Glazing and firing a porcelain bowl

The 2nd of the bowl videos.

The bowl is biscuit fired to around 1000 centigrade.

First a blue celadon glaze is applied to the inside of the bowl and within the footring. The thickness of this glaze layer is critical. Once it has dried, usually a day in the summer, a layer of way emulsion is painted over the surface.

Once this has dried, usually another day, the excess glaze is washed away. When the bowl has dried again it is dipped into a tenmoku glaze. This has 10% iron oxide in it, hence the colour.

Again excess glaze is removed from the bowl. The bowl is fired in a propane kiln to around 1280 centigrade. The top 280 degrees are fired in reduction, where the oxygen levels inside the kiln are limited.

This gives an extra whiteness to the porcelain and changes the colours of the glazes. the blue celadon would otherwise be a pale yellow.

The firing takes about 12 hours, with 3 hours taken over the last 100 degrees. The kiln takes 2 days to cool down so that it can be unpacked.