Thanks for the kudo's. The kiln is home built. The internal firing dimensions are 4' x 4' x 17". There is a 2" space from the shelves to the wall inside so the total internal space is 26.6 cuft. I sized the power at 1KW/cuft so the total power capability is 26.6KW.
There are a number of specific requirements I was looking for which drove the design. Since I work alone, as do most of us, I wanted to be able to be able to maintain the kiln by myself. In addition, in just building the darn thing the top weighs in at around 700lbs. That is not something you easily flip over with a bunch of your buddies, at least not doing so and remain friends. As you can see from the one picture, the kiln has a maintenance mode where the bottom is wheeled away, 3/4" stainless pins are inserted from the side into 2" bungs tig welded to the top. The power and thermocouple cables are unplugged and the entire assembly can be rotated. This can all be safely done by one person. The rotation axis is pretty close to the CG so it moves pretty smoothly.
I built it with two moveable bottoms so I can be firing on one and building another. After I got into this, I thought that that is probably not necessary but knowing how I work (quite ADD) I like to work on multiple types of things at a time, it will probably work well for my style. Based upon lots of discussion on the board, both on the pro's and con's of wheeled bottoms, I constructed the top such that I can safely work directly under the bell when it is in the up position. Not shown in the picture (last things to be done), there is a beam that goes across the top and channel locks to the uprights on the hoist. This beam is bolted to the top and can be locked in position with 3/4" stainless pins. The bell is lifted by the hoist and then held in place by the pins. This way the load is removed from the hoist and is pretty much failsafe. The bell can be lifted high enough that I can get my 6'1" underneath without hitting the bell.
On the insulation side, it has 2" of Thermo12 board insulation on the outside with 2" of fiber blanket on the inside. The bottoms are made of K23 firebrick placed and locked tight on a steel bottom. The bottoms have wheels on adjustable vertical threads so they can be leveled easily. Once the initial "dust" has setteled, I intend to bolt steel guides in the floor so the bottoms can be easily wheeled to the exact postition every time. For now I just have to manuver them a little more.
On the control side, the main controller is from Orton. This is the same controller Paragon uses on their larger kilns. It's what I'm use to as my other kilns are Paragon so for me I'd rather not be confused with different programming methods. The main power is switched using Mercury Displacement relays. These relays cannot fail in the on position, though the can fail. I have a backup controller from Omega. I took a kiln class from Larry Fiedler (good instructor BTW) and he uses setpoint controllers from Omega. I looked at using one of these but for just a few bucks more I was able to get a setpoint controller that can also work as a limited controller itself. For what I spent and for what a full load of glass costs I figured it was cheap insurance to have an overtemp kill controller. Even though the merc relays shouldn't fail, there are relays in the Orton controller and ones that drive the merc relays so there are still potential failure points. Also, if the Orton blows out for some reason, I still have a controller I can fire with while I get a replacement.
I was interested from a design standpoint wrt the insulation scheme and there was little "hard" data other than just experience. This is not bad but difficult to design from if materials are different or your kiln requirements vary so while I was stuffing my kiln I embedded a bunch of thermocouples at different layers and locations inside the bell. This is why there is such a collection of thermocouples. I intend to take a lot a data and publish both the data and hopefully come up with a little better model for people to use in future designs.
My web site should be up in a few months and I will have all of the particulars on my design and how well it is working. There are a lot of details with respect to safety, noise, etc. that I won't cover here but I'll have writeups later on my site.
Phil
PS - Just for the curious, I've spent about $8,000 for everything. It's been about an even split of 1/3-1/3-1/3 for insulation, electrical, steel&hardware. I've looked around at professional models and if you got exactly what I got, delivered to your studio, wired to your electrical system and set up running, you would spend at least 2x to 3x this price if not more.
PPS - Oh, yea, about 1 million or so man hours too between me and my son
