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All Springer/NP/PCP Air Gun Discussion General => Projectiles => Boolit and Pellet Casting => Topic started by: Greg_E on January 28, 2022, 11:13:08 PM

Title: PID controller for lead melting pots?
Post by: Greg_E on January 28, 2022, 11:13:08 PM
Anyone want to start us off with parts, knowledge, etc. on making a PID control for our lead melting pots?
Title: Re: PID controller for lead melting pots?
Post by: triggertreat on January 29, 2022, 12:32:23 AM
Here's the one I built and some videos of how to build it and where to get the parts:

1st attempt - Airguns & Guns Forum (gatewaytoairguns.org) (https://www.gatewaytoairguns.org/GTA/index.php?topic=158723.msg155780761#msg155780761)
Title: Re: PID controller for lead melting pots?
Post by: Firewalker on January 29, 2022, 01:26:00 AM
Anyone want to start us off with parts, knowledge, etc. on making a PID control for our lead melting pots?

It's much easier and harder than you would think. I used the Inkbird kit: https://www.amazon.com/Inkbird-Thermostat-Temperature-Controller-Thermocouple/dp/B01489AQAW/ref=sr_1_21?crid=3MH9FVWXHVYUW&keywords=pid+controller&qid=1643431968&sprefix=pid+controller%2Caps%2C216&sr=8-21 (https://www.amazon.com/Inkbird-Thermostat-Temperature-Controller-Thermocouple/dp/B01489AQAW/ref=sr_1_21?crid=3MH9FVWXHVYUW&keywords=pid+controller&qid=1643431968&sprefix=pid+controller%2Caps%2C216&sr=8-21)

This kit will control the lead temp up to 752° F. I also decided to tap the bottom of the pot (LEE #10 bottom pour) for the K Thermocouple near the spout.
Title: Re: PID controller for lead melting pots?
Post by: triggertreat on January 29, 2022, 01:45:33 AM
I bought my PID controller and K probe and SSR (40 amp) off of eBay along with an old computer power supply I used for a case.  It's not that hard to build but did have to wait for China shipping a few weeks.  Just follow the videos I linked.  This PID has a range up to 999° and I like how it works and this one is stateside.

TA4-SNR RNR SSR Digital PID Temperature Controller Relay Output Dual Display AC | eBay (https://www.ebay.com/itm/284361294057?_trkparms=ispr%3D1&hash=item42354100e9:g:XYoAAOSwVGdg5BJe&amdata=enc%3AAQAGAAACwPYe5NmHp%252B2JMhMi7yxGiTJkPrKr5t53CooMSQt2orsSwcmzw5CLtzTE60FqHcnq2HGKiKhSXxU8It1jBTeVSZfsNyvLda%252FqiYQiOD5UiasjXh4%252F0ridPF%252BWYelEMgUSxc%252BIm9kz3PlGNkDjprRUqYKDrPzmsTprg1DQijFu2pi4rdMpxCJkqhxXTpIryeKoWbMsPT%252BQKsnVnZtcIT5RO6CCDUeWH2Wzw4dBKSCcUSMqTQwkUlx55qpVHJuyfh6hGJT4YO78dyKswy96xufYBA7cXv5FZlERgGaGwxQt6%252F74lHvZVfUncgajXJWuNTX6%252FPrDsUFqNUyqy4yBneQqOXKKOzmcCLLhl6YM2Ha6Jx3Q9%252BvaBzGM65jhl1x1s53zdG1S%252BE4Pj5myB3Pe52mOEaPY%252FLwhhBire2dZdRdrSvrjMkC8%252BphYawhLiNn1VT7ECmMkrydg%252F8BhZn6nIFWRaNde%252BB8GfPwOeKDcqTSCAvAfabDxp8etEAVFLMyqBSitZXHZIa9yqJ%252BxX4C%252FplkYESQlkruiMqwwlbibBBLH3d%252F23cXwdvklbvHh3AWgmKTXLs7r3WFcnnK3vuHDHmpmuRrSCqJtYlRmb8F%252F2FT%252BM4S%252BdUEmF%252F5WRe7Ixc3OcRiJZKNGvd%252FQCjfFXHSXuMiG1iv4U5NVlBhO62UFgjTewmFB%252BkxYoIlk1wEm2v4swFK%252FVGBGG07Z5bpkA%252BJ0BUEu5v2vDGdQcTeB1fNYoK6cx42giSifse5GItudn5LE3%252BUPLFzXjZ48q2AtKdvcOswF9fUzRp2hfGFg4ukmXhZCJ8z5r%252FdoFkzY%252FVPbl239RasC2Z2%252BEUypDOlfin1tqzL%252BvAXGzU%252Fr282VhgdeP%252BuHbYnYLMSVK%252F2s9SKN6Mi0icwnIEu6w79kR9D5u4SaBWo3N9l7drjh83jUsJ8UUADyDHfo%7Cclp%3A2334524%7Ctkp%3ABFBM-qesxdRf)
Title: Re: PID controller for lead melting pots?
Post by: Bob Pratl on January 29, 2022, 06:19:05 AM
A PID is a good way to eliminate heat variations which will result in more consistent casting, "Set-it-and-forget-it".
Title: Re: PID controller for lead melting pots?
Post by: rkr on January 29, 2022, 07:35:30 AM
Auber is a reliable source https://www.auberins.com/index.php?main_page=product_info&cPath=99&products_id=1016 (https://www.auberins.com/index.php?main_page=product_info&cPath=99&products_id=1016)
Title: Re: PID controller for lead melting pots?
Post by: scion19801 on January 29, 2022, 11:27:06 AM
here are some of the random pics I took of my PID controller as I was building it and how I set mine up. the plug socket on the back is split. one(bottom port) is always powered and uncontrolled. the other(top port) is the pid controlled for the pot to hook into. well based on my pic the ports would be reversed given the orientation. but when in use the ports are as stated.
the top and bottom are aluminum plate. the black square on the bottom is the heat sink for the relay.
Title: Re: PID controller for lead melting pots?
Post by: triggertreat on January 29, 2022, 12:45:06 PM
Auber is a reliable source https://www.auberins.com/index.php?main_page=product_info&cPath=99&products_id=1016 (https://www.auberins.com/index.php?main_page=product_info&cPath=99&products_id=1016)


