Using Lee Production Pots
By: Shawn Carnahan
May 08, 2007
Pouring plastic with pots can be effectively accomplished, providing one simple rule is followed:
The user must control the heat in each pot to keep the plastic at the correct temperature without over-heating.
To accomplish this, the user must understand how the pot works and what accessories are needed for proper monitoring.
How the Pot Works
Production pots are heated using a heating coil similar to an electric stove element. This coil is located inside the casing of the pot, about one inch from the bottom. Power to the heating coil is controlled by a thermostatic switch which is located in the case behind the pot, and attached to a user control switch.
A common misconception is that the thermostat switch adjusts the power level ( and thus the heat ) supplied to the heating coil. It does not. It simply turns full power on or off to the coil. The control knob on top of the thermostat is used to find the point at which electrical contact is made to supply full power to the coil. The numerical level of the knob for electrical contact can vary from pot to pot.
The thermostat senses the radiant heat of the pot and opens or closes the electrical contacts depending on this radiant heat. This is important to understand if the pots are located in a very cold or hot location, as the surrounding air temperature can affect the temperature being sensed by the thermostat, and cause power to be supplied or turned off at incorrect pot temperatures. Having wind or a fan blowing directly on the pots can also affect thermostat operation.
The biggest problem facing the user is that he has no way to tell when full power to the heating coil is on or off. Thus, he is always in danger of over-heating the plastic and burning it.
With this in mind, I have developed several accessories and procedures to help keep plastic at the correct pouring temperature.
Temperature Control Accessories
Thermostat Power Light
Adding a light to the thermostat power wire will enable the user to always tell whether the pots heat coil is on or off. The electrical wiring in the pot is very simple and can be seen by removing the cover plate the thermostat switch is mounted on. ( four ¼ hex-head screws )
I use a small 1 round night light with flat face for the thermostat light. These night lights can be found a Lowes. While at the store, also purchase four wire connectors ( per pot ) similar to the ones you will see attaching the wires to the heating coil, some electrical wire and superglue.
Cut two 5 wires and attach one to each prong on the night light using the new wire connectors. Now, pull the wire connector leading from the thermostat to the heat coil ( at the thermostat side ), clip the connector off and attach a new connector which contains the original wire and one of the wires attached to the light. Re-attach the connector to the thermostat. Be very careful, the thermostat is fragile.
Next, pull the power cord wire which attaches directly to the other side of the heating coil. Clip the connector off and attach a new connector containing the power cord wire and the remaining wire from the light. Re-attach the connector to the heat coil.
Drill a 3/8 hole in the thermostat cover plate, centered and about ¾ from the existing mounting plate screw hole on the right side of the cover plate. Now, using superglue, attach the flat top side of the light to the underside of the cover plate over the hole you drilled, making sure it does not extend close to the cover plate edge where it might interfere with re-assembly. Once dry, re-assemble the cover plate, making sure none of the internal wires touch the thermostat or heating coil. If done correctly, the light will be on anytime power to the heat coil is on.
Thermometers must be used in each pot to monitor the actual heat of the plastic. Candy thermometers with a temperature range up to 400 degrees can be purchased at most local grocery stores.
To get accurate readings, the thermometer should be suspended in the pot without touching the sides or bottom. I accomplish this by attaching a holder to each pot.
Get a heavy gauge paper-clip and straighten it out. Bend a small loop at one end and then bend the loop 90 degrees from the straight wire. Attach the loop to the top of the pot with the paperclip wire pointing straight up, by removing one of the ¼ hex head screws holding down the weighted pouring bar. Now, bend the top of the wire down past 90 degrees towards the pot at a height that will allow your thermometer to hang in the pot , just out of contact with the side and bottom. Bend the last ¼ of the wire back upward to hold the thermometer in place.
With the light and thermometer in place, you will have very precise control over the heat of your plastic.
Here are some other tips to successful production pot use.
Use a small diameter, 8 long wooden dowel in each pot to keep your plastic stirred. Do not use the glass thermometer for stirring unless you like glass in your worms. Plastic should be stirred every few minutes throughout the initial heating process, and between each mold pouring to ensure uniform color and flake mixtures.
Pots should be kept filled above the level that the heating element is located to ensure uniform heating. I keep at least half the pot full when possible. As you start to empty out a pot during pouring, you will need to monitor the heat more closely.
All plastics will begin to burn if they reach a sustained heat of over 375 degrees for more than a few minutes.
CPC Plastic pours best at a sustained temperature of 340 - 350 degrees.
LureCraft and MF Plastic pours best at a sustained temperature of 330 - 340 degrees.
Make sure you pour in an area with good ventilation. Heated plastic is not good to breathe. I have a range hood with an exhaust fan above my pots in the garage with a vent pipe leading outside. I also use several box fans to keep air circulating, and I wear a dust mask.
Do not pour indoors. The plastic smell permeates, and your non-fishing friends will not understand.
To clean pots after use, allow the remaining plastic to cure completely. Remove the two screws holding the pouring bar on and set aside the bar and plunger. The plastic can usually be removed in one piece and stored for re-use when that color is needed again. Wipe out the inside of the pot with a paper towel and re-install the plunger and pouring bar. A small amount of WD-40 sprayed into the pot will keep it from rusting and also add some natural fish oil scent to your next pouring project.