I did a test today with my Lee Pro 4-20. I'm new to all this and fascinated. The pyrometer's new too, I highly recommend it so far. it can be had at auberins.com here's the info:High temperature thermometer, Pyrometer (THS-192) Sensor Type Option 10" (250mm) Inconel Probe = $52.98 + shipping. Anyway, it's nice because it reads to .1 degreeF from -199 up to +1000F and then reads in 1.0 degreeF from 1k to 2k degrees. (You can get a ceramic thermocouple that will read to I think 2,300F) so, at setting "5" on the Lee pro, the reading was 1,075F. The lowest setting gave me 745F! I even dunked an ingot in it to make sure I wasn't just experiencing residual heat and it still hovered at 750ish after waiting for 15 minutes! I could probably melt aluminum in this puppy! If I had the time and money to waste, I'd give it a try, but I might ruin the machine and it's the only one I have. Still no exact ID of the grey&brown crust powdery stuff. Does anybody know if it could be lead oxide? Does lead oxidize faster when it gets hotter? Does it get crusty like that?