Did I get zinc-ed?

[CGT80]

I traded some sheet lead for some 1 pound ingots that were supposed to be wheel weights. They rang like wheel weight lead when dropped on concrete, maybe even better. They were silver and semi bright. I melted down the 8 or so ingots in my lee 20 pound bottom pour and set the PID to 750 degrees. That temp worked well for my last unknown alloy.

I had a creamy substance on the top of the melt and some impurities. It didn't seem to cast very well and it poured slow from the spout. I ran the temp up to 800 then 850. I cast a few boolits but the fill out wasn't that good. I added what I thought was section of bar solder. It helped a little with fill out, but not enough. I then dropped in a small chunk of tin from rotometals. With a nice hot mold and the melt at 850 I was able to get OK boolits from my RCBS 45 225 steel two cavity mold. This mold seems pretty forgiving as it has a single lube groove and a nice tapered round nose. I did get a few 30 cal RN PB boolits from this alloy also.

I ended up using the alloy for the 45 cal boolits. I figured in my 45 colt brass and 6.0 grains of red dot (750 fps) or in a 1911 that alloy wouldn't matter so much. I didn't want to run alloy that may be bad through my rifles at 1100-1300 fps. The pistols are easier to clean out, too.

I had issues with the pour spout freezing (mapp gas torch fixed that) and always had a little lump to the melt. I could never get all the lump out when I skimmed it off, so I dumped it back in and just used as much of it as possible. I was getting gold, blue, and purple colors on top. I fluxed with pine saw dust and stirred it in real well with a metal spoon. I also used some bullet lube and mixed it in. The boolits never got super frosty, even with a very hot mold.

I read a bunch of other pages here, and still am not sure if I had zinc or just an odd alloy that I wasn't used to. I have not measured the boolit diameter yet, or weighed them.

If the boolits look good, are they ok to shoot? If they have some zinc, are they still ok to shoot?

Thanks guys

[mikeym1a]

I have no idea. What did the slugs weigh after casting? Zinc is much lighter than lead alloy. You might have gotten some linotype, which is much harder than WW metal. The gold, blue and purple usually comes with lead being rather hot. Don't know. But I'm interested.

[Defcon-One]

MikeyM1A, Linotype melts and pours better at lower temps. It was not likely Linotype as that would cast the prettiest bullets and flow well.

No way to know if it was Zinc without testing it. Skim off some dross and do the acid test with pool acid or The Works toilet cleaner. Lots of bubles will indicate Zinc. It cleans toilets really good, too.

It could just be a very high Antimony alloy!

[.357MAN]

I would say pure lead if it wasn't for the creamy substance on the top of the melt.

When I started casting I was using lead scrap that was close to pure lead and I could not figure out what was wrong when casting at 700-750. As it turns out pure lead needs way more heat to flow out in a mold, and my alloy likes 850+ to keep from getting wrinkle.

Another clue is that they didn't frost. Anything high in antimony will frost well before the temperature you where running this at, and I have not been able to get pure lead to make frosted boolits.

If you weigh the boolits and they are heavier than usual then it is most likely pure or close to pure.

My final guess is that it's close to pure lead with a contaminate in it.

If it is pure lead it could lead the barrel, but it is really easy to get the leading out compared to hard alloys.

[CGT80]

The RCBS 45 225 boolits came out at 225 grains before sizing and lube. An older batch of the same boolit from different alloy is just slightly heavier (maybe 4 grains), but they have lube. I didn't measure the diameter yet.

I got a very light frosting, but I would have expected more at that lead and mold temp. I got much more frost from a brass mp mold when I ran it too hot. The boolits actually cracked as they cooled on the towel.

After I ran out that lead, I switched back to a batch I was previously using. I scraped the pot and got all the crud out of it, between uses. The sides of the pot were easy to clean up. The bottom had a small amount of lead that was tough to get off. The pot has only been used 6-10 times. The alloy from before looked like liquid and didn't have the creamy texture. I also had to close down the spout, as it was flowing easily with only a third of a pot of melt. My temp was 750. I fluxed with sawdust and it looked fairly clean in the pot. My bullets look like they may have some impurities though. I even refluxed with the white powder flux I got from midway. It foamed up black and I scraped the junk off the top. I added a small chunk of tin to help fill out since the edges of the lube grooves were a bit rounded. I ran mold from cool to very hot. I got some frosting.

The odd part, is that one bullet would have good fill out with crisp edges, then the next would have rounded edges. I have cleaned the mold with brake cleaner a few times and I have 100+ boolits from it since I pulled it out of my ammo box and cleaned off the oil.

I will try cleaning that mold with a toothbrush and degreaser. Will a brass brush hurt the cavities of a mold?

I sure wish the guns for scanning metals weren't so expensive. It would probably be much easier to know what we were dealing with.

I also have an RCBS 30 115 SP GC steel mold, 2 cav, that has an alignment pin hole that must be rough or off. Both pins go in the hole toward the handle (when not attached to handles) and neither pin will fully seat into the other hole. I had cleaned up the inside of that second hole with a drill bit and it worked for a while, but it is hard to fully close the mold again. My RCBS 45 225 mold works fine on the same handles. I thought maybe the handles were getting miss aligned as I used the mold. I will search the molds section again, but does anyone have info or links that may help with this issue?

Maybe one of these days I'll get this process down. Thanks again. Chris

[.357MAN]

Well, I was dead wrong about it being pure, and its not the first time I was wrong. Kind of makes me feel silly for even interjecting my opinion.

[CGT80]

I have some muriatic pool acid, so I dropped a couple boolits in it and some slag. The 45 225 boolits and slag from the problem alloy created bubbles. I dropped in a couple boolits from the second alloy I used the other day and they didn't bubble. The second alloy was the one that made one nice boolit and then one rounded edged boolit, alternating between the two. The second alloy didn't have the mush on top either. All of the lead darkened from being in the acid, but the second set only darkened a little (with no bubbles that I noticed) and the first set from the creamy alloy, turned very dark.

I should probably try the acid test on some sheet lead and some new wheel weights that I have to see if it always turns dark. That acid is nasty though. If I had a little eye dropper bottle to just put a drop on a sample, it would be less of a health risk. I am wondering if the second alloy had a small amount of zinc (different source than the creamy batch) or if my mold was just not clean or the melt not clean enough.

Has anyone else had experience with the acid test?

I measured the boolit diameter with a micrometer. The 45 225 were plenty big. I use a 452 sizing die and the bullets were all bigger. The 30 cal bullets from the second batch of alloy were about like the last time I cast with that mold, maybe just a tad smaller. The mold is a 308 and it drops a little oval with measurements from 308-311. My 311 sizing die usually hits 60% of the sides of the boolit, but this time it was only a stripe on each side of the boolit. I have beagled this mold before and come out at 311.

Right now I am working with 1 pound ingots, but I have bigger chunks to melt down over the fish fryer and some range lead. I am trying to learn ropes on the small scale before I make a mistake on a 50+ pound batch of lead.