PID Temperature Controller for Lead Pot/Luber etc.

[hunter64]

Always had a hard time controlling my Lee Lead pot with the temperature knob. If you are making solid bullets then it is a hit and miss method of finding the correct temperature, not frosted yet hot enough to fill completely. You are constantly adjusting the temp knob down and up. If you are making hollow point bullets then may the force be with you because you will have a lot of rejects until you hit the sweet spot as far as how hot the lead has to be to fill the HP fully.

So being a real tight wad I decided to take the plunge and put together a PID controller with as much used parts as I could find and getting new parts off ebay to help keep costs lower.

Parts List:
PID Controller. Type this in on ebay and you will find lots of them from 18.00 up. Mine was $20.00 for a single controller.

SSR. Solid State relay. Here again ebay for various sizes. Look at what you want to control and usually go 1.5 times the rated output to keep you safe. i.e if you want to control a 500watt Lee Lead pot then you need to do a little math. Power=Voltage x Current so we have 500=110 x current or I=4.54 Amps so go for 7 Amp SSR or higher. Mine was $8.00

Thermocouple. You need a high temperature one that goes to at least 800 F. Do you want to put it in the lead or have an external probe it is up to you. The ones that go in the lead are 3x more expensive as the external ones. I bought a cheap K type with spade connectors for $4 bucks. The external one will have to me mounted so the tip is touching the inside pot for a more accurate reading but it is really close.

Power Supply. You need a power supply that will turn on the SSR, usually anything from 3v-32v DC and at least 100mA depending on your SSR. I had an old cell phone charger that put out 5v 1/2 amp which is more than enough.

Fuse holder. $2.00 bucks at Princess Auto
Wire Connection block and spade connectors. $6 Bucks at Princess Auto.
Plug Adapter. Free
Project box. Free.
About $50.00 to control my Led Pot/Lube sizer and anything else I want to.

I recently visited an eco station where people were throwing out old computers so I helped myself to one. I took out the power supply and I will use this as my project box. Now if you are having a hard time finding a power supply well you now have one inside the box. I thought it would take up to much space so I decided to use an old cell phone one instead.

Here is the Power Supply with the lid off.


With the guts out.


My Old Cell Phone Charger.


Cell Phone Charger with top off. Two wires on right were 110v and left 5v DC.


I used a dremel tool to make the cuts in the box to fit the power plug, PID Controller, and screws and bolts to secure the other hardware.

The cell phone power supply I literally tie wrapped it in to place.

In the center I have a connection block which makes it easier to run the wires to and from. You could solder each connection but some of them have 4 wires and that gets messy.
I mounted the SSR with some heat grease on the bottom and use the box as a heat sink. I have used it a couple of times for 10 hours on end and there is no heat at all that I can feel with my hand.

On the front I mounted the PID the power connection and the thermocouple block so I could change thermocouples easier depending on what I want to do with it.

Side view. You can see the power supply on/off switch and plug in for the computer power cord.


Top View. On the left you can see the fuse holder and in the middle is the connection block.


Right side view. On the left is the PID controller, below it is the tie wrapped in power supply and on the right is the SSR.


Front view. Top left is where you plug in the Lead pot/Lube sizer etc. Below it is the thermocouple connection box and to the right is the PID.


Closer from the top. You can see the fuse holder and the connection block better. You will notice that the connection block has three position strips on it and I am only using two. All the equipment that I am controlling with this has only a hot and common and no ground so I left it open. Same with the plug in, no ground. The power supply came grounded to the chassis so I left it there.


Schematic that I used to wire it up. There are lots of different versions over on Castboolits web site but this is for my controller.


Now how I use it is I have mounted a female end to the thermocouple on the bottom of the pot. I screw in the thermocouple and hook up the wires on the front. I plug the 110v power cord from the pot into the front and set the temperature on the pot to the highest setting. I turn on the power switch at the back of the box and the PID asks me to input a set point (temperature I want). I push the up arrow until I get 800 F and that is it.

I have set the parameters on the PID for a 5 deg. swing so it is off at 806 F and on at 794 F. You can set it for 1 deg if you want but the SSR would be constantly on and off.

I am telling you I have never made hollow point bullets with so much ease as with this controlled temperature wonder. Usually I would get at least 30% reject rate and now I am down to under 5%.

As for the Lube sizer it is a dream. I set the temp I want and leave it, no more turning on and off, guessing when the lube will be to hot and runny or to cold.

