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barbara looking for black

updated fri 31 may 96


ff on mon 6 may 96 wrote:
> ----------------------------Original message----------------------------
> The subject really says it all.The glaze base seems to remain beyond my reach
> and I need to obtain a cone 5-6 matt black glaze for oxidation. Any help

Here is my black cone 6 ox formula. This glaze is more satin than matt,
however, additions of epk should give you what you want.
G200 Spar 26
Gerstley Borate 16
Silica 26
EPK 22
Dolomite 18

Cobalt Carb. 2.7
Black Iron Oxide 15

The expansion number for this glaze is very low, but I think there is
more chance of crazing than shivering. I don't know why but probably
the high iron content increases the co-e of expansion. To increase matt
2-4 more parts of epk will probably do. I have tests using this base
that look like old-fashion chalk boards.