Well, peeps… Here’s my first major project of the semester, in the kiln and ready to fire. These particular pieces are for the show we’re having in NYC at the Thomas Hunter Projects in a couple of weeks. If you’d like to come to the (closing) reception, it’ll be from 6-7:30pm on Friday the 24th of February. It would be nice to see you there! The show itself opens on the 13th. I believe it’s open to the public free, on weekdays.
This load will be fired to Orton cone 11. What does that mean, you ask? Cones are little tall skinny pyramids that melt at different points in the firing. Notice them in the upper right and lower left of the photo above. You can think of them as temperature gauges, even though that’s technically not correct – they measure the heat work done inside the kiln, not the temperature. For example, cone 11 will melt somewhere between 2359 and 2394*F, depending on how fast the kiln is fired. If the kiln is fired really slowly, the cone will melt at a lower temp than if it’s fired quickly, because there’s more heat work done in the slower firing. [Please see comments below for more explanation of heat work.]
So, to cut to the chase: you place cones in specific areas of the kiln, typically where you can see them throughout the firing. This kiln has two peepholes (or spies) in the front door. When the kiln is going, I can take out a peep (little refractory -non-melting- plug) and look in the hole to see my cones. As they melt or “fall” I can tell what’s happening inside the kiln. I can see if it’s firing evenly, from top to bottom, and adjust it accordingly. I can also tell when to start the reduction process (starving the kiln of oxygen to produce certain color response from the clay) and when to lighten the reduction. [To read more about reduction, see the comment section of this post.] The cones also tell me when my firing is finished. When cone 11 falls in this kiln (it’ll look like it’s bending in half and touching its toes), I know to shut the kiln off.
These pieces are paper-thin porcelain, so they should be super duper translucent after they’re fired (and changed from ‘clay’ into ‘ceramic’). I’m a little worried about the kiln itself though, because the last person who fired it had some problems with it randomly shutting off when it got to the higher temperatures. So, I might end up babysitting it on a nearby chair with a book for several hours tomorrow. Good times! Hopefully it won’t come to that, though. Wish me luck!