sharon on sat 12 aug 00
Dear folks:
Here is the Hersch glaze I was looking for a while back. It's from Sandi =
Pierantozzi and in a conversation she told me it was NOT food safe. I =
did an acid test, following her suggestion, w/ a lemon slice and indeed, =
it leached out.
There are 2 things I 'd like to know:
Can this (beautiful silky satin easy to use and love) glaze be made food =
safe?
And: I've tried to add 2% cobalt carb and (separately) 8% yellow iron =
oxide to make 2 new colors. The colors are what I want - a lovely dark =
blue, and a mottled tan, but the sheen is gone. It seems to need more =
flux.Comes out too matt and stiff. Probably the copper carb (to make the =
green) provides some flux? Could anyone advise about how to get a dark =
blue and a yellow/tan with this glaze, keeping it's satin, semi-gloss =
texture?
Hersch glaze cone 04 electric (for terracotta)
GBorate 31.54
Lithium Carb. 8.7
N.Synite 8.7
EPK 4.15
Flint 34.86
Whiting 16.6
emerald green: copper carb 7 - 8 %
thank you in advance.
Sharon Miranda
Sharon.Miranda@Oberlin.edu
Ron Roy on sun 13 aug 00
Hi Sharon,
No way you can keep that much copper in a glaze - the debate is - will it
leach enough copper and lithium to be toxic. I can say I am sure it will
change colour with some foods quickly. Best not to put it where it can come
in contact with any food says I.
RR
>Here is the Hersch glaze I was looking for a while back. It's from Sandi
>Pierantozzi and in a conversation she told me it was NOT food safe. I did
>an acid test, following her suggestion, w/ a lemon slice and indeed, it
>leached out.
>
>There are 2 things I 'd like to know:
>
>Can this (beautiful silky satin easy to use and love) glaze be made food safe?
>
>And: I've tried to add 2% cobalt carb and (separately) 8% yellow iron
>oxide to make 2 new colors. The colors are what I want - a lovely dark
>blue, and a mottled tan, but the sheen is gone. It seems to need more
>flux.Comes out too matt and stiff. Probably the copper carb (to make the
>green) provides some flux? Could anyone advise about how to get a dark
>blue and a yellow/tan with this glaze, keeping it's satin, semi-gloss
>texture?
>
>Hersch glaze cone 04 electric (for terracotta)
>
>GBorate 31.54
>Lithium Carb. 8.7
>N.Synite 8.7
>EPK 4.15
>Flint 34.86
>Whiting 16.6
>
>emerald green: copper carb 7 - 8 %
Ron Roy
93 Pegasus Trail
Scarborough
Ontario, Canada
M1G 3N8
Evenings 416-439-2621
Fax 416-438-7849
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