Friday, 4 November 2011
On discovering that my 'orange' was firing to an unpleasant brown colour I threw the whole tub of ochre away thinking I would never be tempted to use it again.
I then went on to glaze more pots, wondering what I would do with them if they were all spoilt. It was only when I unpacked the second glaze firing that I remembered that I had used a different batch of glaze in the first firing. Confused?
I had mixed ( or more precisely my 18 year old) had mixed a glaze for me using lead bisilicate rather than my usual lead sesquisilicate. The reason being that 1. I had plenty of lead bisilicate 2. My supplier pointed out that bisilicate was cheaper than sesquisilicate.
So the pots with the brown were with the new glaze! I have since done another glaze firing with my original glaze and no problems!
I can hardly believe that the difference in colour can be caused by using a different frit but that does seem to be the case.
It does mean that instead of possibly loosing eight weeks of work I have only 'lost' five pieces. Also that I probably threw away a perfectly good batch of 'orange'.
The pictures are of work out of the kiln today. Orange miraculously returned! The top bowl is a Christening bowl which is a commission and I am pleased with the way it has turned out so I hope my client also likes it.
I am now compiling a list of things to remember!
1 Test everything.
2 Never use grogged clay ( that is another story)
3 ..... to be continued