Using zinc as a hardener

[zxcvbob]

I have about 5 or 6 pounds of lead from stick-on WW's that's contaminated with zinc (from when I tho't all stick-on weights were pure lead and I got a bunch of steel and zinc ones mixed in a batch) It looks like oatmeal when it's melted, and it even had a little layer of pure zinc floating on top which I removed and threw away.

I still have it, as a reminder to presort my WW's and be careful about the temperature.

Would tiny amounts of this be good as a hardener for good lead that is too soft? I have a lot of good scrounged lead that is a little too soft for .41 magnum and .357 magnum boolits (works just fine for everything else) Someone has mentioned here before that zinc is a good hardener but it's easy to overdo it (and end up with oatmeal, and porous boolits if you can even pour it)

[JonB_in_Glencoe]

I don't know about using Zinc as a hardener in a Lead alloy...I'm very skeptical in fact.
BUT, when reading here once in a while that someone has some Zinc contaminated
lead alloy, I'm wondering if you can get some decent cast boolits if you crank up the Heat
of both the mold and the alloy, you'd lose any Tin component to oxidation in the pot quite quickly, but if you don't have any in there...Wouldn't it be worth a try ?
Jon

[white eagle]

I am sure that there is some residual
zink left in the mix
as long as you can pour it into the mold it should work ok
I had the same issue but I just threw the whole batch out .....20#or so

[Three44s]

Zinc is a scourge! Nothing good comes of it's inclusion in your boolit alloy!


Three 44s

[lwknight]

There are several people here that use zinc in their alloy to make hard rifle boolits.
Untill it comes down to a " have to " , I really don't want to deal with it myself.

[Ole]

Maybe if you had a mold that didn't have any sharp edges you could use it.

Round balls/shotgun slugs maybe?

(just tossing the idea out there/I might be way off base)

[mroliver77]

There are several people here that use zinc in their alloy to make hard rifle boolits.
Untill it comes down to a " have to " , I really don't want to deal with it myself.
I would like to hear from anybody that does. This is the first I have ever heard this. My limited experience is that the zinc does not really alloy but just kinda floats through the melt causing inclusions and nasty oxidation that ruins mold fillout. I have been wrong before and have learned new tricks when presented with evidence.
Jay

[clodhopper]

I have tried, but the results are not what I expected.
15 pounds of wheelweights got it good and hot and threw in a couple zinc Wheel weights, They melted slowley.
The alloy started to crud up.
Stirirng, it looked like good stuff under the dross, multipul fluxings yeilded more and more light foamy mettalic dross on top the melt.
I poured the metal into ingots was careful to store it plainy marked away from other lead.
Some months later I melted it again, this time, I just pushed the foamy dross back, got some clean lookin alloy in the dipper and poured some .22 cal bullets.
The bullets came out shiney with pretty good fillout.
Hardness testing that same day with lee's tool gave me about 6 bhn.
I saved the bullets I cast and plan to check the hardness again after they age for a month or so.

[docone31]

I do a lot in zinc.
I add the lead to the zinc in the melt. I found it did not mix well the other way around.
It needs heat, both the mold, and the melt. I also found, the mixture that worked real well was around 50-50.
Sizeing is hard on the die, but they fire well and there is no leading. I have been doing this for a couple of years now.
If, the melt is not mixed correctly, you get the zinc in spots. After water quenching, it shows up as dark spots. They also fire ok.
So far, so good.
I can push them faster than pure lead if I am not paper patching them.

[seppos]

I also had one potfull of contaminated alloy.. It was like trying to cast boolits with half melted lead, but I kept on pouring it to the molds.
Boolits (316299) did not show any problems with the filling, so I finished the pot..
The sprue cutting was bit harder, but I did not see any other issues with it.

S

[reloader28]

I had 2 twelve pound batches that I missed a zinc WW in and it was too hot. I left those 2 batches of ingots in a seperate coffee can.

I aint about to throw out any lead so I just added it in about 1 contaminated ingot for 11 good ingots and never had a problem.

I did get some lead from a guy a couple months ago that melted down WW into an old valve cover. When I remelted it down to my ingots it was a little foamy. I think in that 30lbs he must have had 1 or 2 zinkers slip in. I kept it all seperate and mixed it in the 11-1 way and never had one problem.

I only use this alloy for the pistol boolits not rifles, but I think it does make them a little harder. Its the only reason I can come up with that I got a 15 BHN from an air cooled WW boolit. (But that was also from the "unknown" valve cover lead too, so it could be something else). I'm sure if you played with zinc a little you could probly get a pretty consistant hardness.

So far, when the shot boolits are gathered back up and resmelted back in to ingots again, the zink is almost completely diluted. I only throw in a handful of used boolits to a 13-15lb potful of lead and only some of these boolits had the zinc to start with. If they were fine the first time, theyll be even better when they are melted back in with fresh lead.

