Interview with South African ceramic artist John Shirley - Ceramic Technique - Soluble Salts, April 2011
John Shirley: I currently work in a bone china body which I produce from locally available materials. I have always been drawn to translucent bodies and the one I am currently making is more translucent than any I have used previously. Being bone china it is also whiter then any body I have previously used as the bone ash in the body acts as a bleach on any traces of iron in the body. The work is cast in moulds which I make using Paperplaster. This method uses less plaster than conventional mould making methods and results in much lighter moulds which are far easier to handle. The pieces are bisque fired to 1080oC and then sanded to achieve an extremely smooth surface which I decorate with wax resist and solutions of various soluble salts before the final firing to 1250oC in an electric kiln.
Ceramics Now Magazine: What is the starting point in your investigation (research) with soluble salts?
I have always been intrigued with soluble salts ever since first seeing the work of Arne Åse. A local ceramic supplier had some cobalt chloride that had been on the shelves for some time and presented it to me. So began the tests with solubles and I am hooked to this day. I have tested a number of the salts in different solutions and in different layers. For some effects I fire between layers to achieve specific effects. Some of the salts are not available locally, and I work mainly with different strengths of Cobalt, Ferric and Nickel Chloride and Potassium Dichromate solutions.
Salts of Cobalt and chrome on bone china - View his works
What did you learn from working with different materials?
I am fascinated by the chemical aspect of the ceramic process, and much of my work has been informed by this. I have previously worked extensively with crystalline glazes and creating reduction effects in electric firings. I think technical challenges are what keep me going and there is always something to investigate. I find that for me it is essential to focus on one thing at a time and at present I am occupied with the effects of layering the salt solutions.