Pb-Zn COWW Alloy?

[justindad]

I’m starting to wonder if some modern clip-on wheel weights have a small percentage of zinc in them. I schmelt 10# batches and sometimes there just a little bit of oatmeal in there, even when I used tin snips to check every wheel weight. My habit now is to flux with enough Root Kill to clean out about 0.1% of zinc (if it’s there). Sometimes I have to do a second Root Kill flux to clear the oatmeal. Maybe it’s some other impurity, not sure.

[JonB_in_Glencoe]

It could very well be. You should try an experiment like I did, just to get the feel for what a small % of zinc acts like.

https://www.artfulbullet.com/index.php?threads/zinc-in-small-percentage-in-bullet-alloy.589/

[justindad]

Thanks Jon. I made a ~30lb batch of 50:50 COWW:SOWW and melted 0.2% Zn in it once just to see how the alloy would work with copper in it (swapped Zn for Cu via Root Kill)… still need to test those .357 Keith hollow points. I never tried casting while the Zn was in there, because I figured there would be inclusions galore. Maybe some day I’ll cast some Pb-Zn wadcutters.
*
After I was sure I cleaned out all the Zn and I put the ingots on my main pot, I notice a small amount of oatmeal starting to form. I didn’t want to Root Kill it again, so I added 1% Sn just for kicks - smooth as silk after that. My sprue plates even looked velvety compared to the lead without Sn. I wonder if the Sn helps all the other alloying elements or impurities dissolve into the lead better. That was enough to kill my attempt at being cheap by avoiding Sn (is 1% still cheap?).

[popper]

I shot some 165gr with about 1% Zn on purpose in 40sw. Not a problem except they sized small (no springback as NO Sb) and leaded the barrel - also some went sideways. Alloy wasn't the problem. WW are whatever junk metal they find to use.

[JonB_in_Glencoe]

SNIP>>>
I wonder if the Sn helps all the other alloying elements or impurities dissolve into the lead better. That was enough to kill my attempt at being cheap by avoiding Sn (is 1% still cheap?).

I do know that Zinc and Tin have some sort of relationship, but I don't have the knowledge to explain it...and besides antimony and Bismuth, I don't know about any other alloying elements or impurities it might work with?

[lightman]

Me and a buddy melt our years accumulation of lead, mostly wheelweights, once a year and I always send BNE a sample to test. As of now I have never had any reports of zinc in my wheel weight samples.

[dverna]

There are folks experimenting with zinc bullets. I understand why, but if enough folks do it, it will pollute much of the range lead that has become the "go to" source for people trying to save money.

I expect to see a lot more posts about issues as the use of "mystery alloy" increases.

This will impact the newer casters who have not built up a lifetime supply of alloy like some of the old timers have.

[farmbif]

at my years in the scrapyard I would see all sorts of stuff in the pallet size boxes of lead that got shipped off. I'm pretty sure it's quite expensive to separate all the different alloys once they are all melted together when those truck loads got where they were going.

[NyFirefighter357]

I'm guessing your heat is a little low, I think the oatmeal like consistency you are seeing is semi-solid alloy. Take a sample and test it with muriatic acid. I bet it doesn't fizzle.

[dimaprok]

I shot some 165gr with about 1% Zn on purpose in 40sw. Not a problem except they sized small (no springback as NO Sb) and leaded the barrel - also some went sideways. Alloy wasn't the problem. WW are whatever junk metal they find to use.I cast a lot of Zinc bullets from Zn wheel weights. Zinc actually has crazy springback. I had to make custom sizers that are 1.5 - 2 thousands smaller then target. Also initially I believed that Zinc shrunk smaller then lead and while this is true when you cast ingots but with bullets it comes out same size as lead. I doubt 1% Zn in lead would make it undersized.

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[35 Rem]

I recall getting that "oatmeal" type sludge back in the late 1970's and real early 1980's when casting so I'm not sure it's always zinc causing it. Unless there were some zinc weights showing up back then? Anybody know when zinc was 1st used for our beloved weights??

Back in those days my friend and myself would just turn up the pot, flux and stir in as much as possible, then spoon out any oatmeal that remained and keep casting. Never suffered all that much for it and we were selling bullets to a gun shop that wanted very good bullets for their customers.

[justindad]

It very well could be some impurity other than zinc. The main thing is - when I flux my COWW alloy with Root Kill, the alloy flows much better.