A while back one of my fair readers had asked about what type of kiln I use for my pottery. I wish I could say I have a gas reduction or, better yet, a wood- burning kiln but alas, all I have right now is this electric kiln. I really hate that it uses so much electricity. Both for the carbon footprint and for my own pocketbook. For how much it fires at once, it is actually not too bad money wise if I keep new elements in it. But, I do endeavor to not use so much electricity and it is sort of a thorn in my side. I mean, it kinda makes me feel like a hypocrite in a way. I do a great deal to save power and certainly don't use much but still, I wish I had something else. On the other hand though, it burns very clean and is not a nasty process like the kilns that actually burn oil. You rarely see those but they do exists.
The shot above is of my last firing right as I had just opened the kiln. Most of the time, pottery is fired twice. The first firing is referred to as the 'bisque' and it is basically to drive out every bit of moisture from the clay and certain chemicals and contaminants also. The molecular structure of the clay is actually altered and it cannot be broken back down into workable clay anymore. Bisqueware looks like the flower pots you buy from the store and it is still porous, just like those pots.
The pieces are then glazed and fired the final time. The glaze firing is much hotter. In my case, I fire to about 2,230 degrees F ( I think: I could be off a few degrees), which is what we refer to as Cone 6. That is a mid-range clay. Porcelain and other stonewares fire much hotter. In this final firing, not only does the glaze mature, but the clay itself actually becomes vitreous (semi-liquid) and is no longer porous. There are hundreds of formulations of clay and these divided into categories where the clay bodies mature at certain temperatures. My clay would simply melt if fired to cone 10.
In the above photo I took a close up of the interior and of the cones I use to control the kiln. One small cone goes in a mechanical sitter so that when the desired temperature is reached that cone melts and allows and cut-off switch to drop, thus shutting the kiln off. Well, occasionally this doesn't work right; those sitters do sometimes malfunction so I always use a visual cone, or a witness cone as some call them. This is the large one you see sitting up by the plates. It normally sits in front of a peephole and I can physically look inside the kiln and see when it starts to drop. When I was in college we fired totally by sight in large gas kilns and so I am only comfortable doing it this way. Plus, it allows you to manipulate your firing if you want. Some glazes do better fired to a 'softer' cone 6 or whatever. You can tell by looking at how far the cone has bent as to the approximate temperature.
You can also see the plates are stacked in those neat plate setters. I love those things. Plates take up a lot of room in a kiln but those let you stack them vertically and they work great. By the way, the shelves and setters are made of a very dense clay-type material that will withstand temperatures much hotter than the pottery. They can warp though if you over fire. I found that out firsthand.
This is one place setting of some dinnerware that was recently ordered. I was very pleased with how it came out. It is very hard to get those red colors in an oxidation firing and that is what all electric kilns do. You can only do reduction firing was gas or wood. Why reds are hard to get in oxidation is a looong, boring explanation that involves a lot of chemistry so I'll skip that for now. I do actually understand it myself though! The specific kiln I use is a L&L. They are wonderfully reliable kilns and I like mine a lot. It is probably pushing 25 years old and still works great. You do have to replace the elements at least once a year, if not more, and this kiln has 6. It is not a cheap item of maintenance. However, old elements make the firings drag way long and that costs you even more. With new elements you can hit cone 6 in about 6 hours.
Now, amongst the clay elitists, cone 6 oxidation is basically sneered at. It doesn't have the 'mystique' and all of wood or gas reduction firing. In fact, when I was in college, we were not even taught how to glaze fire in an electric kiln. It was the unspoken, and sometimes spoken, idea that mid-range ceramics were inferior. That you could not get the range of proper expression with electric oxidation. However, I believe that a good artist can make good art out of whatever materials and techniques they happen to have available. Not everyone has the means or place for a large wood or gas kiln. But you know, those arrogant and narrow-minded views are often expressed by people that have the luxury of not actually having to make a living solely from their art. There is a tremendous amount of pretentious attitudes in the professional ceramic world that really makes me want to barf. I used to kind of hold those views myself way back when, because that is what I was taught, but after having been out in the real world and having to make a real living I see now that you do with what you have. Yes, I would like to have a wood-burning kiln. The surface expression you can achieve with them is amazing. And not all people who high-fire look down on us mid-rangers! lol! But for now, I will use what I have available and I will always have respect for my ol' L&L.