Sawdust works to remove zinc in your molten lead mix.

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Kryogen

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Got a full pot of WW too hot over a propane flame, and some zinc weights melted into the mix.

Usually, on clean lead, when adding sawdust, it will just burn, and turn black, and form a powder on top.

On that batch, adding sawdust would make floating oatmeal that I could skim off. So I kept adding sawdust and stirring it in until I got only powder on top. Took quite a bit of sawdust, but just letting you know that it works to remove the zinc if you got some mixed in by accident. Way easier not to have zinc melted though.

Another thing I do, is add enough WW to the mix to get the lead back into "solidus" state(kind of like a slush). Then, heating the pot, as soon as the lead turns into liquidus(truly molten), and the rest of the impurities (includinc zinc) are still in solidus state, I skim all the clips, zinc weights and zinc contaminants off. Gone.

`Then add sawdust, nothing but carbon, good to go.

Just a trick.
 
Sorry to tell you, but you still have zinc in there. Sawdust will not remove it. Copper II sulfate will help remove some as well as adding fine strands of copper wire. But even then you will not remove it all.

Set it aside and clearly mark it, see how it casts and hope for the best.
 
ive heard sulfur will bring it to the top but ive never let zinc get into WW lead one time a ice cream scooper I was using for scraping dros well I left it in some pure lead and it melted in I also got zinc poisoning not fun but I did find a way to make zinc cast good a small bit of copper in the mix im not going to say what to add to get the copper in there though
 
maked the ingots with an X so I know.
will be able to take care of those.
I,ve read about sulphur, will try it.
But no matter what you say, I got a ####load out with sawdust and cooling/melting skimming cycle, I would say it's almost all gone.
 
Spawn-Inc said:
Sorry to tell you, but you still have zinc in there. Sawdust will not remove it.
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Might want to back this with some scientific litterature, or personal experience, otherwise it's just your opinion, and it's not worth much to the debate, really.

What I am telling you is that I have melted and fluxed 700 pounds of lead WW, and every time sawdust fluxing would only dust on top. And with the zinc contamination, fluxing removed massiva amounts of solids, and after all that, it dusted like it used to do. Now, to say that I did not remove zinc contamination that way, you will have to give more information that just your opinion.

http://www.sixguns.com/crew/simplefluxing.htm
"
Of particular interest to the bullet caster are calcium, aluminum and zinc -- all of which are difficult to reduce and all of which cause casting problems if present in any significant amount (they muck up the surface tension of the alloy and prevent the alloy from filling out the mould properly). As the sawdust chars, it can be thought of as a kind of activated carbon. Both the lignins of the original sawdust and the oxygenated sites of the activated carbon are very effective at binding metal ions like calcium, aluminum and zinc. Thus, the advantage of sawdust is that it does both jobs, returning the tin to the melt and removing the problematic impurities. Sawdust has the added benefit of being free."
 
Kryogen said:
Might want to back this with some scientific litterature, or personal experience, otherwise it's just your opinion, and it's not worth much to the debate, really.

What I am telling you is that I have melted and fluxed 700 pounds of lead WW, and every time sawdust fluxing would only dust on top. And with the zinc contamination, fluxing removed massiva amounts of solids, and after all that, it dusted like it used to do. Now, to say that I did not remove zinc contamination that way, you will have to give more information that just your opinion.

http://www.sixguns.com/crew/simplefluxing.htm
"
Of particular interest to the bullet caster are calcium, aluminum and zinc -- all of which are difficult to reduce and all of which cause casting problems if present in any significant amount (they muck up the surface tension of the alloy and prevent the alloy from filling out the mould properly). As the sawdust chars, it can be thought of as a kind of activated carbon. Both the lignins of the original sawdust and the oxygenated sites of the activated carbon are very effective at binding metal ions like calcium, aluminum and zinc. Thus, the advantage of sawdust is that it does both jobs, returning the tin to the melt and removing the problematic impurities. Sawdust has the added benefit of being free."
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Any perceived difference in effectiveness between hardwood sawdust and softwood sawdust?
 
Kryogen said:
Might want to back this with some scientific litterature, or personal experience, otherwise it's just your opinion, and it's not worth much to the debate, really.

What I am telling you is that I have melted and fluxed 700 pounds of lead WW, and every time sawdust fluxing would only dust on top. And with the zinc contamination, fluxing removed massiva amounts of solids, and after all that, it dusted like it used to do. Now, to say that I did not remove zinc contamination that way, you will have to give more information that just your opinion.

http://www.sixguns.com/crew/simplefluxing.htm
"
Of particular interest to the bullet caster are calcium, aluminum and zinc -- all of which are difficult to reduce and all of which cause casting problems if present in any significant amount (they muck up the surface tension of the alloy and prevent the alloy from filling out the mould properly). As the sawdust chars, it can be thought of as a kind of activated carbon. Both the lignins of the original sawdust and the oxygenated sites of the activated carbon are very effective at binding metal ions like calcium, aluminum and zinc. Thus, the advantage of sawdust is that it does both jobs, returning the tin to the melt and removing the problematic impurities. Sawdust has the added benefit of being free."
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from experience in refining by melting, charcoal works just as well... Zinc will also drag some other metals out of the melt.
 
