black foam!

[troy_mclure]

im melting some shot down into ingots, at both very high and verry low temps theres black crud, and pellets that stay round and float on top till i crush them. even stirring they dont melt.
but when i add flux, both lard and paraffin the pellets dissolve, and all the black turns to a black foam that will overflow the pot. it rises up like vinegar/baking soda fast. even trying to stir it in doesnt help.

any ideas what it is, i scooped it out into another pan in case its something important.

[odoh]

Graphite perhaps?

[Gar]

Yup, sounds like graphite. I've been working on smelting the 2 tons of reclaimed shot I bought and it does the same thing. Nasty looking stuff.
Be sure to keep it hot, flux it and stir well to keep the antimony mixed in the lead and just skim the crud off.

[schutzen]

Steel Shot? Black Cloud steel shot load can leave a difficult to remove black crud in the barrel.

[leadman]

I have found in melting reclaimed shot it is better to melt a little at a time. That way the pellets melt much faster.
Too many pellets in the pot and the crud and graphite form a thick layer on top of the molten lead causing the pellets to be somewhat insulated from the molten lead.

[XWrench3]

Steel Shot? Black Cloud steel shot load can leave a difficult to remove black crud in the barrel.

if he is getting the stuff in his pot so hot it melts steel, he has way bigger problems than black foam!!!

[schutzen]

I understand steel will not melt in a lead pot, but notice he said "and pellets that stay round and float on top till i crush them. even stirring they dont melt." I have seen a few steel shot pellets that would crush to dust after they had been fired into a hard object.