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glaze test for black semi metallic, cone 6 ox.

updated mon 23 aug 04

 

Alisa Clausen on sun 22 aug 04


Glaze test for Black Semi Metallic, Cone 6 ox.

Glaze tested on white midrange stoneware fired in electric oxidation to =
1220c.

Source:
Credited to: Alisa Clausen glaze experiment

Firing ramp:
100c p/h to 600c (212f - 1112f)
150c p/h to 1100c (330f - 2012f)=20
100c p/h to 1220c (212f - 2228f)
5 min. soak
cool down max. to 800c
Hold 1 hour
Shut off kiln

Recipe:
65 Red Clay (Oldenwalder clay)
20 Borax
10 Dolomite
5 Silica

ADD
2 Cobalt Carb.


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

Results:
Covering, semi metallic glaze. Glaze is black overall even where =
thinnest and did not break brown on the tile.
The surface is well melted and there are small crystals where the glaze =
is thickest, typical of oversaturated iron.
Smooth surface.

Regards from Alisa in Denmark