iandol on mon 30 sep 02
Dear Gavin,
You say <"fluxes" come about because of contact melting of eutectic combinations =
in the powder phase. Put two slightly refractory powders in close =
contact and heat to below their individual melting points, but above =
their combined eutectic,>>
I tried this with three such powders, Silica, Whiting and Aluminium =
Hydrate with the intention of getting the 1170=B0C Eutectic. Weighed out =
the correct proportions of each. Got a sample up to Cone 9 with my kiln. =
Still raw powder. Did not even sinter though I was well into the Tamman =
temperature range for Silica and Alumina and pretty close to it for =
Calcia.
No, To get the eutectic melting shown on the Phase Equilibrium Diagrams =
you need the Mineral Species given in the Phase Fields. If you do that =
then I can guarantee you will get a successful melt from an intimate =
mixture of the correct proportions, though you may need give it a bit =
more heat to be sure.
By the way, once some sort of melting has happened it is not possible, =
by definition, for further Eutectic intervention. Think "Solvation" as =
being the best way of describing what is happening as clay and glaze =
mature. Boric Oxide is a fantastic "Solvent". That is why so many =
recipes include it.
I think you have the right idea, about doing the experimental work. =
Would love to take part in that if there were a nearby Lab.
Best regards,
Ivor Lewis.=20
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