Zinc?

[Slogg76]

First let me say this is an excellent site! I've been casting bullets for almost ten years and I thought I knew a little bit about it until I started reading up on this site. I keep reading about zinc contamination, bad wheel weights, etc. I have always just smelted all the wheel weights I could get and never even knew about awful zinc. I casted thousands of bullets, mostly for cowboy action shooting, and never had any problems. Most of the wheel weights I've encountered were dark gray. However, lately I've been coming across what appears to be painted wheel weights. They feel heavy like lead, but form an oat meal like mush when they start to melt. I thought maybe zinc, but then again the laser cast and cast performance bullets I melted down also formed oat meal mush as well. The only markings on these painted weights are: 1.75 LH 50g. They do not have a "Zn" marked on them nor does any wheel weight I have come across-yet. Any help with the identification would be appreciated.

[R.M.]

Slogg, zinc can be a pain, and we're seeing more and more of them these days, but I don't think it's as big of a problem as some of us let on. Every time a newbie runs into a strange situation, somebody will say"you have Zinc".
As log as you smelt at a temp lower than zinc melts at, you should be fine. I even hear that an alloy with a bit of zinc can produce decent boolits.

[dale clawson]

Some WW are painted for use on aluminum wheels, it keeps the lead from reacting with the aluminum. I haven't found any painted ones that were zinc yet. DALE

[GabbyM]

You may have skimmed a few zinc WW off with the clips and not even noticed them in their.
You'll get oatmeal in your melt before it comes up to full melt temp. That's the valuable antimony.
Zinc melts at a much higher temperature than lead so unless you go inside for dinner and leave the burner full on under your pot you'll get them skimmed off in time.
Stay with your job. Skim the metal clips off as soon as the lead melts free and you'll get the zinc weights with them. Sometimes I toss one back in to see if it's really zinc. They always are. Works better for me to not add to big a pile into the pot at once. I like to use a square nose shovel to add ww to my pot. So I can stand way back in case it splatters.

Someone will chime in with the melting point of zinc. It's well over 700* .

[Slogg76]

Thanks for the quick replies. I feel relieved. I really don't believe I have come into contact with any zinc weights yet. Most of the wheel weights I was using came from a couple junk yards full of old trucks and cars. But after ten years I think I have just about depleted these two sources. I now get as many wheel weights as I want from local garages and that is where I was discovering "different" looking wheel weights. Thanks again for the quick replies!

[ForneyRider]

I dug up some melting points off of Wikipedia.

Antimony - Melting Point 903.78 K (630.63 °C, 1167.13 °F) Sb
Bismuth - Melting Point 544.7 K (271.5 °C, 520.7 °F) Bi
Lead - Melting Point 600.61K (327.46 °C, 621.43 °F) Pb
Tin - Melting Point 505.08 K (231.93 °C, 449.47 °F) Sn
Zinc - Melting Point: 692.68 K (419.53 °C, 787.15 °F) Zn

Babbit - Soft, white metal, an alloy of tin, lead, copper, and antimony, used to reduce friction in bearings, developed by the US inventor Isaac Babbit in 1839.

I am trying to figure out how to separate Zn and whatnot as well. From the above, the Antimony melts at the highest and is preferred to the Zn. I don't have a thermometer yet for my casting hobby, so I have just been scraping the sludge off the top. It be great if I could separate all metals and control the alloy composition. Not sure how to go about it.