This is a very good deal and comes with the type of K probe needed along with the heat sink for the solid-state relay and thermal grease.  I am surprised at the low cost.  An on/off switch, some wires and terminal strips along with the panel mount socket for the thermo couple and an A/C socket and fuse holders and a box to put it all in is about all that is needed besides this kit.
Title: Re: PID controller for lead melting pots?
Post by: Greg_E on January 29, 2022, 11:12:10 PM
I did see some cheap cases for these controllers on amazon, didn't really investigate yet.
Title: Re: PID controller for lead melting pots?
Post by: superchikn on January 30, 2022, 12:06:50 AM
following

Title: Re: PID controller for lead melting pots?
Post by: Firewalker on January 30, 2022, 01:39:27 PM
Auber is definitely better but the cheap Amazon kits do fine for the hobbyist.
Title: Re: PID controller for lead melting pots?
Post by: customcutter on January 31, 2022, 09:39:21 AM
Auber is definitely better but the cheap Amazon kits do fine for the hobbyist.

Thanks for the comment.  I was wondering what the difference was in the kits, for almost 2X the price?  Inkbird seems to have great reviews.
Title: Re: PID controller for lead melting pots?
Post by: Greg_E on January 31, 2022, 11:19:36 AM
Is there a PID system that uses PWM to control the heating element? All of these seem to just bang the heater on and off as needed, a more tightly controlled fashion of what the stock control does.

That said I'm thinking about a PID for both my lead pot and my PC oven, also need some rock wool for the PC oven. Since I'm never running both at the same time, I may use the same box to control both, I already drilled a hole in my oven and stick my Lyman temp. probe through the hole to keep an eye on the oven temps.
Title: Re: PID controller for lead melting pots?
Post by: Bob Pratl on January 31, 2022, 01:05:06 PM
That said I'm thinking about a PID for both my lead pot and my PC oven, also need some rock wool for the PC oven. Since I'm never running both at the same time, I may use the same box to control both, I already drilled a hole in my oven and stick my Lyman temp. probe through the hole to keep an eye on the oven temps.

