Wheel weights: lead vs zinc

[Grizzle_Bear]

Just got gifted a large box of mixed wheel weights.  Didn't weigh the box, but it takes a serious grunt to pick up!  I had read somewhere that the newer stick-on weights were all zinc.  Doesn't look that way to me.  Even some of the clip-on weights are almost certainly zinc, as they are way harder than lead.  But it is difficult to tell with a lot of these things.

Is there any simple, fairly foolproof way to sort the lead weights from the zinc ones?

While some of the lead ones are soft, some that I am sure are lead have been hardened to the point they seem nearly as hard as the zinc ones.  I am pretty ignorant of chemistry, but I wonder if there might be some sort of chemical that would react with one metal but not the other?  I could try a specific-gravity test, but first I would have to remove the steel clips from all of them.  Also, having to check any questionable ones, one-at-a-time, would waste even more time than an old retired guy like me has left!

I am still researching, but any suggestions would be greatly appreciated.

Rob
widely known as
Grizzle Bear

[Solus]

Maybe the quickest way is to melt them.

Lead will melt at about 621F  and Zinc at 787.

What you will need to do is heat some "for sure" lead slowly measuring temp with the proper thermometer.

Hold the temp there..should be near the 621 mark or allow it to get near 700 for faster melting.

Add a relatively small amount (compared to the current puddle size) so it does  not cause to much of a temp change.  Lead will melt into the puddle while zinc and any steel will float.  Pluck the floaters out...don't use your fingers =)

Zinc is not bad to have.  In the proper mix, it will allow some hard cast lead bullets

[Grizzle_Bear]

Howdy, Solus!

I have seen several cautions about NOT getting any zinc melted into your lead.  Seems to make the resulting alloy very reluctant to properly fill out your mould.  All the warnings about this are why I feel the need to separate the two metals.

Rob

[GASPASSERDELUXE]

Go to castboolits.gunloads.com. These guys are the experts  with lead however SOLUS was correct with his advice. You do not want any zinc in your melt when casting bullets.

[Solus]

Not a metallurgist, but if the temp is pretty far below the melting point of zinc, we might be talking some molecules if anything.  That is why  you go slow and control the temp...so nothing can melt but the lead.

The only other way I would know of is by specific gravity. 

Archimedes worked this one out. 

A known weight of lead will displace a known volume of water.  Zinc and Steel will displace less.

So, if you weigh a selection of the weights, look up the amount of water to be displaced then lower the weights into water, the high water mark will be raised by the amount of displaced water.  If it is more, you don't have pure lead in your selection.   

If it is less, you have something heavier than lead and those things might not be good to be playing with..and might be worth some cash.

I'm guessing there might be some chemical test for lead/zinc, but I am not aware of it..and it might be pretty spotty....will it detect an alloy?

[Sponsor]

[TAB]

Easy, take a pair of wire cutters,  the zinc will be rock hard, the lead will cut

[MikeBjerum]

I am getting ready to start casting my own for SASS.  I have talked to several people who have been casting for anywhere from one to 20 years.  They all say to just throw it all in the pot at a temperature of around or just over 700.  The lead will melt, and the then you can pick out the zinc weights and steel clips.  These are people who are casting thousands of bullets per year.  I think they can be trusted.

[Grizzle_Bear]

Thanks to all for your replies.  I found exactly what I wanted on another board.  It seems that commonly available muriatic acid reacts vigorously with zinc, and not at all with lead.

After sorting through all the weights, I actually had very few zinc ones.  There were quite a few of the ones marked "Fe" which are iron (steel).  Most of the zinc ones are marked "Zn", but not all, so some testing was still required.  A lot of the lead ones are marked "P", which makes it easy.  Again, not all of them.

Also had several old battery terminals, most of which were lead, but there was a zinc one in there just to try and trip me up.

"Kids, don't try this at home!"

I still need to run to the pharmacy and get an eye dropper for the acid.  Tried just pouring some in a small plastic dish, but it's not a good idea to just dunk the suspect weight.  Not only does the acid sit there and SMOKE on a humid day, but the stink is a mixture of rotten eggs and Clorox bleach.  You really want to use a minimum amount of the acid!

Thanks again!  The Internet is a wonderful thing!

Grizzle Bear

[tombogan03884]

It's watered down Sulfuric acid, about 20%/80%.
They use it for cleaning masonry.