Randall you cant hear him but he is calmly requesting his other glove while I take a couple pictures. At 1200 degrees and up the glass came loose from the chuck and out the kiln, fortunately no one was hurt and no damage was taken. Excessive heat on the one inch thick blank caused a increase in decent speed and took us both by surprise.
Heat distribution is a crucial element with all the heat rising to the top, going to far or to fast ends in disastrous results. The controller that we have is capable of running three zones although some fancy programming may be required. Unfortunately the controller is only able to accept one thermocouple so heat sensing only comes from one point. Additional thermocouples may be used to tell temperature in other areas of the kiln but wont provide the info to the controller only to us for calibration. Other methods are also being explored but a quick re wiring of the kiln and an additional mercury contactor give us three zones, The top two sets of heating coils are the same size in electrical load and the bottom set is the combined load.
The new enclosures are far simpler and mounted closer to the coil attachment. They will double as an attachment point for a arch shield to protect users and wiring.
Wobbling on a high note has been all but eliminated by two things, one a reduced speed motor going from 64 RPM to 9 RPM and still using only half the speed and two the reinforcing bearings at the top of the kiln. The bearings that were added worked at high speed but torque and poor speed control were still issues at high speed.
The info that we collected led us to many improvements it is nice that the first one worked out but learning from failure is perhaps more productive than getting a bunch of four foot ......tube socks.
This is an ongoing project melding design and development, ultimately this prototype will provide the knowledge necessary for a big kiln. Yea I said BIG and fancy, we are talking about an entire setup and process to support making massive elaborate vessels. Fun stuff.
Currently I use three rolling carts one is 1/2 inch steel plate 3'*6' and is used primarily for welding and grinding it also works well for mounting other tools and things. Herman and Cade are helping me bend pipe for the Wankel Bell with the bender mounted to the metal cart.
Monday should be our first real test fire and Tuesday dropping our first glass. While building this Super Kiln I have labored to keep things as flexible as possible. This allows for alterations, additions and need be fixes. The necking device is next on the build list and it will be fancy.
The tread bracket fits between the two plates and is welded in place level to provide a support for the tread.
In this design the treads provide a significant stiffening element. The steel itself is stiff on edge providing plenty of support but horizontally the stringers can flex.
The treads limit this flex by transferring the force on the circumference of the stringers and by creating a boxing effect between the stringers and the treads.
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