View Full Version : Is the Lyman Casting Thermometer a POS

January 8, 2010, 10:21 PM
I casted my first bullets tonight using a lee 20 pot and I was having trouble
with the temperature until I threw the thermometer away and just put the pot temp dial on 7 then every thing went well.
The thermometer was reading 900+ with the lee pot dial on 7 so i kept moving the temp down, then the bullets came out bad. I guess I got a bad thermometer.

I may be wrong but since the pot specs say 900 max going over 900 while the pot is adjusted at the number 4 would be impossible.


January 8, 2010, 10:44 PM
Look at the mix when the melt hits its slush zone, where it's part solid part liquid. Lead's melting point is just over 620°F, so pure lead should be in that range and alloys with tin and antimony should be lower. Wheel weights, for example, melt at under 500°F. So, if the thermometer still reads 900 when the metal is hardening, then you definitely have a problem with the thermometer.

Be aware that the numbers on the Lee pots are not very precise. The thermostat is in the box and not tied directly to the pot, and the one I have wanders about 50° up an down no mater where I set it. I finally made my own temperature control for it.

I and others have used those thermometers for years without problems, but there is no guarantee yours wasn't dropped or something. Conventional thermometers are not typically rugged, so they have to be handled with care.

I use electronic thermocouple thermometers these days. They are less delicate. I got some on sale on closeout for $20 one time that work fine for casting (good withing about 5°). More accuracy costs more, but keep your eye out. Make sure the thermocouple itself is rated for the temperature range you need. Types J or K in glass woven insulation are good.

January 8, 2010, 10:45 PM
Me thinks you got a bad thermometer likely. I thought the upper end on the LEE bottom pour was between 750 and 800. I have the 10 pounder.

I also have a LYMAN pot with no dial. That's what I use most of the time. Have only checked it once, long ago. Still casting without measuring. I get more frosty bullets with the LEE than the LYMAN. Too much heat is sometimes a bad thing.

January 8, 2010, 11:30 PM
If the bullets drop frosty & dia. will work they`ll be more consistent than there counter parts!!! Weigh & measure 25 & do the math!!!:cool::cool:

I have a cheapy & it works ,only goes to 750f but it works !!!!

January 10, 2010, 12:53 AM
I dropped my lyman therm about two times. Once on concrete and once on the grass. Still reads correcty when I hit the pot with a laser therm.