|Monthly Tech-Tip |
These mugs were fired in the same kiln load at cone 10R and have the same clear glaze, G1947U. The mug on the left is a Grolleg kaolin (52% Grolleg kaolin, 24% silica and 19% Mahavir feldspar, 5% bentonite). The one on the right is 15% M23 ball clay, 40% #6 Tile kaolin, 15% Nepheline, 25% silica, 3% bentonite. Clearly, the Grolleg porcelain fires so much whiter.
A clay deposit that is near the site of erosion and alteration. They have more mechanical impurities and fewer chemical and mineralogical impurities. Primary clays have larger particles and less plasticity.
How do you make porcelain? There is a surprisingly simple logic to formulating them and to adjusting their working, drying, glazing and firing properties for different purposes.
Tile #6 Kaolin
A white burning kaolin from the UK, commonly used in porcelain bodies and as a glaze suspender. Sticky when wet, low plasticity.