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subject: re: but i still don't get it! (egyptian blu

updated tue 25 jul 06

 

Ivor and Olive Lewis on sun 23 jul 06


Thanks to Dave, Ron and Liisa Reid for doing the calcs for me. I =
appreciate the effort.
One thing continues to worry me about this example, The Chemistry.
It is given as being a possible Cone 04 glaze, (1060 deg C.)
The only ingredient that will be molten at this temperature will be the =
Soda Ash. So the other ingredients have to dissolve in that to create a =
vitreous glaze. No doubt that will happen to some degree. But will =
highly refractory Calcium oxide dissolve ? What is the rate of solution =
of G Spar in molten Sodium carbonate? Silica will react with molten Soda =
Ash releasing Carbon dioxide to generate water soluble Sodium =
Disilicate. Will this take those other ingredients into solution? The =
fate of Copper oxide is also a problem since it is not known for its =
ability to react chemically with Silica to form Copper silicate. =
Information I posted recently suggests that it will not even melt.
The potential Chemistry suggest to me that this is not a good recipe.
Best regards,
Ivor.