Electronic temp control

[Bret4207]

Someone recently mentioned adding an electronic temp controller to their Lee pot. Any idea where I'd find something like that? I just got an old SAECO and it doesn't shut off.

[Bret4207]

Found it- a PID. Why couldn't I remember that?

[mikenbarb]

Got a link to it? I need one also for a Saeco that has the same problemLOL.

[revolver junkie]

midway sells replacements for lees

[Bret4207]

Got a link to it? I need one also for a Saeco that has the same problemLOL.

http://castboolits.gunloads.com/showthread.php?t=45733

[Charlie]

I was fed up with the rotten temperature control on my old Lee Production pot so I converted it to a PID controller. I used the controller and thermocouple from the company at the link below. The controller is simple to set up, automatically programs and has an internal relay good for 10A @120V to control the heater. Now I can set the desired temp and get a read out of the actual lead temp in the pot. It holds the temp to within about 10 deg of the setting.

I temporarily wired it to try it out. The upper display is the actual temp from the thermcouple. The lower is the set temp, 700 deg in this case. The lower display is green which does not show up well in the photo.


This is the finished pot with the PID controller in a case attached to the back of the pot.


The PID & termocouple cost $60 including shipping

[URL="http://auberins.com/index.php?main_page=product_info&cPath=1&products_ id=1&zenid=50084f9fcd19cecc0936d8b31a5f18c5"]

[cheese1566]

I tried the link, but it goes doesn't work... which PID did you use?

I don't see one on the website with a 10amp output without a relay... I have no experience with PID's so simplicity is best.

Nevermind, I just found it..."1/16 DIN PID Temperature Controller (Relay Output)$44.50"

Which thermocouple did you use?

I think I need an idiot's guide to setting one of these up. Can I get list of what was used and how it is set up. I have a Lee 4-20 production pot.

[RP]

I got a ? I just junked out a stove robbed the burners and controls for them. I was going to use them in a new casting pot. Useing my Lyman ther. to check the heat then mark the control for future referance. Once set to temp it should keep it at that temp? or is it the longer it sits warming or while using the lead gets hotter and hotter. I know the lead will cool off when adding new lead to the mix.

[briang]

From what I've heard as you take lead out it will get hotter, never checked myself.

[No_1]

[QUOTE=cheese1566;532637]Which thermocouple did you use?[QUOTE]

I am curious also since I do not see the thermocouple in your pics.

Robert

[Echo]

I got a ? I just junked out a stove robbed the burners and controls for them. I was going to use them in a new casting pot. Useing my Lyman ther. to check the heat then mark the control for future referance. Once set to temp it should keep it at that temp? or is it the longer it sits warming or while using the lead gets hotter and hotter. I know the lead will cool off when adding new lead to the mix.

Right. The controls on most of our furnaces are Power controls, not Temperature controls. In other words, they are not thermostats, so they are controlling a set amount of power going to the element. Less lead, less heat lost, higher temperature. I understand the RCBS 20-pounder uses an actual thermostat control.

[Charlie]

Just about any of the K thermocouples will work. They are all high temperature insulation good for at least 900 deg. The outer sheath is typically stainless steel which is good to a higher temperature than the carbon steel of the Lee pot. I welded a 1/4 20 nut to the bottom of the pot & screwed the Model: TC-K6 thermocouple in it. You can see the lead in the picture.



If you don't want to weld then just get one of the probe type TCs like Model: WRNK-171S & put it in the lead from the top of the pot. You will need to make a bracket out of wire or the like to keep it submerged in the lead.

The Aubner web site has the manuals for the controllers on line. Download one & they show sample wiring diagrams on pg 12. They show all the extra features it can do like actuate alarms but the only connections needed are power to the PID controller, the 2 wire connection for the TC(make sure you get the polarity right) and wire the PID internal relay in place of the thermostat in the pot. The terminals on the PID are all marked as to their function. Here is a wiring diagram for the numbered terminals on the back of the PID. The fuses are optional, I didn't use any.



The PID is set up with default parameters for K type TCs & an avg control. It worked great for me with the factory settings. If you want to get fancy, the instructions show you how to turn the learn mode feature on so that the PID will cycle on & off about 3 times while it watches the temperature response of the pot. It will set the parameters for the best operation based on that. It is very simple.

