Zinc casts OK is it still bad?

[86LG4T5]

I don't post often but Ive searched and haven't found an answer...

Third time I've bought lead on Ebay and this time it has some amount of zinc. Surface of the heated lead turns purple. No my lead isn't too hot. My mold won't fill out with this batch of lead leaving rounded corners and especially bases. No my lead isn't too cold. :razz:

Here's the kicker - I have a Lee production pot that has the flow valve underneath. If I hold the fill hole in the mold up against the flow valve when I open it, it forces the mold to fill out and I get perfect looking bullets - which still have zinc in them. Since I can get normal looking bullets I'm tempted to go ahead and use them even if they have zinc. Does a zinc bullet do something bad when it strikes a deer?

[swheeler]

I didn't know zinc contamination made the alloy turn purple on top,I thought that was an indicator of pure or nearly pure lead at high temp.

edit- or maybe some free copper in the alloy

[mold maker]

Zinc will change the weight of the boolit. As long as this is factored in, the deer wont have a clue.

[Smoke4320]

Just hit'em with the Kitchen Zinc :)

[runfiverun]

purple is generally an indicator of pure lead but it's commonly associated with a rainbow of colors.
the blue shows up when the ingot is cooled down.

okay let's say you have pure lead with some zinc in it.
that isn't a bad thing, zinc is a hardening agent to lead and if you can get it to cast then you have a boolit.
it would cast better with some tin in the mix and behave better when striking the target too.
you'll just have to work your loads to your alloy.

[xacex]

If it doesn't look like oatmeal you will be OK casting with it.

[dilly]

From what you have said I see no reason to conclude zinc. "Peacock" yellow blue purple colors are in my understanding something that happens to more pure lead. Your fill out problems will probably be solved by adding 2% tin. What you have been doing by putting the spout right up to the spruce is called pressure casting, and can Help with fill out but may cause fins.

[86LG4T5]

Thanks to all the replies. I'm going to try some tin.

[Thecyberguy]

I think you will find the tin will do the trick for you.
I had some zinc contaminated alloy once it, as they said, was like oatmeal......weird looking and lumpy.
Fortunately it was just a few pounds.

[el34]

From what you have said I see no reason to conclude zinc.

Same here. A few drops of muriatic acid on it will bubble if there's any zinc. It's used for swimming pools and available from pool places and Home Depot, usually by the gallon which is a lifetime supply for the whole family.

1% to 2% tin is always a good thing.

[williamwaco]

I have had a couple of batches of zinc contaminated ingots.

About 20 pounds in two batches total.

I was determined not to toss 40 pounds of yet-to-be-cast bullets so I just tried it.

I found that it cast perfect bullets that shot just fine. ( .357 158 gr SWCs )

I do recommend a VERY complete cleaning of the pot after casting this alloy and before refilling it.

[fecmech]

I have had a couple of batches of zinc contaminated ingots.

About 20 pounds in two batches total.

I was determined not to toss 40 pounds of yet-to-be-cast bullets so I just tried it.

+1 I added some tin to mine and they cast just fine.

[leadman]

I don't think you have zinc, just soft lead with little tin in it. For zinc contaminated lead use root killer (copper sulfate) as a flux to remove the zinc. I have tried it and it does work. The copper it leaves also helps harden the lead.
There are a couple of long threads on this.

[bangerjim]

I have intentionally contaminated Pb with up to 5% Zn to actualy disprove the olde "Oh no, a Zn COWW spoiled my whole pot" wive's tale.....and the only thing I see is the weight goes down a tad and fill-out suffers a bit. Just add a little more Sn. Casts and shoots just fine. As usual, use a pre-heated HOT (at casting temp, not warm) mold right off a hotplate!

I have never seen Zn turn "rainbow"! Perfect indication of hot Hot HOT PURE lead. And that color will carry over to your poured cooled ingots with absolurely NO problmes.

As others said, use it....add some Sn.....and cast away!

bangerjim

[el34]

I have intentionally contaminated Pb with up to 5% Zn

I appreciate that jim. Truth expressed in numbers is hard to beat.

[runfiverun]

heck we all probably have gotten some zinc in our casting alloys and never even knew about it.
zinc is soluble in ww alloy and casts normally up to 1.6% it has to be over 2% to show up in enough proportion to become free and form the oatmeal.
"zinc alloy" will generally need a higher heat to cast well.
and it really likes tin [in fact zinc is used to strip tin from alloy being "scrubbed" at a foundry]

[smokesahoy]

Has anyone done testing to see if zn in small amounts could harden lead cheaper than sb? If it's just a matter of putting just enough to harden it without putting too much that fill out suffers it might be a nice cheap alloy.

[CGT80]

I had some lead with zinc in it. It did fizzle with acid. I was able to run it hot with some tin in it and I ended up using a steel rcbs 45 225 rn mold. It filled out the round nose just fine but it would not make sharp edges in my 45 275 SAA mold. I loaded those up for some light 45 colt ammo. I did get the oatmeal on top as well and had to throw some of the mix into my dross can, but I was able to use up most of the alloy.

[Stephen Cohen]

I know some pistol shooters in this country swore by zinc as a hardener in small amounts. I actually cast some 45s today with some old oatmeal sludge I have had for years, was not easy to use but after adding some tin in form of Linotype it was ok. Thank god its all gone though.

[runfiverun]

there is a sticky that splains the use of sulpher to remove zinc somewhere here too.

[bangerjim]

Yes, you can remove Zn (and Sb & SN!) from your melt by using either sulfur (reminds you of your last visit to Hades) or copper sulfate (root killer in the plumbing section of Lowes). I have tried both. Sulfur makes so much mess and stink, I would not recommend it. Sulfate just sizzles and cracks and turns white eventually, but does seem to remove Zn. It also (supposedly) adds a bit of Cu to the mix. I have seen the chemical formula 'splained on here sometime back, but I was horrible at balancing those darned formulas in college!

If you have enough Zn alloyed to make HCl acid boil and fizzz......you got a lot of it in there! At 5%, you almost need a weak microscope or strong lens to see the reaction. But it is there. Zn-free lead just sits there.

banger

[PoisonIvyMagnet]

Copper sulfate can be purchased in two forms, either the white anhydrous or the blue pentahydrate. The white copper sulfate should be dry and safe for use. If you buy the blue colored crystals (which is what I believe you are likely to find at local hardware stores), it should be dried before using, since it contains a good bit of water bonded to the copper sulfate. Just spread it out over tin foil on a cookie sheet, and place into an oven set for 250 degrees F. Heat until the water is driven off and the crystals turn white. Dump it into a dry glass jar and seal, should be ready for use. I've read a number of warnings in other threads about avoiding wet materials into a hot lead pot. Avoid possible injury and only use dry white copper sulfate if you want to remove zinc from your lead pot.

[bangerjim]

I throw the blue crystals into molden lead all the time with no problems. Just let them lay on the top and cook for a minute and they will turn white, then stir in.

There is so little water in there you will never know it! Not like wet sawdust or "washed" WW's!!!!

If you live in a swamp and leave the jar open, the blue ones may attract moisture. But everthing is wet in a swamp!

banger