|Monthly Tech-Tip |
These are two cone 6 transparent-glazed porcelain mugs. On the left is the porcelainous Plainsman M370 (Laguna B-Mix 6 would have similar opacity), it is semi-vitreous and has no translucency. Right is a highly vitreous, New Zealand kaolin based porcelain, Polar Ice. The secret to making this porcelain super-white is the NZ kaolin. The secret of its impossibly-high plasticity is the very expensive plasticizer, VeeGum T. What about the translucency? Nepheline syenite is used as the feldspar, but it alone cannot deliver this kind of translucency at cone 6. Amazingly the 4% Veegum acts as a translucency catalyst, it is the secret. Commercial manufacturers could never use a sticky and difficult-to-dry porcelain like this, but a potter can do incredible things with it (e.g. throw thinner, lighter, bigger than any other clay he/she has ever used!).
New Zealand Halloysite
The whitest burning kaolin we have ever seen. It is very sticky when wet, suspends glazes well & makes super white porcelain (with help from a white bentonite).
Formulating a Porcelain
The principles behind formulating a porcelain are quite simple. You just need to know the purpose of each material, a starting recipe and a testing regimen.
A ceramic whose priorities are translucency, whiteness, fired strength and resistance to thermal shock failure.
A 3-minute Mug with Plainsman Polar Ice
Tony Hansen takes you through the steps from opening the box and wedging the clay to taking the fired mug from the kiln.
Plainsman Polar Ice cone 6 translucent porcelain