terracotta tests

Venky Anna at Doora, gave me three packets of clay to try firing in my ConeArt electric kiln. The bag of terracotta from Guhagar was also tested.

From Doora,

DIRECT CLAY - wild clay collected and sieved, and then left to age for a year. The clay is smooth and elastic - excellent for throwing. SHRINKAGE - 12.5%

SAND CLAY - Two kinds of sand mixed clays, ideal for coiling/hand building. SHRINKAGE - 15%

These were fired to 980 degrees in the Bisque fast firing setting on the kiln, with no hold, and one hour preheat. The warping was primarily because the clay wasn't dry, but the colour of the clay shows it can take the temperature.

the two clays - guhagar and direct clay - were tested with the terracotta glazes available with STUDIO CERAMIQUE, Calcutta to check glaze fit.

41 201 white glaze and 41 402 raku effect glaze were the most interesting results. To these, copper carbonate and cobalt silica blue stain 5202 has been added to check colour.

The results are definitely exciting, but more tests are important for better understanding of low-fire glazing.