What the heck is in my melting pot?

[qkdraw44]

hi all, I purchased some lead cakes and a load of heavy sinkers. when I melt some and flux it I get a large amount of silver color sludge on top , almost like foam. when I skim it and it cools it is much lighter than lead. one of the sinkers even refused to melt at top temp. setting. I have been mixing it with linotype and am coming up with good hard boolits. and some rejects.(shrunk like a cold mold)
does anybody know what kind of **** I am running through my pot mold and guns.
I really miss the wheel weight days. none to be had here.
thanx Lenny

[GhostHawk]

Willing to bet it is zinc.

Keep to keeping it out is presorting it out before the melt. It has a different ring tone and is harder than lead. Also keeping your melt temp a bit lower.

[turtlezx]

zinc ??
been 4 years since the lead ww ban in new york
not worth sorting ww any more

fellow new yorker

[runfiverun]

silver sludge like oatmeal under the surface?
if so that's ZINC.
if it's somewhat foamy and grey it's antimony separating out and you need heat and fluxing to get it back in.

to clean the zinc out you can either cut the alloy with other alloy to get the amount down to a controllable 1.5% or use sulpher to clean out as much as you can then cut it with less other alloy.

[w5pv]

I skim the oatmeal off into a can to use for trotline weights mold boolits out of the rest.

[mold maker]

EPA and some States ordinances are after the fishing sinkers now. Many are made from zinc or steel alloy.
Be sure of what you have before mixing. If in doubt keep it separate. That way if it's a dud it won't mess up other material.

[bangerjim]

Test your carp with HCl - pool acid. If it fizzed, you got Zn. Even a few bubbles forming means you have some in there. Up to 5% Zn will not harm anything. Your boolits will be a bit lighter and you need to add a few % more Sn to lower the surface tension of your casting alloy to get good mold fills.

Don't let the big bad zinc boogey man scare you!!!!!!!!

banger

[RogerDat]

When you go to melt scrap keep the temp under 750* F anything lead should melt at that temp. Zinc and other junk won't melt. Thermometer is a good thing to have. Tel-Tru makes one that has 1000* range and is effective and less expensive than ones from reloading & casting companies.

Numbered dials are not the same as temperature. Plus you may find that the temp shifts higher when pot gets low, and you will be able to tell when you get back up to casting temp after adding more lead.

The fix test banger mentions is a go-to test for elimination of zinc.