Tips for controlling heat using only element on/off switches?

[Tacit-Trouble]

I took a pottery class last fall and it set me on fire!  I picked up a Dickinson manual kiln guesstimated from the 70s (so old its been hard to find any info on this kiln/manufacturer).  It uses a LT-3 Kiln sitter and 220v 26amp.  It has been super fun to restore it!

It has 6 elements, wired in 3 pairs - each pair has an on/off switch.  So once the kiln sitter is set, the kiln heat is controlled using one/more of these 3 switches.  I put a pyrometer in one of the peep holes to monitor the temperature.

Its been tricky to control the heating.  I have to flip a switch on, check temp frequently to monitor heat increase and then turn it off to slow the heating down.   

Anyone have experience using a old kiln with just element on/off switches - with some tips for managing heat this way?

thanks 

 

 

[neilestrick]

Don't worry about it heating evenly as it climbs. It'll all even out in the end. Make sure your work is totally dry before loading, then:

1. Prop lid open an inch or two and turn the bottom switch on for an hour.

2. Close lid, wait 1 hour.

3. Turn on middles switch, wait 1 hour.

4. Turn on top switch till the cone bends and it shuts off.

I used this schedule on my old Evenheat kiln that only had on/off switches and it worked great.

If you want more control, swap out the on/off switches for infinite switches.

FYI, one regular household voltage- 240 volts- the kiln is going to pull a little over 28 amps. Code requires that kilns must be on a breaker that is rated 25% greater than the draw of the kiln, so it should be on a 40 amp breaker, with appropriately sized wires, and have a 40 amp power cord and outlet.