There’s been some threads on this forum about casting pots that eventually includes a discussion on PID controllers which are now standard features in RCBS & Lyman pots & likely others.  I posted a couple of articles on my website some time ago on PIDs & thought I’d post a photo here of a simple PID schematic for those that may consider making their own.  The two articles can be accessed at the following links:
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I mentioned in another thread recently that PIDs designed for casting pot can be relatively simple.  All the necessary parts are readily available on eBay, Amazon and/or several suppliers for $50 to $100.  You’ll need the main controller, solid state relay (SSR), heat sink, appropriate thermocouple, on/off switch, fuse/fuse holder, terminal strip, power cord, AC socket and small project box.  All of this is discussed on numerous Internet sites and in several threads on the Cast Boolits forum.  Following is one persons (not mine) schematic of a PID he built.

Wayne

Although useful to remind you the PID & the pot are both on the lamps are not necessary for functionality.  The solid state relay must be rated to handle the maximum current required by the casting pot.  BTW, if it's not clear, wires B & C supply the 110V power to the PID.

So, the thermocouple sends temp. signals to the PID.  Based on the PID settings the PID sends control signals to the SSR via the blue wires 7 & 8 and determines when to activate the SSR to send 110V to the pot heater.  Pretty simple.  All the complicated decision making stuff is handled by the PID.

Wayne

bnice wrote on Nov 26^th, 2021 at 4:50pm:


Type K or J will both work in lead ranges. The J actually would work better with a 750c. max. vs. the K at 1250 c. max.

MC One Shot wrote on Nov 26^th, 2021 at 11:00pm:


So where/whom did you order it from?  I assume you mean a complete ready to use unit, not just the PID.

Wayne

texasmac wrote on Nov 27^th, 2021 at 1:04am:


Thermomart....I called them told them what I needed it for and the lady was well informed.

Art, not really, a PID monitors and controls the temp. A dimmer just varies the power to the pot like a water faucet with no intelligent control.

I built a PID for my pot, for the most part its not hard to build one at home. As a bit of a disclamer I am a retired toolmaker so the metal work involved was easy to me. The electronics were where I had the most problem but I did find a diagram similar to what was posted here and managed to work my way through things.  There is a bit of a learning curve to figure out the functions on the controller its self. But that was minimal. Its nice to just punch in a temp change and wait a bit for it to come up to what you want and then it pretty much stays there as you cast. If you are running too hot, it takes a little longer to lower the temp but it will get there. 
For a power cord I kind of went the cheap way, I had some left over brand new computer power cords and installed a plug into m box that these cords would plug into, simple solution in my mind. You could also cut off one end of the cord and hard wire it in place if you want. 
Sam

MC One Shot wrote on Nov 27^th, 2021 at 4:46am:


I assume you bought one of their kits.  Hopefully the thermocouple will have a long probe that can be inserted into the melted lead in your casting pot.  Thermocouples come in many different configurations.

Wayne