overheating lead when melting scrap

[minineo]

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?

[gunoholic]

The yellow powder is "litharge," lead monoxide, which on further heating turns to a brown powder called "massicot." Further oxidation gives a red form, called (of course) "red lead."
i read that in a post by "bent ramrod" in a post here- http://castboolits.gunloads.com/show...powder-in-lead
this maybe what it is, i get a little of this yellow powder in my shotmaker from having the gas turned up too high.

[Tate]

The yellow powder is "litharge," lead monoxide, which on further heating turns to a brown powder called "massicot." Further oxidation gives a red form, called (of course) "red lead."
i read that in a post by "bent ramrod" in a post here- http://castboolits.gunloads.com/show...powder-in-lead
this maybe what it is, i get a little of this yellow powder in my shotmaker from having the gas turned up too high.

My area of interest is in aluminium but I reciently needed some fishing weights so I used my simple aluminium forge which runs on coal and gets way too hot (I didn't know better). After little success keeping the fire going in the rain, I cranked up the air supply to max and the coals glowed (I could melt steel at these temps) I walked away from the furnace to pick up a skimmer and heard a noise similar to that of boiling water, confused as the rain had stopped earlier I turned around to see a white plume of smoke suddenly glow bright green. My jaw dropped, after seeing a few green fireballs shoot out I figured the coast was clear. I immediately killed the air and the fire died in shock I looked into my crucible (half expecting to find an alien mother ship ) where the green had darkened and white ash had coated the sides. I took this as a sign that the remaining metal was ready to be cast. As I normally do when making fishing weights i use aluminium cans with an eye and extension in steel sitting in the can. As I poured I noticed it wouldn't collect and poured the rest on the ground after further inspection it melted holes through all of the sides of the can and deposited much of the lead alloy. I probably should mention that the most of the 'lead' I had had tin in it and was post consumer solder that got a second life I also used some leftovers from my old lead and tin electronics parts. I am even more scared of lead than before. Not sure about using lead anymore except for making circut boards, I rarely have uses for it. After washing cleaning it I kept the fireball looks cool. Defiantly oxidizing but for me more like combustion.

[mto7464]

Why are you scared, sound like you just got it way too hot. Do it properly and you have nothing to fear.

[40Super]

I'd rather deal with 650F molten lead than 1375F(?F) molten aluminum. The lead will burn 1/2" less deep into flesh

[bdecker9]

i just had this happen today. the have no idea what i the crust that formed is, but my boolits weighed in 5 grains less after this happened. i was afraid i had cooked out tin and such. but the weight of the boolits says different. this happened when i switched to a 2 banger mold and slowed production way down. the crust on top was glowing red like when you get steel very hot. i dumped this on my pizza box that i use for landing zone for clips and fluxing trash. this yellow crusty stuff ignited the box. i thought that tin and such burned off at a lower temp than lead, am i wrong?

[Echo]

Hmmm - I'm no expert (!), but I suggest trying to remelt the crust, with a healthy dose of sawdust. If what I read here is right, the oxygen will migrate from the lead oxides to the carbon in the sawdust, forming CO2, and you will recover your Pb. Maybe...

[Pakprotector]

With a Lee 20 pounder and only 5 lb in it of 20:1 I turned it to the same setting I had used on a full pot. It got waaay hot I discovered later, and a lot of that yellow stuff came to the top. Only 1 5 lb ingot. I keep it full and temp stays quite consistent.
cheers,
Douglas

[docone31]

Vegetable oil helps also. Add some and it will bring a lot back from being crud.
It helps.