Wheel Weights for casting

Does anyone know of a way to discern old lead wheel weights from the newer zinc ones? I have a friend who has had problems from the zinc ones getting into his ingot batch. He's tried removing top layer from large melting pot while making ingots with no success. They have a tendency of clogging his furnace nozzle.
Jon

Bad problem today with zinc weights. Makes lead act like oatmeal.

Over here there is a thread on using techniques to detect zinc wheel weights.  And there's a technique discussed on how to remove zinc from a melt.  http://castboolits.gunloads.com/showthread.php?62957-A-possible-way-to-remove-zinc-from-molten-lead

Greetings,

One method is to start a melt with known wheel weights. Then add the pieces one at a time and watch for the ones that "float". These are the Zinc weights.

The secret is to keep the melt just at the temperature that the wheel weights melt and well below the melting point of Zinc. Do not tarry, as the Zinc will slowly mix in with the molten mix.

If the melt gets too hot, the Zinc will mix in the the rest of the melt ruining everything.

Search the web. There are folks that are more well versed on this issue and they have the exact temperature needed to perform the task.

You will need an accurate thermometer to monitor the job; or, one of the fancy PID controller kits using a thermocouple. Again, check with an accurate thermometer.

Cheers,

Dave

Thanks guys, I'll pass it on.
Jon

I use a lot of zinc in my business and don't like it when it is contaminated with lead. Lead mixed with the zinc makes a very poor anode. Zinc melts at around 787fh and lead around 621fh. I use a laser hand held temp gauge to keep me from over heating the pot. I mostly melt down used hull zincs or pot anodes so I have never developed a system of separating except the obvious one of never re-melting an anode that didn't work. Long story to explain why I have several of these.
http://www.ebay.com/itm/Raytek-MT6-Non-contact-MiniTemp-Infrared-Thermometer-New-/381276463440?hash=item58c5d92150:g:1UAAAOSw3xJVZ7H4

Look on the side of the wheel weight, most now have the material acronym. ZN for zinc, AL, for aluminum, TN for tin etc.

If you have dialed in your pot to be only as hot as necessary for lead (which you would definitely do to keep from frosting your bullets), no worries about melting zinc.  Just pick them off of the top.  Also a very noticeable difference in cold hardness.  A little practice with a pair of cutters and you can identify zinc (almost no indentation with significant pressure on the handles of the cutters) before they even get in the pot.  The mortality rate in a typical bucket of free wheelweights in my area is now about 50%; getting to be not worth the effort to scrounge anymore.

This is my first post on this site. I am a long time caster. I bought a Colt Trooper 357 Mag back in 1970 and a few days later my father handed me a bullet mold and told me "If you hope to learn to shoot that thing you better learn how to use this". It was some of the best advice I ever received. Unfortunately zinc and steel WW have been forced on us by the environmentalists. Today I presort all my WW before they get near my melting pot. Zinc WW usually have "ZN" molded into them and steel WW usually have "FE" stamped into them. The real test if you are unsure is a pair of wire cutters. Lead based WW will cut with the plyers while the zinc and steel won't. Save your zinc WW in a separate container because technology is being developed to cast bullets from zinc. Don't laugh .....
the tree huggers forced it on us.

Ok next question?
He has approximately 750# of zinc contaminated ingots. Can it be separated?
Thanks
Jon

I would try removing the zinc in small batches. Begin by melting a pot full. Once it heats up add several tablespoons of copper sulfate. Just let sit on top of the melt till it turns from blue to white. This happens when the moisture in the copper sulfate evaporates. Once it turns white work the copper sulfate through the melt by stirring and rubbing against the side of the pot. It works best with a small amount of tin added to the melt. When doing this the copper adheres to the tin and the zinc adheres to the sulfur. The copper sulfate is saturated when it turns a dark grey or black. It will be a powder and should be removed from the pot. Some of what appears to be contamination could be from dirt that hasn't been fluxed out of the melt. Copper sulfate is available at farm supply stores. It is used to control insects. Using the copper sulfate has the advantage of adding copper to the alloy which gives an alloy greater shear strength with higher velocities possible without leading.

Thanks I'll pass it on
Jon

I came into a large quantity awhile back.  I picked out the questionable ones and dropped them on the floor.  The Zinc will  make a clang type noise where the lead ones are quieter.
I also get a large wire cutter and squeeze them in it.  The wheelweights that are lead will gouge  whereas the Zinc will barely be scratched.

Nick10Ring@aol.com

You can also test with a file. The file will dig in on the lead weights but will skid across the zinc weights.
If you keep the temperature reasonable while melting down, the zinc weights (and steel clips) will simply float to the surface.