Zink bad?

[tew45]

Why is zink bad for cast bullets? I'm sure that over the years I have had some zink in my cast bullets even after efforts to remove it.

[William Yanda]

From my reading, mostly here, excessive zinc makes casting boolits difficult. Minor amounts may not induce the same difficulty. In fact, some casters deliberately add copper to modify alloys. Whether or not it is relevant, copper and zinc are close to each other in the periodic table.

[smithnframe]

I cast and handload a Harvey Protex bore bullet with a zinc washer attached to it.

[bangerjim]

There is another thread currently active on here that discusses Zn contamination.

I have thoroughly tested 1 to 5% contamination in past years and found absolutely no degradation in performance. Above that you will lighten your boolits and the mix will become harder to fill the mold. Just add more Sn to decrease the surface tension and you are good to cast nice boolits.

Check out that thread about "scientifically analyzing Zn in a mix" currently very active!

Just examine all you feed stock for your re-melting pot to insure you do not get zinkers in there. If you miss one or two, it will not make nay difference. Also keep your melt temps on the low end so zinkers will float on the top or be easily skimmed.


banger

[Land Owner]

Some casters discover their melted alloy has the consistency of oatmeal and won't dispense through a bottom pour spout. That's a tell-tale sign of too much zinc. Some casters save their zinc wheel weights and make zinc-only boolits too. The melting points of lead and zinc are "close enough". Most melting pots are capable of greater than 800* F temperature. Cast a little "colder" and the "problem" of melting zinc is reduced.

Melting Point (*F)
Zinc - 787
Lead - 621

[fredj338]

As noted above, some zinc is not a problem. If it wont flow at 700-725 deg or so, then you might have too much zinc contamination in your alloy. I have has this happen before with unkown alloy, so turn the heat up & add more lead. Flux the heck out of it and back to normal.

[Geezer in NH]

I cast and handload a Harvey Protex bore bullet with a zinc washer attached to it.

Screwing up the range lead eh? Small amounts of zinc don't hurt anything IMHO. Just dilute it when it does become one. I just look for shootable bullets. Most hit paper. When it hits game it usually kills it.