385 10.00%
CaO 0.148 2.92%
MgO 0.002 0.02%
SrO 0.465 16.95%
Al2O3 0.243 8.71%
B2O3 0.296 7.25%
SiO2 2.562 54.14%
TiO2 0.000 0.01%
K2O 0.141 4.68%
Na2O 0.244 5.32%
Al:Si 10.54
Expan. 9.05
ST 338.46
It was one among 6 other tests, that has the less seen crackles.
Here is the recipe using the "half automatic" convection in Matrix
TURQUOISE SOFT BORAX FRIT (BATH)
,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,
Cone 04 1060 deg.C. -
,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,
SOFT BORAX FRIT (BATH) 21.20
Custer feldspar 45.40
EPK Kaolin 1.10
Dolomite 0.10
Calcium Carbonate 2.70
STRONTIUM CARBONATE 22.00
SILICA 7.50
copper oxide 3.00
,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,
Seger Weight%
KNO 0.385 10.13%
CaO 0.149 2.93%
MgO 0.001 0.02%
SrO 0.465 16.91%
Al2O3 0.243 8.70%
B2O3 0.296 7.25%
SiO2 2.561 54.07%
K2O 0.153 5.07%
Na2O 0.232 5.06%
Al:Si 10.54
Expan. 9.05
ST 338.40
,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,
I prefer the slow conversion but When I cannot find the materials, it
is a big and fast help. You must rebuild it to have more kaolin in it.
So back to the beginning
Can Such a glaze be foodsafe?
Does it matter anything about microwave or dishwasher when it is
crackled anyway?
Ababi Sharon
Kibbutz Shoval- Israel
Glaze addict
ababisha@shoval.org.il
http://members4.clubphoto.com/ababi306910/
http://www.milkywayceramics.com/cgallery/asharon.htm
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