Alumina increment tests

20 x5

20 Kaolin, 20 Dolomite, 20 Silica, 20 Spodumene, 18 Frit 169.

 

Although the Si:Al ratio indicates that the glaze is losing gloss as the alumina increases (adding free kaolin), I do not see a definitive difference in the overall gloss of the individual tiles from the least to the most. But with the added rutile, the effect of decreased variegation and phase separation is visually apparent. As the alumina increases and stiffens the glaze, the reactive surface decreases until it is almost uniformly melted and glossy. The first tile #1 with the least alumina, has a fine variegated surface and opalescence.

The recipe 20g of each

EPK, Dolomite, Silica, Spodumene, Frit 169

#1 Added 1/4 more Kaolin (5g) and recalculated for a total of 24g.

#2 Added 1/3 more Kaolin (6.6g) and ...a total of 25g.

#3 Added 2/4 more Kaolin (10g) and ...a total of 27g.

#4 Added 2/3 more Kaolin (13.3g)and...a total of 29g.

#5 Added 3/4 more Kaolin (15g) and... a total of 30g.

 

Alisa Liskin Clausen

Done