Balnacra Arts by Vicky Stonebridge

Raku Firings

Did a couple of Raku Firings today. The first one was a success, and nothing broke. I was ably assisted by Andrew- I hope he wasn’t too seared by the smoke! I enjoy the eyes streaming lung choking process, but it is pretty nasty, so I don’t enjoy inflicting it on others. I am still off sick from my Fire service job with an injured elbow, If i was missing the Fire, smoke and smell this will fill the gap! It always bemused me that colleagues were unaware of how my skills were in any way relevant to Fire fighting, they never seemed to get that anything that an ‘arty’ woman knew  could compare to all those macho manly skills the rest of the crew had. I was often complimented on my ‘secretarial’ or people skills, when of course I actually have a degree in ceramics, which is all about the chemistry and physics of Fire and the effect of Fire in different spaces and on certain objects, a deep seated intuitive understanding of the sound, smell, colours & movement of fire- so often I wished i could pop some pots into a nice conflagration before we put it out… Oh and anyway, of course being a woman, i’m good at making coffee and tidying too.

Raku is a word for, i suppose what you’d call a smoke firing technique. The only kiln I have left, is one i’ve had since around 1990, it is designed as a raku kiln, it doesn’t do so well for normal firings, as it only has one burner so getting an even and controlled temperature is difficult. The trick is to pre cook the pots ( bisque firing ) , then glaze them up with very low temperature glazes, I like ones with a high oxide content as they give you nice metallic colours. I only make small pots because my clay is very old and tired and the kiln is pretty small, bigger items would split with the temperature variations in that little chamber.

Because the first firing worked and I had enough pots glazed ready to go I re-loaded the kiln up again while it was still hot.  The down side of this was that my able assistant had left, and that it soon got dark. My shed has no electricity supply & the only torch i have is my phone, so i lit the place up with candles, a very romantic valentines work shed!
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with a normal glaze firing, you get to the top temperature & cool it gently, not opening the lid until it is cold. However with Raku, you open it up when its is very hot and the glaze is in a molten glass stage, between 600 – 900 C, it quickly cools and hardens so you have to move fast. While the glaze is still hot, you must lift the pots out and put them into an oxygen depriving situation, usually in sawdust. The sawdust will smoke, smoulder of go ‘Ploof’ on fire, keep covering it up to suffocate the pot and create chemical changes which change colours and create that blackened metallic effect. Green becomes red and so on. We also call this a reduction as opposed to oxidisation.

Here is the kiln with the lid off, and the first layer of pots and the shelf removed, it is cooling down, hence the dark edges of the pots. The pots are lifted out with long metal tongs, welders gloves, and I am hatted & masked up. I do need to invest in better masks if i am going to go this more often though. A face full of that yellow sawdust smoke is nasty. Fire service Breathing apparatus would be perfect! Shame i can’t borrow the kit!
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the sawdust is in a metal bin, once this has smoked and burnt down a while the pots get lifted out and cooled in water, they still hiss & bubble at this stage. Often shattering.
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Here are some of the results from today. They will of course be put for sale in my web shop and various gallery outlets. Message me if you like the look of anything. Raku also makes a great workshop to run, as long as participants don’t mind smelling very like kippers at the end of the day!
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This entry was posted on February 16, 2014 by in Blog and tagged , , , , , , , .
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