Carol Tripp on mon 24 mar 03
I’m back with more information. I went down the Art Centre and rooted
around the storeroom to find specific names and origins of the ingredients.
I got the analyses for them out of Mike Bailey’s Cone 6 glazes book. (Wish
I'd remembered this earlier.)
SiO2 TiO2 Al2O3 Fe2O3 CaO Mgo K2O
Potash
Feldspar 65.80 18.50 0.10 0.38 12.00
LOI 0.33, Na2O 2.89
HVAR 60.3 1.5 26.7 0.90 0.20 0.30 2.60
Ball Clay
LOI 7.10, Na2O 0.40
Potclays 1.88 0.173 0.634 0.003 0.033
Borax Frit
P2263 Na2O 0.330, B2O3 is 0.630 ,Mol Wt is 233.800
Remember, I used the Borax Frit instead of the following Calcium Borate Frit
as was called for in the original recipe.
Calcium 0.609 0.097 1.00
Borate Frit
Potclays B2O3 is 1.500 and Mot Wt is 207.100
P2268
To recap the recipe used: ^9-10 ox
22 Potash Feldspar
17 Flint
3 Dolomite
36 Borax Frit – THIS WAS THE SUBSTITUTE INGREDIENT used instead of the usual
Calcium Borate Frit written in the Glaze Record Book
22 HVAR Ball Clay
6% Tin Oxide (Potclays)
2% Copper Carbonate (Potclays)
The woman who has made this glaze many times before at the Art Center (sans
the copper carbonate) is sure she used the Borax Frit the last time she made
it. Perhaps Lili is right; the copper carbonate is to blame for the
resulting glaze that looks like at mint green version of a bumpy Oil Spot.
But I still wonder...
The above was a bear to type. I sure hope it comes out ungarbled.
Any help is much appreciated but I wouldn't wonder if this glaze is destined
for the dumpster.
Best regards,
Carol
Dubai, UAE where things are quiet and hot.
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