BTW, Here is the original thermostat for the Lee Production Pot. As you can see it is not really a true thermostat, it does not read the temp of the lead. It is a timer, it cycles on & off with the heating of a bimetalic strip. This is the part I took out & replaced with the PID.

[Wayne S]

[QUOTE=Echo;533385. I understand the RCBS 20-pounder uses an actual thermostat control.[/QUOTE]
Does anyone know for a fact WHAT RCBS uses ???

[RP]

Well I guess I was thinking right about the stove controls thats my luck and it was way to easy. Thanks for the imput.

[Willbird]

Any lead pot I have ever seen uses a thermostatic control. It is NOT a rheostat or a "power control"

Where the thermostat is in relation to the pot will determine how accurate it is. Somebody here took apart their promelt and showed the guts.

http://castboolits.gunloads.com/showthread.php?p=522568

Bill

[Echo]

Well - they ARE 'Power' controls. They are not rheostats, of course, but they control the average amount of power going to the heating element They do this be adjusting the duty cycle. Turning the knob higher puts more strain on the bimetal strip, causing it to maintain contact for a higher percentage of time. It is the heat generated by the current going through the bimetal strip that causes it to deform and move. Less stress (knob turned down) means that the contacts are 'made' for less time, therefore power is provided to the element for a lesser pecentage of time. Else how can we explain the control in the Lee shown above, that is completely separate from the heating element? And they do this independently of the temperature of the alloy, so the are not thermostats.

And these are what us old missile-men called 'bang-bang' systems - they are either on or off. A proportional system sends more power to the unit when there is more of a difference between what is desired and what is actual. As the desired condition is neared, the input is reduced until it hits zero when the desired condition is achieved. The thermostat in our house works as a bang-bang system - when the temperature drops a degree below where we have it set, the furnace comes on full bore, and stays that way until the temperature rises to one degree above the setting, in which case the furnace shuts off. Samo with the electric blanket - samo with most control circuits we encounter daily. Seldom is a fully proportional system needed in our daily life.

One example of a proportional system we use every day, or at least dang often is the thermostat in our car's cooling system. When we start the car, and the coolant is 'way cool, the thermostat is closed, so there is no transfer of heat from the engine to the radiator. As the engine warms up, the thermostat slowly opens to allow coolant flow to the radiator, and stays open just enough to keep the coolant at the desired temperature. And if we really flog the car,the thermostat will open wider to allow more flow, allowing more heat to be discharged from the radiator.

And I believe the above electric thermostatically controlled system is probably a bang-bang system, in that it probably controls the temperature by sending full power, or no power, to the element. A probable very positive aspect of the above system is its sensitivity - will probably keep the alloy where you want it, within a very few degrees. Undoubtedly much more sensitive than the bimetal strip controller most of our furnaces use.

As I've said before - I DO go on...

[Willbird]

I may have misspoke about the LEE, if that is how they truly work and radiant heat from the Pot is not somehow having an influence on the bimetal strip then the guy who insist "LEE is just as good at 1/4 the price" are smoking something .

One advantage of the PID is that it uses fuzzy logic to use past performance to try to do a better job next cycle than it did last time.

Bill

[Echo]

Wow. Just googled PID controllers, and I want one! Profound devices that are more than proportional! I have an old Lyman pot that seems to be confused, so will make a controller as shown above. Will probably need some help from forum experts, but Hey...

[thebigmac]

YOU OLD GUYS WITH YOUR ANCIENT SAECO AND LYMAN LEAD POTS NEED TO DO WHAT I DID.
(Plastic Process Equipt. Inc--8303 Corporate Park Dr.---Macedonia, Oh. 44056). IS THE PLACE TO CONTACT FOR A REPLACEMENT THERMOSTAT. I JUST COMPLETED REPLACEING MINE, AND WITH A LITTLE MINOR ENGINEERING(?) MADE IT FIT. WORKS GREAT, JUST LIKE HAVING MY OLD POT BACK. YOU WANT MODEL B-200. SORRY, DON'T HAVE ADDRESS OR WEB, BUT GOOGLE IT.. WORTH A TRY. $23.00 PLUS UPS/// Mac

[jhrosier]

YOU OLD GUYS WITH YOUR ANCIENT SAECO AND LYMAN LEAD POTS...

You been peekin' in my cellar window?

Thanks for the info.

Jack