More Wheel Weight Questions

[Vacek]

OK. I started sorting through my free 5 gallon bucket of wheel weights I got from the local farm coop. I want to make sure that I don't contaminate them with the zinc weights.

Some of the weights have a paint coating, others are shiny (not oxidized). Regardless, there is often informaiton on the weights indicating weight in ounces and/or grams. But the big question...Are the zinc weights indicated to be zinc in any way or is this just a by-guessby-golly proposition. If it is a by-guess-by-golly then how much zinc can be accidently melted into the lead without creating huge issues?

 

[Rottweiler]

pick through them and anything that is suspect of being zinc....try to cut it with a pair of wire cutters(dykes) lead will cut fairly easy zinc won't . Another way is to drop them on concrete. The lead ones will make a thud. a zinc one will make more of a metallic clank

 

[par0thead151]

what will zinc do if it melts with the lead?
can it be skimmed out like the other contaminants?

 

[Wiljen]

Some zinc weights are marked Zn on them -others not, so it is hard to isolate all of them. The sound test mentioned helps as steel and zinc ring when dropped, lead just makes a thud. The surest way to get rid of all the garbage (Zinc,steel,valve stems, etc...) is to melt your mix below 787F (the melting point of zinc) and skim off everything that floats. It used to be that I rarely saw steel or zinc weights, now I'm getting a lot of steel stick ons, and a handful of zinc clip-ons in every batch it seems.


Even 1 WW worth of zinc melted in with your lead will ruin the batch. It makes getting decent fill-out impossible. So it is worth the time to take it slow and make sure you get them out.

 

[HRT]

From my limited experience just a little zinc will make the whole pot uncastable for bullets. Mold won't fill out etc.

 

[par0thead151]

hmmm... good to know this ahead of time.
what is the melting temp of lead? google shows 621 Fahrenheit.
sorry im new to this, and trying to avoid any pitfalls that would contaminate quality lead.

 

[snuffy]

Any amount of zinc will contaminate lead making it unusable for casting boolits. That means one zinc wheelweight in 10 pounds of lead will make it unusable. It cannot be skimmed off, or removed by any other means. The lead will have the consistency of oatmeal, it refuses to flow easily.

The zinc wheelweights sometimes have a marking of ZN on them. Best way to keep them out of the melt is temperature control. Zinc melts at 787ºF. So smelting lead wheelweights below that temp allows you to see them floating on top of the melt so they can be removed.

Take a look at this thread over on cast boolits .com. Zinc is being discussed there, one fella even says it can be skimmed of while melted!

http://castboolits.gunloads.com/showthread.php?t=20800&highlight=zinc+wheelweights

 

[Dave B]

Most, but not all, have the weight riveted to the clip. Look on the back. Paint means nothing. I skim the clips and junk out as soon as possible. If some are still floating at this point, skim them out too. Be suspicious of the floaters. I tap them on a piece of iron and they do have more of a "clink" than a "thud".

 

[rcmodel]

Another rough rule of thumb is:
If it's shiny, toss it!

Real lead alloy wheel-weights quickly oxidize to that familiar dull-grey color.
And finding one of the old clip-on weights painted would be pretty unusual.

rcmodel

 

[fireflyfather]

I don't use a thermometer, but I have never gotten zinc into my melt. Anything that is bolted it out during sorting. You will learn to recognize the common zinc shapes during sorting also. Any other that get by you will float for a good while before melting, when other stuff is already melted. That's your clue. When in doubt while smelting, toss it. Is 1 or 2 bullets worth of potential lead worth ruining a pot full? No.

If you're unsure while sorting, tap it on concrete or iron. Also, try cutting or bending (for stick-ons) lead will bend. Zinc will snap. Many perfectly good lead clip-on weights have a painted, blue/grey film over them, which burns off to reveal good lead underneath. Bet option? Sort, melt, skim, and in that order.