It had to happen sooner or later.... thanks to Conditor22 and a generous surprise package that showed up this morning. He and I made a horse-trade for one of his spare Lee 10 pound furnaces. In that box he included a Rex C100 PID, a solid state relay, a thermocouple and a fuse enclosure...had no idea these controls were coming!
Thank you Jim, I appreciate this very much.
I decided to gut all the controls but the 'ON - OFF - Timer Set' switch and the pilot light. I removed the 'thermostat & dial temp. setting' and the 'selector switch' that selected the upper and lower heat elements and controlled the fan. I cut the lower set of elements out permanently and wired it back using the upper element only. It is a small oven, the upper elements are all I needed.
Everything tucked in nicely to the vented control area of the side panel...vents are bottom, side and back...
Only one test so far...as it is empty, 180ºC = 400ºƒ...
the thermocouple is in the rear on the right side 1.5" above the tray...
Heated air is drawn into the fan across the top of the tray on the right at the same level the thermocouple is mounted and is blown out from the top slots between the elements and that is the circulation. Heated air also blows out the bottom slots between the now defunct lower elements to heat the tray from the bottom...
There was plenty room in the back area of the enclosure for the thermocouple and the solid state relay...
In the front is the PID...fan in the middle...
Only thing left now is to take another PID I have and put the thermocouple in the control area now that's now closed up and monitor the temperature there while in operation. I think these controls are rated at max. 75ºC/167ºƒ. If the control area exceeds that I will insulate the oven wall side of the enclosure and add a small fan to the rear to pull in fresh cool air. This should take care of any overheating of the controls.
After that, I'll load the tray full of 230 gn. 45 casts and find out how long I need to set the timer for a single batch starting from a cold oven.
I think I've pretty much covered all the angles but if one of you fellas see something I've overlooked, please bring it up in a comment.