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ketchup red ^5 glaze test results

updated tue 30 apr 96


Jeremy/Bonnie Hellman on tue 23 apr 96

I tried several of the cone 6 oxidation glazes but my kiln bent the ^6
witness cone only slightly. Ketchup red is wonderful--not Heinz ketchup
red, more like the ketchup red from the time we had an abundance of ripe
tomatoes and overcooked a batch of ketchup. However, it had a frosting of
tan and the plate and bowl are great looking. The glaze tended to flake off
when dry and required careful handling on non-grolleg ^6 porcelain
(Standard Ceramics # 213). Has satin finish. Not tested for durability or
baked beans-yet.

Flint (325) 30
Custer Feldspar 20
Talc 14
Gerstley Borate 32
(Yes I know these add to 101 not 100 but that was the recipe)
Add Red Iron Oxide 15

I only hope that the frosting remains at cone 6.

BTW my firing took 8 hours and the sitter had a cone 7 placed in the middle
of the sitter. Kiln was quite full. Don't know why I didn't get to cone 6
on any shelf. (Obviously I failed to check the witness cone when the kiln
shut off-my goof.) Any ideas from the group, please.

Bonnie in Pittsburgh, PA new to testing glazes but having benefitted
greatly from group discussions, thank you all