search  current discussion  categories  glazes - cone 4-7 

glaze test for frogpond green mat, cone 6, ox.

updated mon 11 feb 02


Alisa og Claus Clausen on sun 10 feb 02

Glaze test for: Frogpond Green Mat, 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)


31 Frit 3124
31.7 EPK
23.2 Wollastonite
14.1 Flint

5.5 Dark Rutile
plus increasing amounts of copper carbonate, see below:
All raw materials measured up or down to nearest whole decimal.
Oxides used on percent basis to a 100 gram batch of glaze.


Resulted in:
0.5 Copper Carb.
Light green smooth gloss with slightly pearly texture showing underneath
the gloss. Glaze moved, and pooled around boarder where glaze was dipped up
to on test tile.

1.0 Copper Carb.
Same as above, but slightly greener. The glaze has larger streaks and
shows pearly edges outlining the streaks.
Also pooled around glaze edge on tile.

2.0 Copper Carb.
Same as above.

5.0 Copper Carb.
Dark green gloss. From fine streaks can see glaze moved straight down tile
and dripped off tile.

I did not get a mat, but that must have to do with firing ramps.
Can try again with up to 3.0% Copper carb. after I read John and Ron's book.

Regards from Alisa in Denmark