Zinc in Lead

S

steve4102

New member
I just purchased a bunch of WW ingots on-line for a pretty good price. I'm new to casting and could use some help.
How can I tell if these have Zinc present? What do I look for when I melt these ingots as far as Zinc and other unwanteds?

Thanks
 
You may not be able to tell if Zinc is present while it is in the ingot form. However, a contaminated (Zinc, Calcium from maintenance free batteries, etc.), will cast a bullet that will fill the mold but as it cools, it will shrink away from the side of the mold and will drop from the mold distorted. The proof is in the casting.
 
put a few drops of Muratic acid(not spelled right I know), or some drain cleaners, they will fizz with zinc but not lead.
How do you feel there is zinc present?
 
I don't really. The guy I bought the ingots from said they were 100% WW. I was just wondering if there was a a way to tell if he happened to melt some Zinc WW into his ingots by mistake.

He has more for sale and told me to give him a call if I liked them and wanted more. Don't want to order more until I know if I like them.

Thanks
 
Ya, there are a lot of good sources of ww and a few that don't bother with temperature or seperating out the bad. I've had nothing but good stuff when I've boughten it. I would say melt a couple lbs of it and watch the temp that it melts at, if it is around 600-650F and all melted without "oatmeal" like slug on top(zinc doesn't melt till 800F so it will kind of seperate out and form a slug ). If it is all melted, other than maybe some normal oxides on top(no thick junk) it should be the good stuff. Cast a few and see if the bullets get all rough and chunky, or smooth(as long as the mold is hot enough or preheated) and well filled out.
 
I normally melt the WW myself. Normally I can separate the zinc WW before melting. If one slips by I just scoop it off with the slag because they float and melt at a higher temperature. Unless the zink has alloyed with something in your lead I think it would separate and could be scooped off the top with the other sludge. When I melt my WW ingots in the casting pot I also add pure lead and flux the mixture to get the hardness I want and scoop off any slag that forms.
 
If the zinc has dissolved and alloyed into the lead, the lead will cast about like oatmeal. You will know. Supposedly the zinc can be removed by fluxing with sulfur (think about that for a minute) but I don't know. That would be really unpleasant to try.
 
I meant to say sludge not slugs, as stated above it would turn into an "oatmeal" you'll know it, there's no mistaking it. Unless the ww were melted at a high temperature the zinc just floats and can be scooped out. Most know this and the risk of it being there is low, but some don't.They usually are those that don't cast themselves.
I have some good scrapyards nearby and I smelt my own now also, I use my thermometer and never get any hotter than 650F, even down to 575F. I can seperate certain brands of ww that have higher pure lead %
because they will not melt until around 630F , so they'll float also,they are not zinc. I now have a couple piles of ingots that are sperated by ww brand( most ww have a stamp or pattern on them so it's easy to sort them out) ,some are older and have higher antimony and tin. Someday I plan to do some testing to see just what the difference really is.
If zinc is mixed in, skimming the oatmeal can get some of it out, how much I don't know( a small % of zinc is usable as bullets) but to get good clean lead requires powdered sulfur mixed in outdoors and downwind. It is doable, but not something I'm interested in. I would just find something else .to cast out of the mixture(heating it high enough to fully melt the zinc).
 
Last edited:
Thanks for the info. Did a little casting 40+ years ago and I am accumulating equipment and lead to start again. Used a Coleman stove, a 10# lead pot, a dipper, and a single cavity 250gn 45 Colt Lee mold, then pan lubed.
I just acquired a Lee bottom pour pot and a couple of two cavity molds. I have about 20# of linotype and 20# of Lyman #2 from back then. Recently acquired some range lead ingots from our club and have been raking the pond dam where I shoot at the farm for range lead.
When the weather cools off and I get things all together I am looking forward to trying again.
 
If you heat the scrap lead too fast, you can have some zinc trapped at the bottom where it melts before the lead on top melts. Don't ask me how I know this.

On an unrelated topic, :rolleyes: I had about 7 pounds of zinc-contaminated lead on my bench, mocking me. I probably should have thrown it out, but I can't throw anything out (you'd think I was raised during The Depression.) So I cast a bunch of silver dollar sized ingots, and I can put one or two of those in a 20# batch of lead without hurting anything. Three would be pushing my luck. I've used up a couple of pounds of the stuff that way.
 
Melt some & pour in a normal manner if there`s more than 2-4% zinc you`ll know trust me !!

The mold will not fill out ,no matter what !!

Keep it all seperate from known good alloy until ya know.
 
Lead weights thud when droped on concrete. Zinc pings. Zinc also melts at a higher temp. If a large group of weights melt down to good liquid state and there are still weights floating those are the zinc ones. Just scoop em out before they melt and your good to go. I do this every time and have had no problems. I don't even try to cull them out anymore.
 
If they are already ingots then use a casting thermometer, if it looks chunky, or soupy at 700 degrees then it more than likely is contaminated with zinc. Also if you are not getting proper fill out no matter what you do chances are it has zinc.
 
You must log in or register to reply here.
Back
Top