Casting Zamak 2

[arawakstorm]

Looking for help here.....I have recently attempted to cast .44 mag bullets using Zamak 2 in the Lee aluminum molds.......molds are no longer usable and the alloy "froze" to the mold. Any advice? Thanks!!:(

[500MAG]

Possibly heat the mold to the Zamak melting point. I think there is close to a 500 degree difference between zamak 2 and aluminum. May ruin the mold in the process can't hurt if it is ruined already.

[Nobade]

Aluminum dissolves in molten zinc. Zamak is a zinc/aluminum/copper alloy IIRC.

You really need a mould dedicated to zinc alloy if you want to make bullets from it.

[I'll Make Mine]

As noted, aluminum dissolves in molten zinc -- and there are a number of solders for bonding aluminum that are mostly zinc; the solution at the interface (after scratching the aluminum oxide layer to allow the zinc to react with the aluminum) bonds these solders to the aluminum almost as tenaciously as bronze weld filler bonds to steel.

Your aluminum Lee die is toast; the Zamak bullet is probably welded to both halves. Heating until the Zamak melts might let you pour out most of the Zamak, but probably won't completely release the bond where the molten alloy welded the two halves together along the joint in each cavity.

If you really want to cast Zamak bullets (why, hardness?), get an iron mold; the dies used for commercially die casting zinc alloys are iron or steel, and don't bond to the alloy (at least with proper surface prep).

[arawakstorm]

Thank you very much! I'll try this out with an iron mold. RE: surface preps.....which all around type can you folks recommend? A type/brand that can be used on aluminum and iron/steel molds?

[theperfessor]

Well, I don't use mold release or anything else (including smoke) in my molds and they all work fine after a little deburring and some break-in. Never tried casting zinc however.

[Multigunner]

An old article on cast Kirksite bullets in American Rifleman stated that any contamination by lead residues could result in a crystalizing of the bullet surface months later on.
This corresponds with a similar warnings in instructions on die casting of parts, and articles on degradation of antique die cast toys made in Europe in the 30's and 40's.
"Zinc Pest"
http://en.wikipedia.org/wiki/Zinc_pest
Its recommended that when casting kirksite that you use pot, ladle, and mold blocks dedicated to the purpose and never use these with lead or alloys containing lead.

Tough break on ruining the aluminum blocks, but I never cared for aluminum blocks anyway.

[arawakstorm]

Many thanks to all of you for your comments. This is GREAT!!!

[I'll Make Mine]

Thank you very much! I'll try this out with an iron mold. RE: surface preps.....which all around type can you folks recommend? A type/brand that can be used on aluminum and iron/steel molds?

For a start, try it in something less expensive than an iron bullet mold ($70+ and up for an experiment?!); you could simulate the effect by getting a piece of scrap cast iron or even hot rolled steel from the hardware store, cutting it in half and filing the cut smooth, then drilling a hole on the cut line. Clamp closed, preheat with a torch, and pour -- just to see if you can separate the mold and get the resulting casting out, before you send a Lyman or RCBS mold after that Lee.

And you still haven't said why you want to cast bullets out of Zamak -- there's a good reason bullets are still made out of lead (alloy) after more than five hundred years: because it works! Zamak bullets might be nice to plate and hang on a necklace, but they aren't going to shoot well, most likely...

[arawakstorm]

The thought was that since the zamak 2 was a much harder alloy than the lead (linotype), it might be a more effective round against wild boar.......

[375RUGER]

doesn't matter if it's harder. does it out weigh a lead slug the same size?
A heavy slug will penetrate better than a light one. I wouldn't use straight lino either. it's a bit brittle.
Cast 'em with hardball alloy, hardball alloy penetrates good. Want harder--heat treat.

[arawakstorm]

Thanks alot for your help and comments. I'll give this Hardball Alloy a try. I'm completely new at this......quite a learning experience!!

Thanks again, and I'll post to let all of you know the results.

[runfiverun]

those must be some huge wild boar.
20-1 lead to tin penetrated about 10 million bufallo enough to make them nearly extinct.
reduced thier numbers to around 1,000 when it was done.

[I'll Make Mine]

Well, I'd consider wild boar dangerous game, typically shot at much closer range than all those bison, and often when trying to hunt the guy with the gun. One shot kills highly desired -- but still, a heavy boolit cast from an alloy a little harder than wheel weights should be capable of enough penetration to pass through from stem to stern, or break into the skull to get to the soft squishy interior. This is assuming, of course, that you have enough gun; .44 Magnum certainly qualifies if the loads are above the Special level (a .357 Magnum ought to be enough, except that more gun is really good insurance with an animal as aggressive as a boar).