That is exactly what I do, one PID for 3 different sources.
A PWM controller might give you more precise control, but I don't think that it is needed for the additional expense.
Title: Re: PID controller for lead melting pots?
Post by: triggertreat on January 31, 2022, 01:29:59 PM
I agree with Bob.  The PID pulses the SSR on and off very rapidly once up to temp that it has no issue keeping up or keeping precise temps good enough for what we need for a melting pot.  The swings are very minimal if not adding lead back in as you cast and does a great job at maintaining the temp as the material decreases in quantity.
Title: Re: PID controller for lead melting pots?
Post by: Greg_E on January 31, 2022, 02:14:17 PM
Yeah, I did some reading on PID for ovens, most guys set them for about a 2 second cycle because the oven just can't react fast enough. For the lead pot I'm guessing a 1 second cycle time is probably fast enough. Need to spend some time on it and make a nice one that I can use for both devices.

Need to mod my oven too, looked into that a little bit already DEI gold tape inside, ceramic high temp insulation between the cooking box and the outside shell.
Title: Re: PID controller for lead melting pots?
Post by: Firewalker on January 31, 2022, 07:36:27 PM
Is there a PID system that uses PWM to control the heating element? All of these seem to just bang the heater on and off as needed, a more tightly controlled fashion of what the stock control does.

That said I'm thinking about a PID for both my lead pot and my PC oven, also need some rock wool for the PC oven. Since I'm never running both at the same time, I may use the same box to control both, I already drilled a hole in my oven and stick my Lyman temp. probe through the hole to keep an eye on the oven temps.

The PID is a "Proportional–integral–derivative controller (PID controller or three-term controller) is a control loop mechanism employing feedback that is widely used in industrial control systems and a variety of other applications requiring continuously modulated control. A PID controller continuously calculates an error value {\displaystyle e(t)}e(t) as the difference between a desired setpoint (SP) and a measured process variable (PV) and applies a correction based on proportional, integral, and derivative terms (denoted P, I, and D respectively), hence the name.

In practical terms, PID automatically applies an accurate and responsive correction to a control function. An everyday example is the cruise control on a car, where ascending a hill would lower speed if constant engine power were applied. The controller's PID algorithm restores the measured speed to the desired speed with minimal delay and overshoot by increasing the power output of the engine in a controlled manner."

Here is a simple video explaining the basic function.

https://www.youtube.com/watch?v=v27xYKdZUzI (https://www.youtube.com/watch?v=v27xYKdZUzI)

In reality, the PID sends a signal to the SCR and the SCR turns the power on and off as necessary to maintain your desired heat. It will 'pulse' the power faster and faster the cooler it gets until the PID is sending 100% ON signal and as it approaches, the PID sends smaller signals further and further apart. This is displayed by the red LED on the face of the PID.

I personally like PID's, I have several of them in a few different configurations for different jobs. An STC-1000 for my Logerator, a Mypin PID for my brewing boil kettle and an Inkbird in my LEE pot. No pic of the lead pot, it's in the pole barn and there is NO WAY I'm going out there until it warms up a bit.


Title: Re: PID controller for lead melting pots?
Post by: Bob Pratl on February 02, 2022, 05:09:16 AM
Not a bad price. You can tack weld or tap the bottom of your pot to accept the 1/4-20 thermocouple.

https://www.amazon.com/gp/product/B08Y8GX1WT/ref=pe_28028130_623136380_em_1p_1_lm?th=1 (https://www.amazon.com/gp/product/B08Y8GX1WT/ref=pe_28028130_623136380_em_1p_1_lm?th=1)
Title: Re: PID controller for lead melting pots?
Post by: cosmic on February 14, 2022, 03:24:12 PM
https://www.youtube.com/watch?v=SqAuBEdugcQ (https://www.youtube.com/watch?v=SqAuBEdugcQ)
Title: Re: PID controller for lead melting pots?
Post by: Greg_E on February 14, 2022, 05:06:03 PM
I may get back to this subject tonight, I need to cast up a bunch of 50 cal, or buy a bunch of 50 cal ammo. Since I have the mold in hand, lead to spare, and a sizing die, I really should get out in the garage and fire up a heater and get going. Need some more 357 too.
Title: Re: PID controller for lead melting pots?
Post by: Greg_E on February 20, 2022, 02:24:05 PM
Watched some of Johnny's reloading video, and spent some time looking for stuff. Was hoping to find a pre built unit, but the few I can find are too much money for the features offered. Lots and lots of reptile and brewing devices all nice and ready for use, but none seem to want to work at lead melting temperatures.

