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need cone 6 clear glaze without calcium byrd

updated sat 19 jan 08


Fredrick Paget on fri 18 jan 08

>Fusion frit 367 has no calcium - Spectrum glazes in Toronto sells
>it retail. I've got some and will be using it in iron glaze tests
>shortly. But, it has too little alkali to use by itself, so you
>have to find a calcia-free source of them to get sufficient flux.
>Nepheline syenite has 14.4 alkali vs. 0.7 calcia, but too much
>alumina to suffice for a cone 6 glaze. The only ones I've found
>with sufficient alkali are water-soluble, so I'm going to have
>to rely on olive oil as the solvent. That will be no problem on
>horizontal test tiles, but I've no idea how it would work to
>stick glaze to normal pottery surfaces.
>A: frit,Fusion 367
>E: 7.8 Na2O
>E: 38.4 B2O3
>E: 53.8 SiO2

There are several options.
If you can get some Cabosil, which is a pure silica condensed fume
material you can use a very small percentage- 1 or 2 percent - of it
to thicken a non aquaeous glaze. It is used in boat building and if
you are near any boat suppliers you can get it from them in retail
quantities. It is sold in bulk in 10 pound paper bags that are twice
the size of a 100 pound bag of plaster. And there is always the
internet nowadays. It is a strange substance . In water it does not
well at all but in solvents and resins it imparts what is called a
"nonNewtonian viscosity characteristic" If it is sitting still it is
a gel in the right proportions and when you move it with a brush of
whatever the viscosity goes a way down for a moment and then goes up
as it is left still.
Another possibility is a drying oil instead of olive oil. Silk screen
oil sets up very quickly and drys when exposed to air. It is sold in
bulk by Bel decals and retails in pints at $25 by Rynne China

Twin Dragon Studio
Mill Valley, CA, USA