Kiln

[Dalton Knapper]

I think you're in business, especially since you don't have to mess with 220V. Great for you!

[JoJoDapyro]

Here are some Photos. I don't really have an issue with 220, as my garage is wired for it. The previous owner ran a machine shop out of the garage. The Unit measures 20 inches square (not counting the place the switches are) and is about 12 X 12 on the inside. It is a heavy beast, I would bet about 200 pounds. So here are a few more questions. How hot do these units tend to get on the outside. It seems very well insulated. I guess my question is, Attic or garage use?

[caveman2533]

Wow, that's a big one.  I would say this to you, If you are serious about heating a lot of rock, Invest the money that you saved by buying this so cheap, into a computerized  programmable controller.  The problem with an infinite switch is this. It is mounted outside the kiln. It in no way is controlled by the temp of the kiln.  There is no thermocouple that controls it and says switch on and off. It is a bimetallic coil strip,(In the switch) that opens and closes the contacts by heating up due to the current coursing thru it. It then reaches a predetermined setting H, M, or L and then when it gets hot enough it opens. When it cools off it closes and starts all over.  Just like your stove top switch that controls the burner. In fact the switch on your stove is what you want for one.  If it is cold outside where you live it will open and close more often than it should and cause the temp to rise faster and hotter than you would like it.  An infinite switch means you will infinitely be babysitting your kiln.  Trust me blowing up one load of stone will pay for your controller. You most likely will not need to use all the elements in that kiln either. Mine has four and I turn the bottom and the top one on.

[JoJoDapyro]

Thanks for that info caveman. I have been going over in my mind how to get this thing to work for what I need it for. I have been questioning the electrician at my work about high amperage timers and such. If you could find the rate of heat up, and cool down you could figure out a way to set the timer that would hold at a certain temperature, and could conceivably even factor in ramp up and down temps as well. I wasn't really in a hurry, but I guess my coworker wants it out of his shed (It has been in there for 17 years  ) and since he knows where I work isn't too worried. I will pick it up this weekend.

No one has hit on where to use it? Garage, or attic? Getting it in the attic will be the only issue. 12 foot garage ceilings and 200 pound kilns aren't friends   

[caveman2533]

I don't think I would put it in the attic. Sounds like a fire hazard. I have never had any issues with that but don' want the rest of the house to go if it would.

[Dalton Knapper]

Definately a garage item. Listen to Caveman on his conttroller advice, he has loads of experience in these matters. I have a 220 V kiln hat is basically worthless to me as a knapper. My vintage turkey roaster is however very useful.

[JoJoDapyro]

Over the weekend I talked to an electronics engineer. Kinda made me feel dumb. All I need to make this kiln into an adjustable kiln is a Potentiometer, and a pyrometer. Quite simply, install the potentiometer in line, and use the pyrometer to mark what position on the switch is what temp.  Both can be picked up for around a hundred bucks.

[caveman2533]

That will make it adjustable but it will still need to  be babysat

[JoJoDapyro]

True. But $100 and some baby sitting is better for me than $500 for a digital controller.

[mullet]

Mine has a high, med, and low setting. I brought home a thermometer from work and plugged in in on low. I left the lid half off and checked the temp at the top and bottom and kept sliding the lid closed til I got the temperature I wanted. And that's the method I use and it works fine. I'm cheap, too. The first time I used it I heat treated some coral in 2 1/2 hours. I turned it on low, closed the lid and turned it off and opened the top when I heard the Texas Perd's blowing up that I had put in with the coral. The coral was perfect.

[JoJoDapyro]

Maybe I'll try that. I don't know how high the pyrometers go that I have here at work. I'll have to take a look. The guy I got it from said it went to 1200 and 2000, but it doesn't seem like it gets to 1200. It also ramps up very slowly. I have a few buddies who are very good with electronics, and a few who went to school for it and should be, but I guess they like delivering Pizza more. I do all the soldering work for them whenever they need it.

[Chippintuff]

I have no idea about rhyolite and the other tough rocks, but most chert and flint can be heated very well in a turkey roaster. Just 30-50 degrees too hot can explode most cherts and flints. I had an old kiln with an "infinite" control. I even turned some chert to sand using the lowest setting on it. My suggestion is to use only heat units that have accurate temp control via a thermocouple/thermostat.

WA

[mullet]

Once I saw where the lid needed to be for coral and chert I started using my thermometer for BBQing. Most of them go to over 500dgs.