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raku glaze dilemna

updated sat 2 nov 02


Carolyn Bronowski on fri 1 nov 02

Dear Clararters. Here is the Problem. At a workshop several weeks ago, I
asked Vince to critique one of my hand built pots. The top of the pot is
smooth, and the rest is covered in a heavy grog soft clay. The top is a
shinny black raku, and the rough is a matt rainbow. He remind me that the
glaze I was using would turn muddy in a few years. I have been working with
Ramom Camarillo" ^04 Rainbow glaze from the July/August 20000 CLAY TIMES. I
fire this glaze at a temp of about 1850 instead of cone 04 I use very
little paper/sawdust in post-reduction. The recipe: Gerstly Borate 40%,
Bone Ash 30%, Nepheline Synite 20% and Copper Carbonate 10%. I can fire
without a glaze on the top of the pot, get a nice black, and make it shinny
later. But, I don't know how to alter the Rainbow glaze. I found Marcia
Selsor's Alligator Raku glaze: G.B 74.42% altered to 50%, Bone Ash 18.60
altered to 25%, Copper Carbonate 4.65% altered to 12.5 %. The original
glaze had cobalt 2.33 % which she deleted and added Nephline synite 12.5%..
Has anyone had experience with the original or altered glaze? Then, in the
September 2001 CERAMICS MONTHLY I found the New Dry Alligator Glaze with
G.B. 57.14%, Bone ash 28.57%, Nephline Syenite 14.29%, Cobalt Carb 1.43%,
Copper carb 5.0% and Manganese dioxide 1.43% Anyone with experience with
this glaze? All ideas are so welcomed. Thanks Carolyn