Friday, February 10, 2012

Mostly Waterproof

Kiln sheds have to be fireproof. Anything that will withstand fire will also withstand water fairly well. Except electronics. 
My pyrometer (temperature sensor) was sitting on a besser block 25 cms above floor level- therefore 15-25 cms below floodline. Dead as a doornail, and with other things on my mind I didn't manage to chase one up from a Melbourne supplier before a looming deadline. But I've been keeping a kiln log, and hooray, I'd put it safely up high! As well as records of time elapsed, gas pressure, air intake, flue adjustments, I'd also made observations of kiln behaviour such as colour changes observed through the spyhole. So I fired without the pyrometer.
I made up four test rings of an earthenware clay and lined them up behind the spyhole. Checked my firing log for a good bisque firing, matched adjustments to the previous records and also compared observations (and took plenty of new ones). According to my notes as the kiln reached the right heat the interior colour moved from cherry red to scarlet, reaching fluoro orange at 1050 deg.C. So at fluoro orange I pulled out a test ring. Lovely colour and a nice vitrified ring when I tapped it. Kiln off, success! 
I won't pretend I wasn't nervous. But a bisque firing has a wide tolerance range for finishing temperature, anything between 900-1100 degrees would do. Even still I was edgy until I'd pulled out the lovely little test ring. :)

No comments:

Post a Comment