Saturday, January 29, 2011

Ring Of Fire

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.


karl said...

I love johnny cash but I might prefer the wall of voodoo version best.

electricity can come from green sources.

HermitJim said...

Having made both ceramic and porcelain pieces from the molds to the firing, I'm familiar with how it all works. Makes it so much more enjoyable to be able to really appreciate the time and effort that goes into what you do!

Creating something by hand from start to finish...sure is satisfying!

Good for the heart, good for the soul!

Have a special day, my friend!

Anonymous said...

Well, yes you use what your have and purists be damned. If that is what you want to call them. If you have to chop down trees, to burn wood and then you have to weigh it all, balance, panels, etc.
Love your pottery. My sister bough some pieces that had horsetail hair in them from an artist from Ok. Makes for interesting pieces. Purchased those @ the Fairhope Arts and Crafts Festival in March. Great show. More arts than crafts.

JoJo said...

OMG ANNIE, They are awesome. just got home about an hour ago and jumped right in the shower. lol then sat here to check e-mails and see if you posted the dishes. Check will be in the mail today. Can't wait to get them here. I love the red pieces being a ceramist I know about the red. I love all the colors I saw.

Jenn said...

The function and beauty of the bowls we have from you speaks far more than any snooty high-fire philosophy.

edifice rex said...

Hey Karl! I don't guess I have heard their version. :)
Yes, power can come from green sources; I was just thinking of my present situation. I really wonder though, how large of a solar array would be required to power this kiln. I imagine it would take quite a lot.

Hey Jim! thanks! it is good for the heart and soul. :)

Hey Anon! yeah, you have to weigh it all and it can get mind-boggling! Since I have almost 20 acres I figure I could raise enough of my own wood to kinda cancel out the environmental affect. Wood is very renewable. But yeah, it goes on and on...
Thanks! yes, the Fairhope show is very good. I've been but have never been an exhibitor. Maybe one day.

Hey Jojo! Great!! I glad you like them!

Hey Jenn! Oh, thanks so much!! I'm glad you are happy with them.

Beatrice P. Boyd said...

ENjoyed reading about the kiln and firing process, Annie. I've never done anything with cermaics, but have an appreciation for all that goes into producing such beautiful and useful pieces.

ignatz said...

Used to have an L&L, sold it for $100 when it was 20 years old!!! They are work horses. How are you venting your fumes?
As to woodfiring, the carbon footprint is HUGE and the results really, really depend on where your pieces are in the kiln, electric is more predictable and economical if you're trying to make a living, what with less loss per load. I figure you balance your electric use with other green habits. I don't know much about gas firing, did that in college in the 70's, maybe that's why I don't remember,but I DO know about high-fire snobs. There are snobs in every segment of everything we do, poor souls. Looking forward to my mid-fire red bowls :)

ignatz said...

one more thing, those plate shelves are great! but those full shelves must be heavy suckers, watch your back with those babies, I have half shelves, makes the lift gentler on the aging bod

edifice rex said...

Hey Beatrice! thanks! glad you enjoyed it.

Hey Page! aren't L&L's great!? I love mine. yeah, I'm sure you do know about the snobs. Seems to me they are worse in the clay circles than in some of the other crafts.
Yes, electric firing is much more reliable; we did a little wood firing when I was in school, learned about it's cold spots! Gas is pretty reliable once you figure out what you're doing.

I use one of those kiln vents that mount underneath, pulls the fumes down and out. Also helps to produce a more even firing. I think it works good.
The shelves are a little heavy but not terrible although I have thought about getting some of those half shelves. Keep in mind I used to tote steel for a living but, as you say, bending over to put one at the bottom of the kiln is sometimes rough on the back!

Jenn said...

Regarding a solar array - yes, it would take a lot of panels to fire a kiln, but remember this - most of the time your panels would be collecting, they'd be feeding the grid, as you use so little energy day to day.

So when you fire it up, you'll be pulling back the electricity from the grid. Depending on your solar exposure, you could come out ahead.

It would, at any rate, give you a nice offset.

Too bad those things are SO expensive!