Kryogen said:
Got a full pot of WW too hot over a propane flame, and some zinc weights melted into the mix.

Usually, on clean lead, when adding sawdust, it will just burn, and turn black, and form a powder on top.

On that batch, adding sawdust would make floating oatmeal that I could skim off. So I kept adding sawdust and stirring it in until I got only powder on top. Took quite a bit of sawdust, but just letting you know that it works to remove the zinc if you got some mixed in by accident. Way easier not to have zinc melted though.

Another thing I do, is add enough WW to the mix to get the lead back into "solidus" state(kind of like a slush). Then, heating the pot, as soon as the lead turns into liquidus(truly molten), and the rest of the impurities (includinc zinc) are still in solidus state, I skim all the clips, zinc weights and zinc contaminants off. Gone.

`Then add sawdust, nothing but carbon, good to go.

Just a trick.
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That's an interesting trick, Kryogen.

I never knew that sawdust would do that.

I hope that those ingots are pure lead now and melt into some nice bullets for you.
 
Will try those when I get my lee lead melter (BO).
Might try to flux with sulphur if they still don't cast well enough.
So far they poured nicely into ingots.....
 
I've "smelted" over two tons of wheelweight, and I've yet to melt any zinc into my mix - and I don't even try to separate the zinc ahead of time. No thermometers, nothing, just attentiveness and care.

I just don't get it.

To be fair though - s$$t happens. If it happened to me, that mix would go to the recycler. I've read the threads on removing zinc, and the methods are dubious at best, dirty and even toxic at worst.
 
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Kryogen said:
maked the ingots with an X so I know.
will be able to take care of those.
I,ve read about sulphur, will try it.
But no matter what you say, I got a ####load out with sawdust and cooling/melting skimming cycle, I would say it's almost all gone.
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it will still keep floating up trust me been there done that(read above) I used that mix to make sinkers after pouring about 15 lb into scrap
 
Kryogen said:
what kind, and where do you get it? charcoal bricks that you just crush?
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Any kind of charcoal. I use lump charcoal. Last time I checked, home depot sold bbq charcoal. The zinc is more attracted to the carbon in the charcoal than the lead, so it binds to the zinc, lightens the density, and the charcoal/zinc floats to the top. You have to mix the charcoal/sawdust in thoroughly to get the zinc out however. Sawdust works too, as it converts in the heat, but for the amount I was doing, sawdust in those quantities was a little bit hard for me to easily come by, so I just buy bags of charcoal.
Lead is great for separating precious metals from iron, and zinc is highly attracted to the precious metals in molten state. The iron is melted, and cooled and removed as a dross/slag. Then, an excess of zinc is put into the lead melt, either causing the precious metals to float, or sink to the bottom, depending on densities. The ones that float are skimmed off, then the lead is poured into a separate vessel, and sawdust added to recover the zinc for reuse after burning the carbon out of the zinc.
 
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when melting down wheel weights keep your temperature as low as possible, just high enough to melt the alloy and not the Zinc wheel weights. I had some Zinc fouled alloy and found if the temperature was 600f or so I got the "Oatmeal" on top of the alloy, easily removed then but I still had to mix it with clean alloy for best result's

Incidentally, my Brother was showing me his new Costco installed tires on his 1 ton Super Duty, the ww were marked Zn.
 
I got zinc in because I got sick of paying attention and just cooked the heat on. Bottom got way too hot, and top didnt melt, because it was resting on all those clips.
Bottom line, melt a reasonable quantity only at once.

I only have 35 pounds that I might have contaminated on over 700 pounds so it,s not too bad, and like I said, by getting the lead molten, and not the rest, I skimmed most zinc out, and then fluxing, it was quite nice after that, poured #1.

Will report when I cast bullets, I'll take those ingots first
 
One other note on zinc.

First time melting wheel weights I was inexperienced (have since done several batches with a true veteran to train me), anyway, I melted everything that would melt, which must have included zinc. The veteran explained what I did wrong, and that my first batch would probably not shoot well.

Well, bullets from that batch actually shot just fine, and accounted for a nice moose last year, taken with 360 grain bullets from a 45-70.

So, I wouldn't throw out your 35 lbs of ingots until you have tested to see if the stuff will shoot or not...
 
I am certainly not throwing that away as it poured perfectly fine, and I am way too stubborn to throw that away, anyway. I would fix it.
 
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