Monday, September 13, 2010

Driveway firing

Finally got a two day sunny forecast so I could do the maiden firing of this little Olympic, gas test kiln. I'm bisquing it to season the ITC100 coating. It's firing empty other than two  shelves and a few pieces of  ITC 100 coated kiln posts.

It took off really fast even on what I thought was the lowest setting, so it looks like it may be done by dinner time at this rate as long as there are no wind gusts to blow it out.  Right now it's over 800F. My makeshift metal and kiln shelves surround seems to be doing alright under these no wind conditions.

Think I'll change the days studio plan and make up some glaze tests so I can do a soda firing in it tomorrow or the next day if weather permits, with some re-fires and glaze and slip tests. I've designed a couple of alkaline base glazes in the hopes I can get those lovely alkaline copper colors without crazing. Problem is when you add enough silica to lower expansion, that acidic nature of the silica changes the alkaline quality and you lose the colors; And even with enough silica, sometimes the alkaline content is too high and you still get some crazing  Therefore,  I keep testing. I probably should do some of Ian Currie's grid testing one of these day if I could only find more hours in the day.


  1. What is the ITC coating used for? Is that the same as kiln wash? or is that because you intend to use it for soda firing? Looks bigger than a test kiln to me. I'd love to have a gas kiln; one of these days. Good luck with the firing.

  2. Linda, it's only 4 cu feet, which isn't much at all. It's sitting high on a cart which makes it look larger. You can build yourself a little updraft kiln by just dry stacking some insulating firebricks and using a good weed burning torch with a 50,000 BTU rating and a 7 gallon propane tank. Your local propane supplier can make the fittings with a manifold that you can use to have both kilns hooked up so if one empties, you can switch right over to the other, as well as a gauge to monitor the pressure which you can get at most big pottery supply companies. I just happened to get a really good buy on this little kiln, otherwise I would have just made my own.

  3. PS ITC 100 protects insulating firebricks from the corrosive quality of soda and salt. Some say it actually helps the insulating quality of the kiln. It's a zircon mixture with I think additions of clay and sodium silicate.

  4. Thanks June, and thanks for the info on the gas kiln, I am going to save these instructions and when I have time build myself one. I just love reduction. and I just unpacked all my previous work this week and it had me dreaming about it again. I better stick with cone 6 for now though, don't want to spread myself too thin.