Wednesday, September 29, 2010

Raku Firing

On Monday we tried a raku firing. The sun finally came out, after a week or two of wintry weather (very strange for late September!) and we took advantage of it. I decided to make miniature bottles as test-pieces for 6 test glazes and threw, glazed and fired a load of work in the same day, which was a lot of fun.

12 test pieces before firing
'Raku' means 'pleasure'. It is the Japanese art of quick-firing pots (usually tea-bowls) at a low temperature and taking them out of the kiln with tongs while still red-hot. They are then buried in sawdust to finish off the reduction, and dunked in cold water. The process is fast, risky, and exciting, both to watch and take part in. Usually one person opens and closes the kiln and sawdust bin, while the other person handles the tongs. Glazes on raku ware are often irridescent and brightly-coloured  in a way that you can't always get at higher temperatures. Because of the heat shock there is often a high breakage rate. Results are random and unexpected - but that just makes it more addictive - you get instant results, and you never know what you might get.

The four best pieces, after firing
This one is my favourite - I like the crackle effect around the rim.

Cat-to-pot ratio... to give an idea of the scale...

Sunday, September 19, 2010

Kiln opening

Here are the results from the gas reduction firing we did on Thursday. The pieces were glazed in two classic Chinese reduction glazes - Celadon and Copper Red. They were fired to 1300 degrees C (Cone 10).  A 'reduction' means that the oxygen is shut off to the kiln, creating a smoky atmosphere, starving the glaze components of oxygen.

The iron that gave the celadon glaze a pink appearance before firing (see the last post) is transformed to a beautiful pale green, and the copper- which would turn bright green in an oxidised firing - is a deep red, hence the name: Copper Red.

Here's a short video we made showing the kiln just after opening the door - you can hear the celadon making little 'ting' sounds as the glaze cools down and cracks. Days later, the pieces are still going 'ting!' from time to time as the glaze continues to develop its crackle effect.

And a You Tube video showing the traditional techniques of Longquan celadon in China:

Thursday, September 16, 2010


Spring has arrived here in Brighton. We spent the afternoon yesterday glazing a load of bisqued stoneware out in the sunshine:

Bisqued ware waiting to be glazed.

Pouring glaze into the inside of a bowl


Glazed forms, waiting to be stacked in the kiln.