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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.

Source: www.frogpondpottery.com
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)

Recipe:
50 Gerstley Borate
15 EPK Kaolin
35 Slica

ADD
1.5 Cobalt Carbonate
3.0 Copper Carb.
1.0 Dark Rutile

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

Substitutions:
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