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.

[DLCTEX]

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.

[hunter2]

Finding a lot of painted wts. including zn. The painted ones have AL-MC, MICRO, FN 15, 40g, AL, AW, any ideas?

[HammerMTB]

Finding a lot of painted wts. including zn. The painted ones have AL-MC, MICRO, FN 15, 40g, AL, AW, any ideas?

There are good easy clues to use when you sort your WWs. Zinc weights almost always have Zn on them. They will ring when you drop them, unlike a Pb WW that will thud when you drop it.
I keep a pair of side cutters right at hand, and just try to cut the WW if it is in question. A Pb WW will cut- some really easily, but all can be marked with the side cutters. Zn and Fe weights will not cut readily with side cutters. Fe weights will ring as well, and of course you can use a magnet on them. The caution using a magnet is that the steel rim clip in a Pb weight also attracts a magnet.
Keep an eye open. All my stick-on weights used to be pure Pb. Now there are a considerable # that are Zn and Fe.

[Markbo]

I just thought I would help out since most of us (I am guessing) don't use the Kelvin scale for anything:

Antimony - Melting Point 1167.13 °F or 630.63 °C - SB
Bismuth - Melting Point 520.7 °F or 271.5 °C - Bi
Lead - Melting Point 621.43 °F or 327.46 °C - Pb
Tin - Melting Point 449.47 °F or 231.93 °C - Sn
Zinc - Melting Point: 787.15 °F or 419.53 °C - Zn

Maybe someone wants to print that out in a useful format.

p.s. my apologies to any aerospace engineers who find Kelvin the only 'real' scale to use! :p

[Dannix]

Antimony - Melting Point 1167.13°F or 630.63°C - SB
Bismuth - Melting Point 520.7 °F or 271.5 °C - Bi
Lead - Melting Point 621.43 °F or 327.46°C - Pb
Tin - Melting Point 449.47 °F or 231.93°C - Sn
Zinc - Melting Point 787.15 °F or 419.53°C - Zn


Font, Courier New, code tags, then CODE code tags.

[hunter2]

I keep all the painted wts. to be melted at the same time. They are definately different! Have tried a couple of different smelters, with the above they leak. Building up a column all the way to the bottom opening. I give these to my buddy to make fishing lures. Don't know how they would be making bullets ( have not poured my first one yet ) but was wanting to cut down on all the variables I can. The last bucket of ww went about 30% with these and fe.. Anybody know what would make these so different. They look like mush upon first melting...