Kate Johnson on wed 16 feb 05
Further mochaware experiments to share, though I don't have the glazed tiles
shot yet...manana, perhaps.
Talking with Bonnie Staffel, Lili Krakowski and Trish Messenger about all
this, we'd been wondering about the possible effectiveness of various
additives to the mocha tea, which is basically water, acid, and an oxide or
other colorant. (I use tobacco for the necessary acid, some do well with
vinegar or other liquids.)
We did wonder if it might be profitable to add something else to the tea to
stabilize the branching effect of the mocha tea in wet slip, so I tried a
small amount of clay, as you would in a glaze, in one batch, a little gum in
another, and--as Lili had wondered about tobacco juice in spittoons--spit in
yet another.
Interestingly, the spit was the least successful, even in the initial bisque
firing. Very little branching, and ill-defined at that, to my surprise. (I
didn't let the mixture mellow, though, as might occur in a spittoon.)
Clay (I used my white earthenware slip) and gum (in this case a small amount
of gum arabic, as I didn't have CMC yet) both worked very well. The
branching was well-defined and crisp.
The effect is still softening under glaze, though--I believe the gum samples
retained their delicate branching best. (I used a very small percentage of
gum, but alas, I can't tell you exactly what it was. Less than 5%, I'd
say.)
I experimented with both cobalt oxide and manganese dioxide in the mocha
tea. The cobalt is by FAR the more satisfactory. It branches better,
retains its form better, and doesn't resist the glaze--the manganese bleeds
through, making a matt surface where it is most concentrated.
So...that's all for now, folks! Will keep trying with the glaze...Trish had
had good luck with a dipping glaze, but I haven't tried that yet. Many
thanks for the continued interest and inspiration...
Regards,
Kate Johnson
Graphics/Fine Arts
http://www.cathyjohnson.info/
http://www.epsi.net/graphic/
http://www.ebsqart.com/Artists/cmd_1494_profile.htm
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