Looking for Tips, Advice, and Direction on Temp Control

[curtis K]

Looking for Tips, Advice, and Direction on Temp Control

I recently purchased a used Johnson 102 blown gas forge. This thing is a jewel other than the time needed to get it up to working temp. I would like to install a temperature control unit but I do not want to buy the one from Johnson which is in excess of $1000.00. Any direction would be appreciated.

Thanks,
Curtis K.

 

[Stacy E. Apelt - Bladesmith]

Add a PID controller, an SSR, a type K thermocouple, and a solenoid valve. Cost will be about $100. Ebay has all of them, or you can get the PID and TC stuff from Omega or Auberins and the solenoid valve from any gas valve supply. Make sure the valve is rated for LP gas.

Here is an old thread where I explain my two-stage controller plan. Read all the way through the thread, as the info is in several different posts:
http://www.bladeforums.com/forums/showthread.php?t=635924
and another on the subject:
http://www.bladeforums.com/forums/showthread.php?t=523845

Using a ceramic thermocouple well (sheath/tube) for the TC will make it last a lot longer.

If you think all that stuff on the data sheet that comes with a PID is confusing junk, here is an article I came across while searching Auburn Universities papers. It is totally for the engineer/geek types, but it shows you how much actually goes into the design of those $30 controllers:
http://www.eng.auburn.edu/users/jzw0001/chen4170/Chapter_8.pdf