[Clayart] Thanks to Ron Roy for helping me reformulate a glaze

[Dragonbelly Ceramics]

I posted a few months back about a glaze that I have long used with weird
chemistry. Ron was gracious enough to look at it and remind me that not all
stable glazes exist within a narrow band of chemistry and he gave me an
alternative formula that (bonus!) used less spodumene and matched the
original with a slightly higher COE (the origonal was quite low).

I am pleased to say testing it showed me a glaze that completely matches
the original.

It also passed a 24 hour lemon test.

This is the original formula:

Tom West Green, Cone 6

Ferro Frit 3269: 27
Gerstley Borate: 15
Spodumene: 40
EPK: 18
Copper Carbonate: 5
Tin Oxide: 7

COE: 6.1  R20:RO 0.72:0.28 Boron: 0.45

Ron Roy's adjustment:

3269 .............. 27.0
Gerstley Borate .... 15.0
Spodumene ......... 28.0
Neph Sy ........... 12.0
EPK ............... 18.0
Total .............100.0
+ copper carbonate 5
+ Tin oxide 7

COE: 6.6 R20:RO 0.71:0.29 Boron: 0.46

It's a glaze that on iron rich clay when thin is a lovely orange. When
thick a shimmery metallic green.

On white clay, thin is a mossy green, thick makes a metallic green that
breaks black.

It also appears to withstand years of exposure to the dishwasher without
any breakdown in color.

And no one know where the glaze came from. It was in use at a former studio
I belonged to outside of Boston without any attribution or known history.

Best,
Lisa
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