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glaze test for red purple chrome glaze, cone 6, oxidation.

updated wed 8 jun 05


Alisa Clausen on tue 7 jun 05

Glaze tested on white midrange stoneware fired in electric oxidation to =
1220c. (2228f)

Source: Clay Times, March/April 2005
Credited to: Richard Burkett

Firing ramp:
100c p/h to 600c (212f - 1112f)
150c p/h to 1140c (302f - 2084f)=20
80c p/h to 1220c (176f - 2228f)
15 min. soak
cool down max. to 1100c (2012f)
Hold 1 hour
Shut off kiln

21 Gerstely Borate
16 Nepheline Syenite
11 EPK
20 Whiting
32 Flint

5 Tin Oxide
0.14 Chrome
.25 Cobalt Carb.

Note: All raw materials are measured up or down to the nearest half =
decimal. =20
Colorants or additives to a 100 gram test batch are measured in percent =
to the 100 gram test batch.

My color result must be due to that I could not accurately weigh 0.14 =
gr. My measurement was probally closest to 0.20, as I have to weigh a =
gram and divide it manually.

Gloss glaze, transparent, with a dark maroon, purple color. Where the =
glaze pooled in some crevices on the test tile, the glaze is blue and =

Regards from Alisa in Denmark