[btroj]

Water dropped wheel weights are hard enough, and tou enough, to penetrate about anything that needs shooting.
I wuld be willing to hunt the big bears with a 50/50 WW /pure lead water dropped bullet in the fit gun.

Use a heavy enough bullet and penetration won't be an issue, even with 20-1.

Hardness isn't an issue as long as alloy and velocity are in alignment.

[Thompsoncustom]

I have casted quite a bit of Zamak and I have also wrecked a lee mold just like you. I find it helpful to get a nice buildup of carbon on the mold to help protect the mold from the zamak. I have been thinking about trying to anodize my aluminum zinc-only lee mold and see if that would help even more. Also try to keep your mold just hot enough to keep the bullets looking nice and no hotter because I think when I killed my first one I got it to hot.

Yes the bullets are a lot harder they don't even really compare to lead bullets but what they gain in hardness they loss in mass I think my 125gr mold through 80gr zamak bullets and the 105gr mold throws 60gr. You can also mix pure Zinc and Prue lead together and unlike WW they mix nicely so you gain some strength and lose a little mass. Have fun trying to figure out zinc bullets is a whole-nother game of it's own.

[I'll Make Mine]

You can also mix pure Zinc and Prue lead together and unlike WW they mix nicely so you gain some strength and lose a little mass.

Lead (even pure lead) and zinc don't alloy well at all; the maximum amount of lead zinc will dissolve is under 2%, and the maximum zinc you can dissolve into lead is just over 2% (assuming I don't have that backward). In between, you'll get an alloy that, if it cools quickly, contains tiny domains of lead-in-zinc and zinc-in-lead; if it cools slowly enough, these will segregate by density and you'll get lead-in-zinc at the top (zinc with 1.6% lead is lighter) and zinc-in-lead at the bottom. Worse, the melt in your pot will segregate, pouring mostly lead (until it runs out) from a bottom pour pot, or mostly zinc (unless you dip deep) from a ladle pot.

The weight variance and potential imbalance of the resulting boolits make attempts to alloy zinc and lead a bad idea, and are behind all the warnings to use separate pot, ladle, and mold for zinc alloy (to avoid contamination of your lead alloys).

[Thompsoncustom]

From experience I have to disagree they alloy just fine not sure what the difference is but with WW if I add over probably 2% you can see it floating around in there as it won't mix and doesn't cast well but with 50/50 zinc-lead it seems to mix and pour fine, I don't know the science behind it but that's what works for me as long as you have pure of both.

Here's a link of my zamak experience
http://castboolits.gunloads.com/showthread.php?t=136800&page=2

[Thompsoncustom]

From experience I have to disagree they alloy just fine not sure what the difference is but with WW if I add over probably 2% you can see it floating around in there as it won't mix and doesn't cast well but with 50/50 zinc-lead it seems to mix and pour fine, I don't know the science behind it but that's what works for me as long as you have pure of both.

Here's a link of my zamak experience
http://castboolits.gunloads.com/showthread.php?t=136800&page=2

Also here's a link of another guy that had good luck with the 50/50 mix.
http://castboolits.gunloads.com/showthread.php?t=64166

[I'll Make Mine]

It's been known for over 150 years that lead and zinc, even starting from pure, don't alloy well. Here's my source for what I wrote above:

Proceedings of the Royal Society of London, Vol. 11 (1860-1862) (http://www.jstor.org/stable/111941)

If you're getting pours that look like good alloy, check the density -- you'll find it's almost that of lead, or that it's almost that of zinc, or you may find that hardness (and related density) varies through the boolit due to segregation of a physically mixed (as by stirring immediately before the pour), but not dissolved melt.

[I'll Make Mine]

Also here's a link of another guy that had good luck with the 50/50 mix.
http://castboolits.gunloads.com/showthread.php?t=64166

Read the whole thread -- he found out he was getting almost pure zinc off the top of a segregated pot.

[Thompsoncustom]

That could be if they separate and the zinc floats on top of the lead I would never see the difference it just doesn't oatmeal like zinc and WW do. Thou if the zinc floats on top you could make hardpoint bullets the same way you make softpoints that might be worth a try.

[I'll Make Mine]

if the zinc floats on top you could make hardpoint bullets the same way you make softpoints that might be worth a try.

The problem with that is that the melt segregates, not just the cooling boolit, and there's no way to be sure you've stirred it the same way or gotten the same proportion of top melt and bottom melt each ladle -- meaning, you'll get boolits of different weights, because there's much more difference in density between lead + 2% zinc, and zinc + 1.6% lead, than between pure lead and wheel weight. And you'll still get soft points, because the heavier alloy (lead with a little zinc) will go to the nose (assuming your molds are base pour, like most).