[fecmech]

I screwed up a couple of smelts this fall with zinc. I set the first batch of ingots aside but later when I screwed up another one I lowered the heat and was able to get some out of the mix but not all. I then figured what the heck and threw in 3% tin and ladle cast a couple bullets out of the smelt pot, they came out OK. I have since cast that alloy with no trouble and good accuracy with my handgun loads. The ingots test at around 16 BHN (I have no way to test the bullets). This spring I plan to try and clean up the first batch that I messed up.

[HollowPoint]

This sounds like one of those bullet casting "Old Wives Tales" in the making.

I've heard of few -if any- bullet casters that have actually tried with success, the alloying of zink/lead for themselves. It seems like we're just passing along second hand information and assuming it to be true.

It may very well be true. I don't know either; I've never deliberately tried it but I think I will.

Other than "Fill-Out" problems and the time wasted associated with this, are there any harmful effects to the bullet caster or the gun? I know of lead itself as being potentially harmful to the bullet caster but not to my guns.

My first attempts at bullet casting were done in a state of complete ignorance. I threw all different kinds of wheel weights into my melting pot. Many of them floated to the top of the mix and were obviously steel weights. Others floated to the top for a while but eventually melted. (zinc)

As we all know, there are guys here that make and shoot alloyed lead bullets. There are also guys on this forum that make and shoot zinc bullets.

Just because we may not have (as of yet) found success with using zinc as part of our alloy doesn't mean that success can't be had.

I think it's just a case of not enough guys having put enough effort into finding a repeatable working method to that success.

Since lead may be slowly going the way of the dinosaur, perhaps it's time we make a concerted effort to find that "Repeatable Working Method" of using zinc as part of our alloy.

In hind sight I know now that my initial bullet casting attempts contained a fair amount of zinc wheel weights. I do recall the clumping at the top of my melting pot but, like I said, I was totally ignorant and didn't think anything of it.

A little fluxing, a little more fluxing and a little more fluxing seemed to get rid of most of the clumping.

As long as my melting pot was hot enough to melt just about everything I'd thrown into it, I just assumed it was all melted lead. Under those conditions, I don't recall to many "Fill-Out" problems; and I was completely clueless about tin content or loss.

I've rambled on and said all of this to get to the point I'm eluding to. My initial attempts at bullet casting had to have certainly contained a fair amount of zinc in my alloys; even though I didn't know enough to refer to them as alloys.

Since I've begun delving into High Velocity rifle bullet casting, I'd like nothing better than to find a way to use zinc as a component of my alloys. I think it would go a long way toward giving me sufficient hardness -while still retaining some malleability- instead of the brittleness and abrasive-ness that antimony gives.


HollowPoint

[clodhopper]

I do a lot in zinc.
I add the lead to the zinc in the melt. I found it did not mix well the other way around.
It needs heat, both the mold, and the melt. I also found, the mixture that worked real well was around 50-50.
Sizeing is hard on the die, but they fire well and there is no leading. I have been doing this for a couple of years now.
If, the melt is not mixed correctly, you get the zinc in spots. After water quenching, it shows up as dark spots. They also fire ok.
So far, so good.
I can push them faster than pure lead if I am not paper patching them.

When you say 50/50 you mean 50% zinc?
Have your experiments used wheel weights or just lead?
wondering if the antimony has any effect.
Any thoughts on tin in the Zn/Pb alloy?

[lwknight]

When you say 50/50 you mean 50% zinc?
Have your experiments used wheel weights or just lead?
wondering if the antimony has any effect.
Any thoughts on tin in the Zn/Pb alloy?

WOWsers , thats quite different from my experiments. I never tried a high zinc a lloy. I know that in low zinc alloys , you can only get a small percentage of zinc to stay in the lead. And it only trakes a few days to harden up a lot.

Maybe lead contaminated zinc works better than zinc contaminated lead?

[geargnasher]

My understanding of the Pb/Zn binary is that at 50% concentration the mix must be nearly 1500 degrees to be in stable solution, and as it cools from there the two try to separate, then zinc precipitates as a solid in a lead/zinc solution, then as the cooling continues and the Pb/Zn depletes more of Zn freezes out the stuff finaly freezes at about 600 degrees leaving Zn, Pb/Zn as an intermetallic (like Sb/Sn) frozen in globs within a mostly lead solid solution.

Basically, it would be like a bowl of Jell-O with lots of fruit chunks in it.

I'm not saying it doesn't work, it just sounds really tricky to work with. The way the phase diagram looks, castable alloys would only be able to have a few percent lead or a few percent zinc to work with conventional boolit casting methods, and mostly zinc boolits seem to require special moulds since the material is too hard to cut with a regular sprue plate.

