What does zinc do that makes it so bad.

[Ball Caster]

I have read a lot of stuff about removing zinc from lead, not mixing zinc with lead when casting bullets; but I have not read why.

What does zinc in the lead alloy do to the bullet or the barrel etc?:

[454PB]

Small amounts aren't too harmful, but in higher concentrations Zinc makes it very hard to get fully filled out casting. Zinc also lowers the boolit weight.

[curator]

Zinc added to a lead alloy makes the melted metal go from reasonably liquid (sort of like mercury) to sludge. Imagine trying to pour oatmeal into your bullet mould. That's what Zinc in just about any amount will do to your lead for bullet casting. Better to not allow it into your melt than try methods to remove it. Zinc does melt at a higher temperature than pure lead or lead/antimony alloy allowing for it to be skimmed off unmelted if your temperature does not go above about 800 degrees fahrenheit. A lead thermometer is your friend here.

[GabbyM]

If you are trying to make the perfect hunting bullet. One that expands without breaking up to loose weight. Zinc sucks. Copper is also looked upon as a contaminated but I add it to my bullets.
If you have zinc contamination it can be removed. We have threads on this here.

[jonp]

GabbyM: You add copper intentionally to your melt?

[GabbyM]

GabbyM: You add copper intentionally to your melt?

Sure do. Helps keep rifle bullets from blowing apart upon impact. Toughens the lead. If you flux wheel weights with copper sulfate sold at stores for pond and pool maintenance. The sulfur will remove zinc and the copper will replace the tin and zinc in the WW. Roto Metals #3 Babbitt has 8% Cu and is plenty of Cu when used to add 1% tin to WW metal. .03% Cu is generally all I add.

Here is a recent thread on copper alloying.
http://castboolits.gunloads.com/showthread.php?172475-High-Copper-Alloys-Lets-discuss-this-further

[country gent]

ZInc in lead has several side effects that dont relateto good casting. Zinc raises the melting point of the allow meaning the pot and mould have to be run hotter to get good fill out and flow. Zinc lead mixes also befome more pourous making consistancy harder to maintain. Zinc also creates harder more brittle bullets. Zinc will also being a less dense material lower bullets wieght for a given mould. Years ago some ipsic competitors were shooting zinc bullets for the lighter wieght and lowered recoil.

[bubba.50]

I seem to recall reading on here somewhere that some company was makin' 22lr ammo with zinc bullets. anybody know what i'm talkin' about or is this another example of me bein' confused by websites?

[JonB_in_Glencoe]

I did an experiment where I added precisely 1% Zinc to my Rifle alloy (94-3-3).
It does add a small amount of hardness, about one point air cooled and two points heat treated.
I didn't have any issue with casting, although I did have the pot temp a little hotter than I normally would for that alloy (without the zinc).

[bangerjim]

Yes, Zn in small amounts, is not bad. It will make your mix slightly harder, lighter, and harder to cast. There is really no empirical data on using Zn for hardening like there is for Sb. So why mess with it. Sb is cheap. Zn raises the surface tension of the alloy and can get in the way of good cavity fill-out. Adding more Sn will lower it back down, but it gets into a vicious cycle of metal, temp, hardness, and cost! As you know, Sn is very expensive these days!!!!!!!

I added 1,2,3,4 & 5% Zn to experimental batches a couple years ago and saw no real degradation, other than having to crank up the pour temp and/or add more Sn. And boolits got slightly incrementally lighter per the % of Zn in the ratio of alloy.

But Zn does not really have a place in what we NORMALLY do with casting boolits. I personally would NOT recommend using it in place of Sb to ry to get harder Pb.

I would recommend to do all you can to avoid large percentages of Zn in casting your boolits. That is accomplished with a watchful eye when sorting and re-melting COWW's, for those that still mess with those dirty filthy things. I quit messing with WW's over 2 years ago.

And, yes, Cu adds "toughness" not hardness to your mix. I use no more than 2% for certain alloy pours. I do NOT consider Cu as a contaminant as Zn is.

bangerjim

[jonp]

Sure do. Helps keep rifle bullets from blowing apart upon impact. Toughens the lead. If you flux wheel weights with copper sulfate sold at stores for pond and pool maintenance. The sulfur will remove zinc and the copper will replace the tin and zinc in the WW. Roto Metals #3 Babbitt has 8% Cu and is plenty of Cu when used to add 1% tin to WW metal. .03% Cu is generally all I add.

Here is a recent thread on copper alloying.
http://castboolits.gunloads.com/showthread.php?172475-High-Copper-Alloys-Lets-discuss-this-further

Thanks for the post. I can't believe that I've missed this.

[bangerjim]

Sure do. Helps keep rifle bullets from blowing apart upon impact. Toughens the lead. If you flux wheel weights with copper sulfate sold at stores for pond and pool maintenance. The sulfur will remove zinc and the copper will replace the tin and zinc in the WW. Roto Metals #3 Babbitt has 8% Cu and is plenty of Cu when used to add 1% tin to WW metal. .03% Cu is generally all I add.

Here is a recent thread on copper alloying.
http://castboolits.gunloads.com/showthread.php?172475-High-Copper-Alloys-Lets-discuss-this-further


One of the drawbacks of using CuSO4 (root killer in the plumbing department) is it DOES remove Zn, but it also strips all the Sn out....something we really want! Granted COWW's have only 0.5% Sn, but that is just more you have to add back in....at over $10/#!!!

Best bet is what I do is add an alloy that already has the Cu in it ( like copper Babbitt metal). Then you preserve the Sn.

Stripping out Zn has it's drawbacks (removing Sn).

