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underglazes on bisque

updated thu 31 oct 96


Sharon Miranda on wed 2 oct 96

I recently found out that I prefer painting underglazes on bisque(white
earthenware). They move around more and create more of a water color look.
Of course the problem is that they might smear when brushing on glaze. I
know that I can spray on a cmc solution as a fixative, I'm wondering if I
can also spray on commercial spray starch. Does anyone have any experience
with this? (Eleanora?)
Of course I could also refire the pieces and of course I don't
want to do that. Thanks for any wisdom!
Oberlin, Ohio

RALPH on fri 4 oct 96

Fay, my better 3/4, says that you should use a slip that has CMC already mixed
in it. If you want even more of a water colour look, mix in some glycerine as
well. I make a slip base that has 25% each of Kaolin, Silica, Potash Feldspar
and Ball Clay. I cannot give you brand names as we are in South Africa. In John
Chappels book he adds a teaspoon of CMC to just about all his recipes. This is
about 5% of solution. The solution is CMC dissolved in water to make a saturated
solution. Kind

Eleanora Eden on fri 4 oct 96

Hi Sharon and All,

Are these underglazes smearing for you or is this a theoretical question?
My experience with commercial underglazes (I use Duncan and Reward) is
that they are formulated with enough gum to make smearing not only
improbable but nearly impossible. I'd try to smear the underglazes in
question before I'd worry.

Now if you're mixing Mason Stains that's another animal entirely and I
have not found anything that works well to make it stay put that won't
mess up the glazing except a film of sprayed-on glaze which is an
enormous hassle but works real well.

Since you aren't going to fire again before the glaze adding a bit of
your glaze to the underglaze would solve any smearing problems (as the
commercial glaze also has lots of gum) and also will solve another
problem which is the lowfire glaze crawling in places where the
underglaze is too potent and the glaze can't handle it. A very small
amount of glaze added, like just afew % worth is a good suggestion,
especially if you are having any of these tiny crawls.

Hope this helps,


Eleanora Eden 802 869-2003
Paradise Hill
Bellows Falls, VT 05101