uzaymaymunu - 3-3-2013 at 09:22
http://youtu.be/6ymQU3ZOrF0
As the oxide layer forming on the surface of the hot molten lead thickens the metals colour changes. (used air gun lead)
I have tried with fishing lead but it did not form a "rainbow" 
Fantasma4500 - 9-3-2013 at 17:02
strange.. never seen anything like this before.. ive melted quite abit of lead, tho..
guess this isnt under normal conditions (~20% oxygen)