Wish I had done this years ago.

I have even hooked this up to my electric meat drier/smoker with great results. I enter the amount of time I want it to run on the PID (timer function) the temperature I want and go to bed, in the morning it is done to perfection.

 

[Pete04]

Great work!
Thanks for sharing.

 

[phishroy]

Great instructions will be one of my next projects.
I find with my lee bottom drip drip drip… as the amount of lead goes down in the pot during the casting session the temp’ goes up and I always need to keep a very close eye on it with a candy thermometer .

I find that if I start with a full pot of lead at the begging of the session at about setting 3 or 4 by the time im half way down the pot I need to bring the setting down to 1 or 2 or add more lead to the pot which freezes the pot and starts a whole ordeal of frustrations within itself with the bottom drip drip drip getting clogged.


The lee pot owners out there probably know exactly what im talking about.

Thank you for the instructions this gadget will come in very handy to my needs.

 

[Waba]

hunter 64, thanks for posting your system. Its an ingenious and elegant solution that would certainly make casting more predictable.

 

[hunter64]

Great instructions will be one of my next projects.
I find with my lee bottom drip drip drip… as the amount of lead goes down in the pot during the casting session the temp’ goes up and I always need to keep a very close eye on it with a candy thermometer .

I find that if I start with a full pot of lead at the begging of the session at about setting 3 or 4 by the time im half way down the pot I need to bring the setting down to 1 or 2 or add more lead to the pot which freezes the pot and starts a whole ordeal of frustrations within itself with the bottom drip drip drip getting clogged.


The lee pot owners out there probably know exactly what im talking about.

Thank you for the instructions this gadget will come in very handy to my needs.

Two things I have found to help with the Lee Drip-O-Matic. Clean out the pot and with the lever assembly removed so you just have the shaft with the rounded end that goes in the orifice.

Take some valve grinding paste that you use to seat valves on heads (gritty) and put a little bit of that stuff on the end of the rod. Now chuck the rod in a hand held drill and position it as if you are using it normally in the pot and you are pouring lead. On a slow speed slowly turn the rod in the drill and as you are doing this you are slowly sanding down some of the imperfections in the orifice and the rod. Don't go hog wild, just a very slow speed, wipe off the end of the rod, put some more grease on there and do it again. You will see on the end of the rod that a smooth portion will appear where it was not round before.

After cleaning all the gunk out of the pot , put it back together and add some more weight to the end of the lever that you lift. I used a piece of pipe that I drilled a whole in, anything to add more weight.

You will now notice that you will hardly get any dripping as compared to before.

With the PID controller you just set the temp you want, put the lee pot on max and forget about it. Now all you have to do is figure out the correct amount of time between pours into your mold and you have the world by the tail.

 

[hunter64]

Just a quick update on the use of the thermocouples that you can buy both the internal ones that go in the lead and the external ones.

I welded up a bung on the bottom of my Lee pot, basically a piece of steel that I threaded the same as the thermocouple 1/4 x 20. I hooked up the thermocouple to the PID controller screwed in the thermocouple so the end was touching the outside of the pot on the inside of the shroud (if that made sense) and took it for a spin. I was kind of wondering how accurate an outside measurement would be compared to an in the lead measurement so I put in my lyman thermometer to check the temp. Well it was way off almost 200 deg F lower than the in lead temp said on the dial.

Not really believing that the external could be off that much a borrowed a digital thermometer from work that goes to 1800 deg f and it matched with in 10 deg f of what the lyman thermometer said.

Next I rigged up a thermocouple holder for the top of the lee pot so the end of the probe would be 1/2" off the bottom and sides of the pot for best accuracy.

Now we are talking, the lyman thermometer said 750 deg, the digital thermometer said 755 deg and the PID controller turned the pot off at 753 deg. All within 5 deg which is a heck of a lot closer than a 1-9 dial setting.

I noticed that when the pot goes off the temp will continue to rise about 15 deg and then drop past the turn off point at which the PID turns on but it still drops about 10 deg before returning to the proper temp. After 5 cycles I also noticed that this 25 deg swing was reduced to about 10 deg as the controller is learning the correct settings.

As far as the external thermocouple goes I mounted it my luber, no more plugging in a heat source and then unplugging it 20 min then repeating until you are done. Just set and forget.

Really cool and well worth it.