I have played extensively with both sulfur and CuSO4 with Zn contaminations. Kinda a PITA. Definitely NOT sulfur!!!!!!!!! SO2 is toxic and stinks to high heaven.

banger

[jonp]

Sure do. Helps keep rifle bullets from blowing apart upon impact. Toughens the lead. If you flux wheel weights with copper sulfate sold at stores for pond and pool maintenance. The sulfur will remove zinc and the copper will replace the tin and zinc in the WW. Roto Metals #3 Babbitt has 8% Cu and is plenty of Cu when used to add 1% tin to WW metal. .03% Cu is generally all I add.

Here is a recent thread on copper alloying.
http://castboolits.gunloads.com/showthread.php?172475-High-Copper-Alloys-Lets-discuss-this-further

I don't want to turn this thread from zinc to copper but do you use an acid flux as mentioned in that thread?

[GabbyM]

I don't want to turn this thread from zinc to copper but do you use an acid flux as mentioned in that thread?

Never used a liquid acid. CuSO4 would be acidic right?

As for loosing tin in wheel weights. The scrap ww I've had over the last ten years never showed much sign of tin. Not near as hard as a BHN#12 commonly given either. They all have zinc anymore as it gets recycled in at some level I suspect. Or perhaps I've just been unlucky. Couple batches of WW is not much of a sample. But if it has that oatmeal in it I call it zinc. CuSO4 cleans it up. For the smoke. Well I've been known to use old black motor oil as flux when melting down WW scrap. Probably not to be done in town. What I have for this year is a bunch of pure lead that I'll be adding super hard antimony and Babbitt to. I need to get some scrap lead shot for arsenic to help heat treatment. Plug the numbers into an alloy calculator.

[bangerjim]

NEVER use a liquid or gel acid as a flux for re-melting or casting!!!!!!

Pine sawdust 3X is the best and what most of us now use.

Acid will eat up your pot, make a mess, cause potential personal damage to your body, and send an invitation to the TF! What a wonderful combo.......hot acid and molten lead flying in the air towards you at blinding speeds!

CUSO4 is not an acid in it's crystalline form. It does create a somewhat lower acidic pH (less than 7) when combined with water. If you want the balanced chemistry formulas of this, use your leeeeeetle search engine called Google! It is a dry (sort of) crystalline chemical used to kill algae in ponds and roots in sewer and septic systems. It is in the form of blue crystals in the bottle but when you put it in the pot, it "cooks" and the entrained moisture comes out and the crystals turn white/gray. You get it in the plumbing department of big boxes. I use is as algae control in my swimming pool in the summer. A little goes a long way.

Still not worth all the hassle and mess to try to add Cu to you mix.

Just buy/use a Cu-bearing alloy to sweeten..........and flux 3X with pine sawdust.

banger

[GabbyM]

http://castboolits.gunloads.com/showthread.php?105952-Lead-alloy-calculators
Above is the lead calculator I use.
Copper is a grain refiner as is sulfur and arsenic. All enable our alloys to react to heat treatment.
Here is a good article by Wiljen on grain refiners. He actually understands this stuff. I just follow recopies. http://www.lasc.us/WiljenArsenic.htm

[Nose Dive]

Mmmm.. I am an 'old hand' at adding powder sulfur to my smelt pot. I 'normally' do it as I smelt a lot of trash stuff....I really don't know what is truly the mix in my smelt pot as things aren't 'graded' at the junk yard, dump, and metal scrap yards I frequent....Now,, Copper sulfate.... Mmmm I GONNA TRY IT! I can get some for free and add a bit to my next smelt. Maybe a hand full in with my sawdust and let's see what happens.

Will segregate this blend and see if she performs better than my old 'junk yard' alloy ingots.

Will let you all know.

Nose Dive.

Cheap, Fast, Good. Kinldy pick two.

[lwknight]

Zinc contaminated lead still makes pretty good tractor weights but impossible to cast bullets with.
Even if you skim off the sludge that keeps coming back the mix is just too brittle for boolits unless you actually want something really hard and brittle. They come out soft but in a few days will be entirely hard.

Basically, I'm in the zinc is bad crowd.

[Dakooz]

Good info. here. Pretty sure I have some contaminated lead. Based on what I've read it appears I need to invest in a proper thermometer and do some skimming.

[GabbyM]

Good info. here. Pretty sure I have some contaminated lead. Based on what I've read it appears I need to invest in a proper thermometer and do some skimming.

There are some old threads here about cleaning zinc from lead. I've read them a couple years ago but the CRS has he best of me. Search should turn them up. CuSo4 will work to some extent then leave behind copper. I do wear a respirator when burning the sulfur. That's a peace of kit I have around here anyway. Use them when combining beans. Because a friend of mine's dad died from a lung disease caused by bean dust. Air conditioner and fans have not worked on our old combine since before I laid eyes on it. Plus I do mold remediation and bio forensic cleanup.

Way I set up to add CuSo4 is simple . Use an electric fan outside. Blow it across where you will stand not on the pot. Get a transfer shovel. That's the square nose. Suppose though any old shovel would work. Point is to be standing way back in the clean air. Then I use an old weed hook to stir the pot. Maybe 4 1/2 foot long. Simple goal is to stand way back to you stay within the fans blown area. Past that you need to setup where wind will not blow smoke around in front of your fan.
It is somewhat fraught with danger. I like having he copper in my lead so have been known to dump in zinc WW to get the ball rolling. But like Pooper discovered. It's better to just exchange the tin in WW for Cu content.

Last time I hade a bunch of Zn contaminated lead was a few years back before I knew how to clean it. I just took it back into the scrap yard where I'd bought it and exchanged it pound for pound with different lead. It had been a fork truck counter weight.