Rick Sherman on wed 30 sep 98
Returned from a trip and discovered the interesting discussion of
rutile blue as well as some formulas for black. Also, Laurie requested
the receipt for Toshiko Black. Here is that formula as well as an old
rutile blue called Woo Blue
Toshiko Black: Semi Matt fires in Oxidation and Reduction
Works at cone 10 but I have taken it to a hard 11.
Potash Feldspar [G200 or Custer] 40
Cornwall Stone 20
EPK 20
Whiting 20
Zinc Oxide 7
Bentonite 2
Total 109
Add:
Red Iron 15% 16.35
Cobalt Carb 3% 3.27
Manganese Carb 1% 1.09
OR
Manganese Dioxide 1.38% 1.50
Best used fresh. If it sits for a week or more it becomes thick and has
to be thinned with H2O but may check during drying on the pot. Then can
crawl on fine stoneware or procelain in firing.
Woo Blue: Cone 10 to 11 in Reduction. Smooth and glossy deep blue
where thick with brown flecks or, if brushed with red iron, gives a
strong, rich, dramatic brown.
Spar [G200 or Custer] 42
Kentucky Ball Clay 13
Whiting 18
Flint 27
Total 100
Add:
Red Iron 4% 4
Rutile 4% 4
Bentonite 1% 1
Try them.
Rick Sherman
San Jose, CA USofA
sherman@ricochet.net
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