Burnishing

PB-601Many ancient peoples used burnishing to make their pottery harder and more waterproof before they discovered the use of glazes.

Burnishing greenware pieces takes a lot of time and patience. I use a metallic, plastic or wooden object, or even better a polished stone such as an agata or hematite.

G-IMGP6159Hematite is a black iron oxide which gives a pinkish tone to certain white clays.

Burnishing is easiest when the clay is wet slightly with a lubricant such as vegetable oil.

When the piece has dried I fire it in my kiln at around 900 degrees (or at 980 degrees if it will be glazed inside later on – see below). When the piece has been fired I apply wax and polish it.

There is one very important point to keep in mind: burnished pottery should not be used for food or drink. However it is possible to apply glaze to the inside of e.g. a vase and fire it again (at 1,000 degrees) to make it waterproof.