Zinc Contamination

[Ed Gallop]

I was offered an abundance of pure zinc sheets by someone I reload for. I know one problem is contamination of lead when casting but do not know what the contamination consist of? Also... I learned pure zinc fired through a barrel will clean out leading but will zinc fouling exist and be even harder to clean out?

[qajaq59]

The zinc contamination will generally make it hard to get good fill-in with the molds. I never heard that it would zinc up your barrel though. However, I do know there's a couple of people in here that do use lead with a little zinc in it for casting, so hopefully they will comment?

[sagacious]

Zinc 'fouling' would be the easiest fouling to remove... if it were even a problem. Not likely to be a problem. Are you even going to use the zinc for casting?

Casting pure zinc is different than casting lead. Higher temp and more consistent mold temp are required, etc. Do not mix it with your lead unless you want to wade through difficulties far greater than bore fouling.

[docone31]

Zinc is simple.
I mix lead with my zinc. It gives me an hard casting. A little lighter, but does it well.
Because zinc is harder than lead, and I use Lee molds, I run them hot, and count six to desprue. Longer, and the sprue is difficult, less time and I do not get good fillout.
I started by accidently getting zinc in the melt. People told me to toss the melt, use sulphur, muriatic acid, so on and so on. I decided to try it. I had nothing to lose.
I cut the melt lots with roof lead. I get it from a contractor. Once I got the melt light in zinc per pot, I started experimenting.
I figuire I am an easy 2% zinc in my pistol castings. No leading at all, no tumbleing, no excess pressure. I use the data for the mold size, rather than the actual weight.
I water drop the castings, and size right away. I pan lube.
I figuire, with all the lead issues, zinc is going to be the only way to go.
It works. I melt all my wheel weights, keeping count on the zinc/lead ratios. You can tell, once you get used to it.
I use Kitty Litter for flux.
You gotta run it hot for zinc. Gotta heat the mold, melt, and just get used to it. Many thousands of rounds now, lots in rifles also, they can go hot. I paper patch the zinc castings for them, and have run them in just zinc castings. The zinc castings do tumble, the paper patches do not.
I like this. The bores do not take much cleaning effort, I get lots of reloads from my brass, and I can still get wheel weights. They may be zinc, but with the slower powders, zinc is ok.

[Le Loup Solitaire]

There is an article in the NRA Reloading Handbook that describes bullet performance with bullets cast out of zinc. They are very hard and bullets fired into a wooden log were recovered undeformed up to ten times, reloaded and fired again. No mention was made of fouling, but if there was a problem it would have been noted. Zinc otherwise is a real pain in the butt if there is any amount present in a casting alloy. It usually gets into the mix via wheelweights and can really mess up a pot of metal; ruins the fillout properties creating sunken spots and incomplete bands. Until removed or diluted enough it can drive one nuts. It takes a lot of patience and work to get rid of it and get decent bullets. LLS

[lwknight]

If you get a lot of zinc , it will make an oatmeal like sludge on top of the melt. Skim it off and toss in in your zinc pile. Zinc scrap is worth more than lead right now.
It takes only a little zinc to make lead very hard. It will start out soft but within a few days will be brittle hard.
You can cast with zinc contaminated lead but, personally , I do not want to deal with it.

[Ed Gallop]

Exactly what I was looking for. Lots of knowledgeable casters here. Thanks.

[DLCTEX]

I'd trade the zinc for WW or sell it and buy good alloy.

[shootinxd]

Has anybody got some zinc pics.I think I might have a zinc contamination in my pot.Had one heck of a time saturday trying to cast some 40cal.

[DukeInFlorida]

WW alloy has an "oatmeal" stage, just before it liquefies.

If you were casting WW alloy, and had constant oatmeal, your heat wasn't high enough. That's why most people get a thermometer. Then you know where you really are.

[lwknight]

The zinc oatmeal piles high and will not go away. its very floaty.

[pjh421]

I was processing some WW the other day and had about 1/4" of melt in the bottom of the dutch oven. A friend had given me an ingot of mystery metal that weighed about 40-50 pounds. I set it in the pot and though it melted at ~680F it poured out into the 10 pound moulds in a rather lumpy fashion. Also there was what appeared to be a clear liquid on top of the melt. This ingot had some WW in it obviously but I'm not letting it get mixed in with my boolit alloy. I was thinking I would let it sit until I build a lead wire extruder and buy some H-dies. A-neat's swage press project has me jonesing for a big press. Gotta finish my AR-10 project first. Sorry for drifting.

Paul