PID on heat treating oven?

[Mk42gunner]

Reading tomme boys heat treating thread gave me a question.

Has anyone ever ran their heat treating oven with a PID?

I do not have a PID, they haven't really seemed necessary to me just for casting. Likewise, I don't water drop or oven heat treat. ACWW does most of what I want to do with cast boolits, so this is mostly theoretical for me.

Since every thread or article I can remember reading has stressed testing the slump temp of your alloy since oven temperature settings are unreliable, doesn't it make more sense to use a PID to control the oven?

Seems like it would be ridiculously easy to install a thermocouple and wire it in.

Robert

[dragon813gt]

You can do it easily. Just remember that a PID has to be tuned for whatever device you use it on. An empty oven is going to gain/lose heat a lot differently then a full one. Like you said you would just have to install a thermocouple in the oven, tune it and you're off.

[RobS]

Works very well actually and as been stated you need to "learn" your PID for the oven. I use mine for both my pot and my oven and once learned I simply wrote down the PID settings and then input them each time I change from the oven to the pot (a simple 15 or so second change in settings). I use the same thermocoupler and drilled a hole in the top of my oven the size of the probe and did the same on the lead pot lid. If you have a convection oven with a fan you may want to straight wire the small fan so you don't burn it out with the on/off functioning of the PID controller..........that's what I did anyway.

[Mk42gunner]

I knew somebody else had to have thought of this; we are a pretty innovative bunch here. It is just that I had never read about it, or retained the idea if I did read about it.

Robert

[Mike W1]

Works very well actually and as been stated you need to "learn" your PID for the oven. I use mine for both my pot and my oven and once learned I simply wrote down the PID settings and then input them each time I change from the oven to the pot (a simple 15 or so second change in settings). I use the same thermocoupler and drilled a hole in the top of my oven the size of the probe and did the same on the lead pot lid. If you have a convection oven with a fan you may want to straight wire the small fan so you don't burn it out with the on/off functioning of the PID controller..........that's what I did anyway.

I don't have any interest at the time in heat treating but am curious about your TC probe. Same immersible type you use in your lead pot I believe you said. I'd think there must be a probe maybe better suited to the task though I don't know just which type it would be.

[RobS]

I don't have any interest at the time in heat treating but am curious about your TC probe. Same immersible type you use in your lead pot I believe you said. I'd think there must be a probe maybe better suited to the task though I don't know just which type it would be.

Yep same thermocoupler probe and there's no problem keeping my oven on spot as you can see by the picture. I'm annealing some boolits down from a harder water quench from the mold. 250 degree is my setting and once up to temp the PID with that probe will keep it at 250.0 to about 250.3 maximal.

Type K thermocouple high temp. -100 to 1250 degrees Celsius IIRC

[5Shot]

I purchased a Lab Oven off Craigslist for this purpose. A PID for it is the next step.

[RED333]

I use an analog dial gauge to see the temp, works well.
I let the oven preheat, then cycle 3 or 4 times and it will hold that temp.
The little unit does well, I have not done any HT just yet, just PC.
The oven does drop temp for a few mins, after I load it, but it is just less that 2 or 3 mins.
Them back up to temp for the rest of the time frame.

[jaysouth]

I had this idea once upon a time, but found out that you had to rewire the oven to make the PID work. I was not smart enough to figure it out.

My hand me down toaster oven burnt up and I went to Walmart and spent $49 on an Oster convection oven. It holds temp and does a great job at curing PC bullets. I marked my calendar when the one year warranty is up, just in case I kept the box and receipt. Walmart is very generous on returns.