Gear

[Bulltipper]

There is a wealth of information on alloying, casting temps, boolit molds, and everything to do with boolit shooting on the Los Angeles Silhouette Club website. Get a pot of coffee on and enjoy!

[JonB_in_Glencoe]

The way the phase diagram looks, castable alloys would only be able to have a few percent lead or a few percent zinc to work with conventional boolit casting methods, and mostly zinc boolits seem to require special moulds since the material is too hard to cut with a regular sprue plate. Gear

this would explain why "reloader28" had success with his 11 good ingots to 1 contaminated ingots, making the Zn content about 0.45% at most, just guessing that his contaminated Ingot was no more than 5% Zn.

to Quote reloader28, "I aint about to throw out any lead so I just added it in about 1 contaminated ingot for 11 good ingots and never had a problem."

[runfiverun]

keep the zinc under 2% it'll add hardness and work fine.
shoot for 1.5% guesstimate.
it's soluble.

[HollowPoint]

Does anyone know of any metals that do mix/alloy well with zinc?

My reason for asking is, if there is such a usable metal, in small amounts it may be used as a component of your alloy to allow zinc to mix well with lead.

As an example: I accidentally dropped some aluminum shavings from my mill while back while I was casting. Those small aluminum shavings seemed to disappear/melt into my molten lead before I could scoop them out.

I was just wondering; if aluminum will mix with lead evenly enough, will zinc mix with aluminum? If so, will alloying zinc with small amounts of aluminum, then mixing this combination with lead; will the aluminum act as a catalyst to help distribute the zinc in my melting pot evenly enough to mitigate the clumping/separating that tends to take place when zinc is mixed with lead alone?

Please understand, I'm using this aluminum example in hopes of getting an answer to my original question. (It's only an example) Are there any metals -like brass or copper or aluminum- that we might be able to use in small amounts as a "mixing-catalyst" to keep the zinc component in such an alloy from wanting to clump up?

Just the other day during a short casting session, I threw a couple of cast bullets that I'd copper-gas-checked into my pot thinking I could fish out and reuse my gas checks when they floated to the top but, that never happened. I can only assume they also melted into my molten lead.

In small amounts, I know that both copper and aluminum will melt into my existing molten lead alloys. I'm wondering if they will also melt into molten zinc; and if they will; what effects that will have in the zinc alloy that's created by doing so? Can this zinc/copper or zinc/aluminum alloy then be successfully mixed with my bullet casting lead alloy?

Wether it will work or not, I hope my question makes some kind of sense.

HollowPoint

[L1A1Rocker]

I've read somewhere on this forum that a 2% zinc makes a very good alloy for boolit casting.

I've also read a thread on this forum where excess zinc was removed by fluxing with sulfur.

[reloader28]

HollowPoint
HOLY MOLY, how hot do you cast at?

[HollowPoint]

Generally speaking, when I start my melt I turn the pot all the way up.

Once my alloy has completely melted I then turn it down to the temperature just below the point of
giving me frosty bullets.

The small amounts of copper and aluminum I mentioned in my earlier post got into my pot about the time everything else in it had melted.

According to my thermometer, the hottest my pot will get with a full pot of alloy is a hair below 900 degrees. Wether I have an accurate thermometer or not is up for debate but, the fact that it melted those small amounts of copper and aluminum tells me it's pretty close.

HollowPoint

[lwknight]

You did not melt copper in the casting pot.
Copper will disolve in a lead/tin alloy.
The aluminum must have disolved too because once again , you did not melt aluminum in the casting pot.

[zxcvbob]

Mercury will aggressively dissolve aluminum at (and below) room temperature.

[45-70.gov]

Mercury will aggressively dissolve aluminum at (and below) room temperature.

what does mercury do to zinc and lead?

what if once the zinc were dissolved then added the the mix?

i had a batch of led i suspected was contaminated with zinc
just put it into ingots and set them aside......
after this thread i think i will try to slowly add them to future batches

[zxcvbob]

what does mercury do to zinc and lead?
Nothing. It has to do with aluminum dissolving into lead at not-particularly high temperature.

[jbunny]

molten zinc is highly corrosive and will disolve iron, aluminum, copper, ect.
i experimented with 50-50 mix and with tin it would alloy with hotter than normal
casting temp. don,t ask for temp #,s.

[leadman]

hollowpoint, you will probably find the gas checks stuck to the sides of your pot. I have thrown many gas checked boolits back in the pot and found them later stuck on the sides, even after several fluxings.

[lwknight]

molten zinc is highly corrosive and will disolve iron, aluminum, copper, ect.
i experimented with 50-50 mix and with tin it would alloy with hotter than normal
casting temp. don,t ask for temp #,s.

When zinc disolves copper you will have to turn up the heat somewhere along the line because you will be making brass.