Melting Lead

[686]

i was melting ww over the weekend. i use 3 pots to make it go faster. these are 40 lb to 80 lb pots. at one point one of the pots was making silver foam looking stuf on top. the other 2 were fine. the lead cane out of the same batch. i did not check the temp. i have let some get to hot to where it turned rusty and blue color, but have not had this before. all pots normaly run 750 de. any help? thanks charles

[runfiverun]

did it go away?
did it flux in ?
my guess is antimony floating on top and would flux in.

[hyoder]

at 750 degrees that may be zinc.
Run your temp just hot enough to get past the thick slurry stage.
That way you can skim off the junk before it melts.
You'll have some painted lead WW's that will take a little longer to melt.
At 750 you've probably got zinc WW's melting.

[686]

i did flux and it did not help. i did skim off and finley went away as i keep puttung in more ww. i think zink takes over 800 to melt. not sure what it was. thanks

[leftiye]

We've gotten several posts on this lately. The official designation for it is CRAP. Some say it is zinc, some say it is Antimony, some think it is ink contamination. Don't suppose you had any ink on your wheelweights did you?? I threw mine out too. Lost 55 lbs out of 100 from type metal. It would stir back in when you got hot enough, but would separate again when it was remelted. Considering that yours, and some of the other's metal was wheelweights, it's not very likely that it is antimony (not enough antimony in wheelweights to separate out, I'd expect). That leaves zinc.