lee bottom pour rheostat

larry7293

New Member
Does the Lee rheostat turn the heating element on and off when the dial is set at a given number or does the heating element stay on all the time?
 

Dusty Bannister

Well-Known Member
I believe it is a bi-metalic thermostat. The metal strip heats up, opens the contact, shuts off the flow of current, and after a period of time closes and allows the current to flow. Affected by ambient air temperature. As the level of the alloy in the crucible gets lower (less mass to heat) the thermostat does not make that adjustment so the temperature of the melt rises. By moving the knob to a different setting, the tension on the spring is increased runs hotter, or decreases and runs cooler. The knob pointer is a reference and can not be relied upon as a temperature indicator.

Feel free to correct anything I may have not stated correctly. Dusty
 

fiver

Well-Known Member
I think Dusty covered it pretty well.
if your having an issue you can clean the contact points, or bend the strip slightly to make an adjustment.
it doesn't take much.
my pot barely went over 600 when I first got it, a ''small'' adjustment later and I was fighting it at 900... minimum.
a little more effort and it maxes out close to 800 on 10 and is about 700+- around 7.1 or so.
close enough for me to judge around that 700 range where I usually cast at.
 
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Petrol & Powder

Well-Known Member
Dusty hit the nail on the head.

Simple thermostats that rely on bimetallic elements get a lot of criticism but in reality, they work fairly well.
However, because they are a bit slow to react, they maintain more of a range of temperature rather than a point. When you add some other factors, such as the changing amount of mass to control (decreasing amount of lead in the pot) and the addition of large amounts of cooler mass (adding lead to the pot); that range can get bigger.

Simple thermostats work very well when there are limited variables to deal with. For example, a residential tank type water heater does an acceptable job of maintaining water temp in the tank when it's just in stand by. The tank is insulated and there's no influx of cold water. occasionally the water temperature will drop below the set point and the elements will be energized (or the burner activated) until the thermostat opens back up.
When you draw hot water from the tank and cold water rushes in to replace that hot water, the thermostat reacts the same way but there's now a new variable to deal with (the influx of cold water). Because the thermostat is "dumb", it can only react to the temperature it sees. It doesn't know the temperature of the incoming water, the volume of the incoming water or the length of time the cold water will continue to rush in. It only knows if the temperature of the water it is sensing and acts accordingly.
In today's world where it seems like everything is controlled with the assistance of computer, a simple thermostat may look a little outdated. However, in reality, it doesn't need to be very "smart".
 

Ian

Notorious member
I like mechanical things. They wear out but spares and repairs can keep the appliance going. I still have my Snap-On diamond points files for a reason.
 

JWFilips

Well-Known Member
The lee pot Rheostat likes to stick based on
humidity! If is sticks in the on position Pull the plug and move it back ant forth about 5 times plug it .....back in
Once it hits 725Deg Turn it back to 5.5 setting it should keep it The but you should hear it click off!
 

RBHarter

West Central AR
I guess I'm one of those fiddler's .
When I got the big 20# dipper Lee pot I knew/had read that settings weren't absolute . So I set it high to fill it stuck a NOE provided thermometer in it and backed it off until I poured good bullets for 3/4 of the pot ......much hotter that generally suggested by about 50° , I suspect tool calibration but rather that fuss I marked it and carried on .
. Once established I used that point at something like 11-12# in the pot and backed down in till I heard/felt the shut-off then up until it turned on again then halved that added 5# waited until it clicked off and checked the numbers . On hot days it sets just under 7 with a little fidgeting for the line as it goes . On cold days it sets closer to 7-3/4 . 80+ to mid 50s . Unfortunately I haven't run it enough in the "swamp" to know just what to expect from it beyond the above .