Sorry if this is obvious for you guys, I´ve tried seaching and stickies for this, but are getting crosseyed trying to read it all and come to a conclusion.. so therefore I put my own Q´s here.
Got a batch of unknown lead today from a friend.. he had got from someone else, so there is no way to tell the source of this.. as usual! (The original donor had used it for casting fishing sinkers. The lead was poured into old cans in different layers, some harder then others..)
Throw it in my smelting pot and heated it up on the propane stove.. unfortunally I got distracted by a phonecall while it heated up..
I didn´t had a thermometer handy either.. (that one is stuck in my casting pot!) but the smelt seemed to be pretty hot when I returned.
I fluxed the smelt with sawdust and candlewax.. I had a thick metallic crud floating on top that wouldnt melt so I skimmed that off.
My first thought was thats Zink?
#Does a small amount of already molten zink in a contaminated batch float on top, (if temp is at par with lead but below zink) of an otherwise liquid melt when re-melting, or does it turn the whole melt into oatmeal?
After getting the course crud out the surface of the smelt quickly turned golden/purple/blue.. also formed a skin on top (like skin on warm milk) Fluxed once more and could skim alot more gunk out, then surface quickly took to nice oily colours again, with the same skin on top.
I poured my ingots and they took quite a while to turn solid..
# Was the smelt temp to high?/ to low?
# Was the crud I skimmed of good stuff (tin and such?)
#Would it be a good idea to remelt this batch, return the gunk, flux it some more, and try to do it all over again at a more controlled temp?
Pic of one casted ingot:
Pic of smelting pot with the colourful skin on top:
Thank you..
Per