Unfortunately, a boolit cooling in the mold probably won't stay liquid long enough to get consistent segregation of the melt to give a soft point or hard point; instead, you'll get random chunks of the higher-melting alloy (zinc with a little lead) distributed through the boolit, giving balance problems and inconsistent driving band hardness, on top of the weight variation from one to the next. All bad for accuracy, and the end result really isn't any better for anything than #2 alloy or half and half linotype and pure or linotype and WW.

If you *really* need hard driving bands (potentially useful for shooting cast at 2000+ ft/s), look around on YouTube for a video on casting boolits with brass rings fitted into the driving bands of the mold (this also produces boolits only a few grains lighter than standard casting, as opposed to zinc at about 60% density). Do this with a gas check design, and you might get boolits you can push as hard as jacketed -- but the effort of making the driving rings and getting good castings with them in the mold seems excessive when you can just buy jacketed bullets for that kind of pressure/velocity.

[Thompsoncustom]

Couldn't you fill the mold half up with lead and wait for it just to cool and than pour the zinc on top?

I also have only cast zamak 3 not zamak 2 which also has copper and I think the brinell hardness of 100ish. zamak 3 makes some super hard bullets I would have curious to see how much stronger zamak 2 is.

[I'll Make Mine]

Couldn't you fill the mold half up with lead and wait for it just to cool and than pour the zinc on top?

That would give you a soft point again (base pour mold, right?), but you'd still have a lot of weight variation, unless you can pour precisely to the same lube groove each time (bet you can't!), a slanted interface (= unbalanced boolit), unless you can keep mold exactly level during and after the first pour (possible, but not easy) *and* the second pour (zinc will remelt the lead at the interface), and you'd still have to keep that mold for zinc (the rule, with good reason, is to keep all your zinc equipment away from the lead stuff). Pour the zinc first to get a hard point boolit, it'll avoid remelting with the second pour, but either way you'll have the mold either too hot for lead or too cold for zinc.

Pure zinc boolits actually do have some use -- they're lighter than lead, and harder than even straight lino, which makes them useful for things like duplicating semi-auto light jacketed loads (though they're also brittle compared to most lead boolit alloys, so not very good for hunting or defense). Zamak alloys, however, are zinc-aluminum-copper, and all are harder than pure zinc, as well as still lighter, and they have a slightly higher melting point than pure zinc.

Oh, and you *still* shouldn't attempt to cast zinc in an aluminum mold, unless you like making wall hangings of you welded-shut Lee molds...

[Thompsoncustom]

ya base pour I had that backwards. So the zinc would have to go first and I don't think they would be good for much as the weight would be different every time I'm sure(I wouldn't even try to get it in the same groove lol) might be something fun to play with that's the whole reason I start casting zinc just to play around. And ya I am casting with a alum mold still I add add the alum to the mix till it won't take anymore in hopes that it will leave my mold alone :).

[I'll Make Mine]

And ya I am casting with a alum mold still I add add the alum to the mix till it won't take anymore in hopes that it will leave my mold alone :).

So you're casting an unknown alloy, too. If you want aluminum bullets (which is more or less where you're headed -- as I recall, zinc and aluminum are completely miscible, in the absence of other alloying elements; IOW, you can have anything from zinc with a trace of aluminum, to aluminum with a trace of zinc; your limitation is the increase in melting point as you add more aluminum), why not just buy some conductor grade pure aluminum, which is actually softer than Lyman #2, and turn your bullets from rod on a lathe or swage them in a heavy duty die and press set?

Aluminum bullets have been tried a number of times, BTW -- they didn't catch on because a fat, light bullet isn't a good choice for the things we usually use bullets to do, and for the things where fat and light are desirable, plastic and wood are better than aluminum. I looked at 'em a while back, too -- I figured I could get one up to 3000 ft/s from a 10 inch barrel in a .221 Fireball, but it looked like they'd lose velocity so fast it'd be a toss-up whether you'd hit anything beyond fifty yards. Useless for varmints, and no better for gallery loads than a plastic bullet.

[arawakstorm]

Happy Monday to All!!

I spent several hours this weekend casting several .44 mag bullets with 4/12/84 lead alloy using my "new" lee aluminum mold. Everything went smoothly. Thanks to all of you for your assistance and advice. I am also new to this "online collaboration" stuff, and it's nice to know that there is a forum out there for some really good information exchange. I will keep all of you updated as things move along.

Thanks again, and have a great week.[smilie=s: