search  current discussion  categories  glazes - cone 4-7 

glaze test for stonehenge, cone 6, ox.

updated mon 11 feb 02


Alisa og Claus Clausen on sun 10 feb 02

Glaze test for: Stonehenge, cone 6, 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)

5.6 Flint
18.8 Whiting
51.6 Soda Feldspar
15.4 EPK
8.6 Zinc ox.

1 Cobalt Carbonate
4 Rutile
3 Granular Ilmenite
add after screening

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

1 gm. RIO for 3 gm.RIO for grounded Ilmenite.
Because Hamer and Hamer describes Ilmenite as Iron and Titanium Oxide, and
because Rutile is describes as natural Titanium oxide with up to 15% iron
oxide) The recipe calls for Rutile already.

Resulted in:
A streaking and moving blue gloss. Where thinnest, the glaze is a dark
cobalt blue gloss. Where thickest, the glaze turns more to lighter, whitish
blue, with streaks and feathers. I would like to hear what the original
recipe result looks like. I did not expect such a blue glaze. Even though
the glaze moves a lot, it stayed exactly where glazed.

Regards from Alisa in Denmark