Temp control for old bottom pour

[abunaitoo]

I have an old Potters bottom pour. Looks like it was never used. Missing the cord.
I found a cord for it. Plugged it in and it get hot, but there is no temp control on it.
From the pictures in the catalog, it looks like the temp control was in line with the plug.
Would a LEE temp control work?????
I would probably make a box and just wire it inline.

[dikman]

As far as I know the Lee relies on picking up temperature changes from the pot assembly, so wouldn't work too well if wired inline. I reckon the best thing would be to buy/make a PID control for something like that.

[odinohi]

I heard you can wire up a dimmer switch to work as a crude temp control.

[JASON4X4]

Install a pid and never look back

[tja6435]

Cheap pid setup is ideal for your situation
104621

[bangerjim]

Nothing inline will sense the temp! As said the Lee it a bi-metalic thermostat inside the housing that senses the temp.

I am not a fan of PID-based temperature controllers on little lead pots but you could go that route if you wish to invest the time and money. Or buy a new Lee 4-20.

bangerjim

[dikman]

I wasn't advocating a PID as the be-all-and-end-all of temp. controllers, rather in this particular case it seemed like the logical way to go. Of course, if it looks like you're going to end up spending a bit on it, as Jim said you might as well buy a new Lee pot (they're not that expensive).

[abunaitoo]

This pot was givin to me.
It's to small for me, but I was just wondering if something could be added to make casting easier.
I've read that you would unplug it when the temp got to where it cast good. Then when it cooled to where it started to cast "not so good", you plugged it back in.
I'll probably try the dimmer switch.

[mold maker]

Non of the light dimmer switches, I've ever seen, will handle the wattage of a furnace. Most dimmers are rated at 300 W or less. Most pots are 700-1000 W.
They do however work great on a lube/sizer heater.

[el34]

I hated the inability of the Lee 4-20 to maintain temp. The bimetallic strip has no idea how hot the lead is and therefore can't regulate it. What the strip does is set the ontime duty cycle- what % of the time it's on to what % of the time it's off. Others have called it a 'power control' but not a temp control. A light dimmer would do exactly the same thing.

That is like setting your car's accelerator at just one spot and expecting it to maintain a constant speed even when going up or downhill or through wind changes. Or if your home's heater was controlled by setting how many minutes to run it followed by how many minutes to wait before running it again, all with no awareness of the temp in your house (open-loop system).

When casting, the fullness of the pot and the addition of new ingots and the return of sprues all affect how often the heater needs to be on and for how long if a regulated temp is desired.

That begs the question- why do I care about maintaining a constant pot temp? The answer is rooted in the ability of a mold to repeatedly and simply make good boolits- temp is an important aspect. Mold temp is another, someday we'll figger out how to automatically regulate that too.

PID control does a magnificent job because it's a thermostat and knows if it needs to do more or less of what it's there to do based on knowing if its target is above or below what it should be (closed-loop system). It can then compensate for any variables affecting temp.

[blikseme300]

I heard you can wire up a dimmer switch to work as a crude temp control.

Unless the dimmer is rated to handle the current draw you will need a can of smoke to refill it from time-to-time as electrical circuits work on smoke. Once it comes out it no longer works. [smilie=l:

[abunaitoo]

I've wondered about if the dimmer would handle the watts. Seems like a bulb draws way less than the heater.
What about an electric stove burner control????
Most are for 220v, but might it work????
Control from a portable hot plate????
Looking for the cheapest way to go.

[el34]

Get a 200-1000deg thermometer and a power strip that has a switch. Plug the pot into the strip and turn it on. When the thermometer says 800deg turn the switch off until the thermometer gets to 750 then turn it back on again.

Human thermostat.

[theperfessor]

PID - let me repeat that - PID

Much better than ANY thermostat/dimmer switch/plug and unplug control system.

They are relatively cheap, will give the superior temperature control, and can be used on different units.

Having one makes a tremendous difference in my casting quality and enjoyment.

[jsizemore]

Lutron sells a 1000 watt dimmer but they ain't cheap. For what you spend on it you could have gone the pid route and been happier. Setup as a control box you could use it as a plug and go controller for various chores.

[el34]

Get a 200-1000deg thermometer and a power strip that has a switch. Plug the pot into the strip and turn it on. When the thermometer says 800deg turn the switch off until the thermometer gets to 750 then turn it back on again.

Human thermostat.


PID - let me repeat that - PID

Much better than ANY thermostat/dimmer switch/plug and unplug control system.
They are relatively cheap, will give the superior temperature control, and can be used on different units.
Having one makes a tremendous difference in my casting quality and enjoyment.

Yep.
While using the human thermostat method, take note of how fast the pot heats up and how far the temp keeps rising after turning it off. Then use those observations to better know when to predictively flip the switch.

Human PID.