Friday, October 9, 2020

Back to Basics, Back to Clay

Yesterday was a slog with a two hour meeting after the work day, and again a meeting today even though it's Friyay. I decided the kiln was full enough on Wednesday and let it fire. As my colleague, Zan was explaining the ramping up and cooling stages, I asked isn't this all in a textbook? And yep we were both thinking of John Toki's textbook, which she's letting me borrow.


And so I quote, a cone 05 bisque-firing program for pottery and sculpture 1/5 - 3/8 in. (7-10mm)shows that the entire firing requires 22 hours. In theory, the firing begins at zero degrees.
  • Segment 1: Preheating the ware takes 4 hours with the kiln lid propped up 3 inches and all the peepholes open. The kiln temperature is programmed to rise at a rate of 60 degrees Fahrenheit/16 degrees Celsius per hour until 250 degrees F/116 degrees C is reached.
  • Segment 2: The temperature rises at a rate of 100 degrees F/38 degrees C. The entire segment occurs over an 8-hour period in which the kiln temperature rises to 1040 degrees F/561 degrees C.
  • Segment 3: The temperature rises at a rate of 65 degrees F/18 degrees C per hour over a period of 4 hours until it reaches 1300 degrees F/704 degrees C.
  • Segment 4: Temperature rises 133 degrees F/56 degrees C per hour over a period of 3 hours until reaches 1700 degrees F/927 degrees C.
  • Segment 5: Temperature rise per hour is 72 degrees F/22 degrees C for a total of 3 hours until 1915 degrees F/1046 degrees C is reach at which point the kiln is turned off and left to cool.
Except we didn't lift the lid or open any of the peep holes. And Zan showed me ergonomic lifting of the kiln shelves and which were the clean ones to use as well as using the clean or side of the shelf which had no kiln wash or glaze drips as well as rotating the kiln posts and scraping against the shelf for smoothing if a shelf seems wobbly. And I believe we used 3 posts per half round. The next time I watch Zan program the kiln, I'll remember to bring my clay journal and to log the firings.

Like I mentioned, yesterday was a bit of a whirlwind at work, and I so longed to cook and not just reheat leftovers. I was also craving steak and a baked potato loaded with lots of butter, sour cream and green onion. And vegetables! And so I roasted brussel sprouts and heirloom colored carrots. And despite all that dinner and more leftover birthday cake I wanted a breakfast burrito this morning. 
But truly the reward to my fin de semana were all the bisque ware.
And so I'll be glazing probably Saturday and Sunday.
I recognize the sandstone (or maybe it's speckled buff) that I had left in the Central Park studio, but the salt crock and bonsai platter is a smooth red clay body.
I definitely want to throw some bowl bottoms on which to adhere slabs for soup vessels or make more greenware for another bisque firing soon as well as glaze my bisque pots. Oh the surface possibilities!

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