zinc????

[rl69]

I have been reading about how to get zinc out of your lead my question is how are you getting it in there??? when I melt clip on wheel weights I don't worry with separating out the zinc I just skim them off with the clips am I running my pot to cold?

[ssnow]

No, you're fine. From my perspective, the best way to avoid zinc contamination, is to insure that you put no zinc in the pot. This is very easy to do, but the downside is that it is time consuming.

If your pot never exceeds the melting temperature of zinc, then obviously the zinc weights will float. Those who do get zinc contamination, have allowed their pot to get too hot, which is easy enough to do, particularly if they do not use a thermometer.

Sometimes even those who are trying to control their temperature can have issues, because the bottom of the pot will be hotter than the top. You can melt a zinc weight on the bottom of the pot while there is still lead weights above it that have not yet melted......They can't float through a pile of lead weights.....so they melt into the alloy.

[stocker1042]

I've found that separating them isn't that difficult. I'm new to this and after about an hour of sorting I was able to figure out what looked like what without much difficulty.

[rl69]

so what temp dose zinc melt at?

[ssnow]

I believe 787.2 is the official answer.....but zinc wheel weights are an alloy also, so the actual number may vary a bit from this. But, it should be close.

[I'll Make Mine]

The problem here is that zinc doesn't have to melt to get up to around 2% dissolved into lead -- because it dissolves, like sugar in water, rather than melting (analogously, like melting the sugar into caramel -- analogy breaks down because sugar changes chemically at this temperature).

Now, that said, as long as the zinc is remaining dissolved in the lead it's just another hardening agent; where people get into trouble (and where the 780º+ F figure comes from) is that if you let the zinc melt, you'll find it quite difficult to separate the undissolved zinc from the lead alloy -- and it'll separate like oil from water (except for that 2% that dissolves). This will give bullets with hard spots, out of balance, varying weight from one to the next, or any combination of these, depending exactly how you cast.

So, yes, it's probably acceptable to put the mixed weights into the pot and skim out the steel and zinc as soon as the lead alloy is melted. You'll lose a little more lead (stuck to the weights you skim out) than you would if you separated first (you still lose some stuck to the clips), but it may save enough time to be worth it. And the 2% zinc that actually dissolves won't hurt anything.