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glaze test for broken or mottled blue, cone 6, ox.

updated mon 11 feb 02


Alisa og Claus Clausen on sun 10 feb 02

Glaze test for: Broken or Mottled Blue, cone a6, ox.

Credited to:

All tests fired on white, iron flecked, mid-range stoneware.
Fired to cone 6 (1220c) in oxidation.

Firing ramp:
100c (212f) per hour to 600c (1112f)
150c (302f) per hour to 1100c (2012f)
100c per hour to 1220c (2228f)
15 - 30 minute soak depending on matts and glosses used.
cool down 100c per hour to 900c.
Natural cool down to 150c (approximately 15 hours)

50 Gerstley Borate
15 EPK Kaolin
35 Slica

1.5 Cobalt Carbonate
3.0 Copper Carb.
1.0 Dark Rutile

All raw materials measured up or down to nearest whole decimal.
Oxides used on percent basis to a 100 gram batch of glaze.

Common Rutile for Dark Rutile

Resulted in:
A well covering medium to dark blue gloss glaze. Has a very nice fuzzy or
hazy texture under the surface of the gloss. Where thicker, it fuzzes up
more under the surface to give entire areas of breaking lighter blues.
A lot of changing nuances over the entire surface. Stayed where glazed.

Regards from Alisa in Denmark