I'll need to do more looking before I commit one way or another, I just do not need another project right now! Far too many unfinished things to start another!
Title: Re: PID controller for lead melting pots?
Post by: triggertreat on February 20, 2022, 03:35:12 PM
Watched some of Johnny's reloading video, and spent some time looking for stuff. Was hoping to find a pre built unit, but the few I can find are too much money for the features offered. Lots and lots of reptile and brewing devices all nice and ready for use, but none seem to want to work at lead melting temperatures.

I'll need to do more looking before I commit one way or another, I just do not need another project right now! Far too many unfinished things to start another!

Don't let a PID controller hold you up from casting.  A thermometer works as well.  The PID controller is a very helpful casting tool but many cast have been made without one.  With .50 cal it's probably better to cast with what you have to save on cost as those are not nearly as critical to have perfectly matched weights as the smaller calibers are at longer ranges.
Title: Re: PID controller for lead melting pots?
Post by: DLP on February 20, 2022, 05:24:08 PM
I have made a few of these over the years. Just finished one up  a couple days ago and got to test it out this afternoon. Dumb simple to make and cheep. I suggest not to buy the $20 or less controllers. First off, they only show in celsius. Plus they are a bite to program. I like the Mipan ts4. It’s $30. And get a K type probe. You will also need a relay. All together it was less then $50. You don’t need all the wire crimps either or a cool box. Old vacuumed cord or like for 110 or 220 input. An electric plug or the heater element on the other half of the power cord for the output. I bypassed using a on/off switch and fuse and just plug it in when using. Jumper wires to each connection so you don’t need a fancy terminal block either. I did use an old metal first-aid kit to mount it all in. But doesn’t really need to be anything special. All the ones you see on the net do look nice. But that’s all the fancy boxes do is look nice. You could wrap all the electrical connections in black tape and do the same that the box does. But it is a good idea to mount the parts so they dont rattle around and short out or shock you. I also pass on drilling my melting pot to make it permanently mounted. A paper clip looped on one of the top pot screws holds the probe right next to the drop spout. I am not suggesting you make it as cheep or halfazzed as I just described. Only pointing out that it sounds like a lot more to building one than what it really is.
Title: Re: PID controller for lead melting pots?
Post by: Greg_E on February 20, 2022, 09:33:10 PM
I have a Lyman digital thermometer so nothing holding me back but time.

I was also thinking of buying enough parts to gut my powder coat baker and replace with the PID controlls, but again time to get this stuff done always seems to be against me.
Title: Re: PID controller for lead melting pots?
Post by: cosmic on February 21, 2022, 02:09:57 PM
You can build it in about an hour.. You can use a old computer power supply and gut, keep what you need and use the box to modify for your build..
Title: Re: PID controller for lead melting pots?
Post by: Greg_E on February 21, 2022, 03:03:34 PM
You can build it in about an hour.. You can use a old computer power supply and gut, keep what you need and use the box to modify for your build..

Actually, no I can't build this in about an hour. I can't just throw it together in some kind of old box with extra holes in it, just not how I do things. I could prototype this in an hour and have pieces hanging everywhere, but build it is no way. I bet it would take me at least an hour to layout the cut lines for a decent case. And another hour to cut everything out with a nibbler and drills.
Title: Re: PID controller for lead melting pots?
Post by: triggertreat on February 21, 2022, 04:29:48 PM
You can build it in about an hour.. You can use a old computer power supply and gut, keep what you need and use the box to modify for your build..

Actually, no I can't build this in about an hour. I can't just throw it together in some kind of old box with extra holes in it, just not how I do things. I could prototype this in an hour and have pieces hanging everywhere, but build it is no way. I bet it would take me at least an hour to layout the cut lines for a decent case. And another hour to cut everything out with a nibbler and drills.

Yes, that's how I went about building mine...Nibbler tool, You Tube and a lot of planning and research.  I was not in a race, and I feel I have one now that is built right.  I did use an old PC P/S case from eBay.  The build was tight, but I like the extra ventilation slots, lol.  I would get one of those aluminum boxes for more room to work in if had a redo.  Besides, I waited a good 20 days for the main components to cross the ocean for the cheapest quality build cost.  I did get the on/off switch and terminal strips and fuse holders from Walmart online because of best pricing.  The completed build was around $100 in cost, but I already had the cords, plugs, terminal connectors and tools.  It is fairly easy to build now that I have built one but was not for the first time build when safety is primary.  My second build would go much quicker of course.