I use the Lyman thermometer. It is built very well and holds up to LONG casting/smelting sessions. Where there is molten lead, you will find my thermometer in it. When smelting I use it to keep my alloy under 700* to avoid melting the zinc WWs into the alloy (even though zinc melts at like 780*-ish....I play it safe and never go over 700*). When casting you will find a consistent alloy temp will produce consistent bullets.
~NRA LIFE MEMBER~
~NRA CERTIFIED INSTRUCTOR~