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  • Arthur Petch

Firing two different glazes in one batch of pots

Question:

“ I have some Amaco celadon glazes that fire best at cone 5 so the colour doesn’t burn out, and a couple of pieces that have Amaco ancient copper on them (I have a note on each of those 2 pieces), which like a cone 6 with fast cool. I’m very much still learning, but I guess the best thing would be cone 5, with the 2 ancient copper pieces in the hottest part of the kiln (top shelf?) . Does that make sense?”


Answer:

Not really. The kiln has three thermocouples and three bands of heat elements and the whole point of that and the computerized controller is to keep the kiln at even temperature throughout.

Also, the kiln has a venting system that draws air from the top and out the bottom in order to remove fumes from the glazes to improve colour and toxic air. This also helps keeps the kiln at an even temperature because it draws air from the top of the kiln where normally heat accumulates in a closed space since hot air rises.

If you really want to give the pots the proper cone 5 and cone 6 firing I suggest you take advantage of the fact that I have small (1.75 cu ft) kilns as well as larger kilns (7.0 cu ft) and is, in fact why I have the two sizes.

The solution therefore is to put those pots you want fired to cone 5 in the larger kiln and the pots you want fired to cone 6 in the smaller kiln. Both have the venting but the smaller kiln, being smaller will cool faster and this happens to be exactly what you are asking for.

This solution will, not surprisingly cost more since we are firing two kilns and using up the lifespan of the elements of both kilns as well as using up more electricity and loading time.



 

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