Lead/Zinc alloy wheelweights?

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  • Last Post 26 February 2015
coffeeguy2 posted this 23 January 2015

OK, I've not been focusing much on wheelweights lately since in my area the last couple batches I've gotten are around 90 percent zinc/steel. Anyway, I sorted through a bucket of wheelweights the other night I got for free and some felt dense enough to be lead, cut easily with pliers, but had a little bit of a ring to them, kind of in between known lead and known zinc WW's...I set these aside in the “add carefully to pot” category. As far as I'm concerned, as long as they melt OK at the right temperature, and cast OK, no oatmeal in the pot, etcetera I'm just gonna cast/shoot as usual, but out of curiosity has anyone noticed weights like those before?  They don't 'thump', don't 'tink' like zinc/steel, and if not for that I'd never have noticed them as being 'different'.

 

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RicinYakima posted this 23 January 2015

This is how I first discovered zinc contaminated WW's 20 years ago. It began with cars imported from Japan and Korea as they used anything that would melt, a lot of old carburetors, fuel pumps, etc. mixed into the lead scrap. It took us a couple of years to figure out what was happening. Use at your own risk, as this is about 1% zinc, will melt at 670 degrees and you can not dilute it out or remove it from the alloy. FWIW, Ric

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coffeeguy2 posted this 23 January 2015

Hmm...Good to know! I guess I'll just proceed carefully with them, if my melt gets out of whack I keep enough pure lead on hand to get the percentages back to a manageable point. It's slow going, but I'd rather spend the extra $ on propane and do smaller batches than melt a huge quantity and deal with a bigger 'oops'. Thanks much!

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RicinYakima posted this 23 January 2015

You can not “if my melt gets out of whack I keep enough pure lead on hand to get the percentages back to a manageable point". Zinc will round the edges of drive band at one part in ten thousand, and form indentations at 1 in 100,000. That is the risk.

So for several years I melted all of the questionable one together. (This is after I tried what you want and ended up with 94 pounds of junk starting with 10 pounds in a Lee pot. My biggest loss was the three pounds of tin I tried to make work.) Blend one tablespoon of questionable WW's with what is needed to make one ingot, then is a separate pot, try to cast bullets. If they are not perfect, scrape your questionable alloy.

HTH, Ric

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coffeeguy2 posted this 24 January 2015

Umm, yes I can, and have javascript:emoticon(':wnk:', 'images/emoticons/winking0071.gif') ...Granted, there's no practical way to get zinc out of a melt once it's in there, but 'manageable' for me means decent casts with sharp edges and little to no blemishes. Those are my plinking loads when contamination happens...The batch goes into quarantine of sorts and I make the most of it either as bullets or fishing sinkers.

One part in ten thousand is the equivalent of a one-ounce zinc wheelweight mixed with over 600 pounds of bullet alloy...One one-hundredth of one percent. For poor fillout be noticeable, it's more like one quarter of one percent; more like 4 oz. in 100 lbs of alloy. You make a great point in that we should strive to keep zinc out of our melt completely, but with as wheelweights change (not like there's a 'certified wheelweight alloy' standard anyway)it becomes more and more likely. Small batches and frequent sampling/testing is the way to go. :wnk:

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OU812 posted this 24 January 2015

Casting hotter (800-900 degrees) will usually remedy poor fill out of bullet...especially smaller 22 caliber. If not I would say you have a poor casting alloy.

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Bongo Boy posted this 04 February 2015

I don't think there's any way in the world you can 'feel' the density difference between lead alloy that contains zinc, and alloy that doesn't. You'd be more likely to tell the difference by color, ductility or phase of the moon. I doubt you could even measure the difference outside a lab. So...I'd say forget about that method.

It seems to be true that most clip-on wheel weights are decent, while stick-on are not. I don't know if that's a reliable rule or not. In my limited experience, really severe zinc contamination will show up right away at the ladle...the stream from the ladle is in the form of a long, thin 'string' and tends to stick to the bottom of the ladle. The longer and stringier it is, the more zinc I assume there to be. I have run upward of 780-800F and after about 4 mold-fills of casting, turned the ladle over and wiped the bottom clean with my glove. This will allow me to get a few pours from it with a controllable stream. The challenge here is to get enough control over the stream to get the stuff down into the sprue hole without just gumming up the hole entirely. I've actually had the ladle maybe 6” above mold to get the stream to swirl in. A real PITA.

Tonight, I started pouring with the pot at 780F and I suspect there's some zinc in the mix. A relatively thin slurry of slush on the surface of the melt, but nothing to worry me much. A modest stringiness to the stream out of the ladle, but very little 'sticking' to the ladle or flow-back across the ladle bottom. Bullets are beautiful in most cases--at least by my standards.

Since I have no earthly idea what the composition of my lead is and have no way of ever knowing--I get along with what I have. I throw bullets back in the pot that don't fill completely, all other bullets end up going downrange. All my lead is already in ingots, and most of those ingots are quite similar in appearance--so it isn't until it's melted in the pot that I can even suspect what it is. Regardless of what that goop is in my pot, it's almost certainly going to end up as a finished bullet with few if any visible defects that I care about--and there are quite a few that I simply don't care about if I'm making 40 cal hosing bullets.

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Bongo Boy posted this 05 February 2015

For an update on this topic from my own perspective, see the '44 magnum beginner bullet' thread, where I include photos of the bullets I just talked about above. At this level of magnification you can see many defects and a general 'nastiness'...holding the sized, lubed and loaded bullets assembled into cartridges, I fail to see a problem.

In this case, shooting is the only test that makes a difference to my mind. We'll see.

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coffeeguy2 posted this 19 February 2015

True enough. I guess I wasn't specific when I talked about 'feeling' density; I meant strictly lead versus zinc wheelweights. With a lead/zinc alloy it's anyone's guess.

There was a really neat article in Handloaders' Digest from around 1990 or so that detailed casting bullets with zinc...I seem to remember that 'stringiness' you talked about, and the article recommended casting at higher temps and enlarging the holes in the sprue plate (for those interested in trying it, as for me I'll stick with what I know).

As far as that 'phase of the moon' thing, LOL, yes, that's probably a far better way for lay folks such as myself to tell what exactly is in my alloy. Glad to take advantage of casting with wheelweights as long as I can in the meantime!

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billglaze posted this 26 February 2015

I figured I had some zinc contamination when my previously 200 gr. bullets started weighing at 187 gr. and a Brinell of 35+ vice the usual 11-13. Also very hard to run through the sizing die. After looking in the Chemistry and Physics Handbook I discovered a roughly 100 deg. difference in melting points, and I had the “perfect” way to discriminate: just start the pot with a bunch of known good alloy at a low temp. and, when the lead was barely melted just put in the questionable weights (with one eye on the Lyman thermometer.) If it floated, pick it out and discard.
Really didn't work so good. Even at the lower temp, some of the weights were half (or more) melted before I could pick them out. As I type now, I can't yet differentiate. Only thing I can tell; despite dire predictions, the mold(s) have been filling well, and the bullets, as of a short test, are shooting as well as the “good” alloy. However, much more comprehensive shooting will be required before obtaining certifiable results. Bill

In theory, there's no difference between theory and practice. In practice, there is. My fate is not entirely in Gods hands, if I have a weapon in mine.

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