If lead melts at a lower temp than zinc....

[Lowpower]

I've spent the past 3 hours searching for info about the smelting process regarding the dreaded missed zinc WW that gets into the mix. I've also read about removing zinc with sulfur. Am I missing something? Isn't it possible to run a pot around 640F or so and scoop out any zinc that might have been missed? Please correct me if I'm wrong as I really want to know but if Lead melts at a much lower temp than Zinc doesn't the zinc remain as a solid that can be removed?

Since I'm a beginner at smelting/pouring bullets a friend and mentor came over and together we smelted WW and were able to produce a couple of hundred finished 540 gr bullets and the remainder was poured into a lyman ingot mold. I think I got 14 or so ingots from my pot which I think is only a 20 lb Lyman bottom pour. I'm adding a PID to see if I can further regulate the temps to minimize smelting zinc.

Am I going about this right?

BTW- WW's are not a problem for me and we still have lots of lead around here. I always seem to have 75# of WW in my garage. My main problem is
our temps are outa sight which limits my casting. They always seem to be in the high 90's with 70% humidity. Fall is here so I'm going to try to smelt then cast a lot of bullets this winter so all I will need to do if smelt any new lead I get for next winters pot.

Thanks for any and all help.
Lp

[LAGS]

Lead does melt at a lower temperature than Zinc.
But once lead and Zinc are melted together, and Stired or fluxed, they form an alloy or an Amalgam, and they do not seperate easily.
I did have a batch of lead, that I accidently threw some zinc WW in the pot.
They Melted, but I noticed it before I stirred and fluxed the pot.
I saw some shiny domed bubbles floating on top and was able to scoop most of it out before it got blended in.
But if you have a ton of time, you can heat your lead to 640 degrees and the shut it off and let it cool and the un amalgamated Zinc will come to the top.
Then remelt it to 640 degrees, and carefully skim it off without stirring the mix.
Then repeat the process about 20 or 30 times more and you can get the zinc level down to where it casts good bullets.
To me, it aint worth the trouble.
I would rather spend the time looking for more wheel weights, and use the time to carefully sort them so the same thing doesn't happen again.

[imashooter2]

Yes, if you melt your WW at controlled temperature, the lead will melt and any zinc weights will be solid floating on the surface with the clips, giving you plenty of time to scoop them out.

[jsizemore]

Smelting in a bottom pour pot can lead to a clogged spout in the future. Most smelt in a separate pot over an open flame.

[JSnover]

Smelting in a bottom pour pot can lead to a clogged spout in the future. Most smelt in a separate pot over an open flame.
What he said! Save yourself a lot of headaches and get a separate pot for making ingots.

[RogerDat]

+1 on smelt in one pot cast from another. You want casting pot that only gets nice clean ingots melted in it.

Find a propane fish or turkey fryer cost $10 at garage sale to $40 new at big box or online. Pick up any decent sized, heavy weight steel or cast iron pot at local thrift or salvation army store. Not aluminum, never, not ever! Or purchase a cast iron dutch oven from Harbor Freight cost for a pot $8 to $30. Tel-true makes a thermometer available from amazon that is about $25 and covers the molten lead temp range.

A) your nice bottom pour will stay clean. Not clogging spout and not having crud in bullets is benefit.
B) the fish/turkey fryer melts faster and can do bigger batches. You save time, and large batches are more consistent.
C) for as little as $45 you can gain a much better arrangement. For WW's I think if you monitor the pot stirring and skimming you don't really need the thermometer, really good item to have but most metals you are worried about will float in molten lead.

A small percentage of zinc won't hurt anything. That is one other advantage to a big batch. I think a member banger jim did some testing and found that below 5% zinc it really did not hurt much when it came to casting bullets. A couple of missed WW's in a 75# pot on the fish fryer won't matter as much as it would in a 10 or 20 lb. bottom pour pot worth of lead.

I nip with diagonal cutters to sort out the hard zinc WW's so I have only found 1 floating zinc in about 500# of WW's. I have heard that some folks just melt and skim and for them a phone call at the wrong time that distracts them can allow the zinc to melt in sufficient amount to be a problem. If a zinc WW gets pinned to the bottom of the pot the zinc might be right against heat and melt, but again one or two zinc WW's shouldn't really make a big difference for most uses.

[LAGS]

One or two Zinc WW on your mix, only makes Pond Scum on your next melt.
Skim it off and don't try to keep Fluxing it back in the mix.

[35 Whelen]

Zinc melts at almost 800° F (787°F). I've never even come close to getting alloy that hot when I was smelting. I did over 50 lbs. of WW's yesterday evening and as usual monitor the temperature with a Craftsman digital meter with a temp probe. I just prod, push and stir the mess until I have a fluid mix in the pot, then scoop off all the clips, trash and steel and zinc WW's that have by then floated to the top. After having removed the trash I checked the temperature and it was something a little over 600°.

35W

[bangerjim]

Please.............don't fall into the old wives' tale of "OMG, one zinker spoiled my whole pot!" Not true. If you think it did, please send me all your spoiled Pb!

1-5% Zn will not do any harm. Zn is lighter and raises the surface tension of molten Pb. Adding more Sn will lower it and compensate if you are at casting temp for your mold (use a hotplate!!!) and alloy and are getting poor fills. A bit of Zn will make your boolits harder and a bit lighter, but most try to avoid it.

You do NOT want to go down the road of trying to remove a little Zn using sulfur or CuSO4! Removes all the Sn also and sulfur stinks to high heaven and is toxic. NOT worth all the work! I have tried it. Just sort very well B4.

You should NEVER EVER re-melt anything in your bottom pour pot!!!!!!!!!!!!!!!!!!!!!!!!!! Buy a separate CI pot to use over a turkey fryer or stove to re-melt and flux (3X) weights. All that garbage will end up in your pour spout!!!!!! If you insist on doing small batches like your 20# pot, buy a non-bottom pour electric pot. Most on here re-melt WW's in the hundreds of pounds at a time. I used to use a 70-80# Ci pot over a plumber's furnace (jet engine!) to do all my re-melting of WW's. I quit even messing with weight over 2 years ago due to the high volume of Zn and Fe in the mix. I now mix all my alloys from the metals I want in there.

I know everybody on here seems to try to do everything on the cheeeeeep. But cheeeep is not the best way to do many things, like your re-melting process. Get a separate container to do it in.

Good luck!

bangerjim

[bob208]

cans large cans 1-2 lb. coffee number 10 cans big juice cans. all you can get. then when winter hits start casting and filling cans. don't worry about having too many fill them all and find more. then when it get hot out you just pick out what you need size and lube and shoot. that is what I have been doing for 40 years. just write on the can the caliber and mold number of what is in it.

[williamwaco]

BANGER+1

I spent hours trying to reclaim about 20 pounds of contaminated alloy. Every thing failed except the sulphur. That was so noxious i decided the lead was not worth it. By this time I had almost 40 pounds of it.

I decided to try one more thing. I fluxed it with candle wax and let it stand for 20 minutes. I ignored the oatmeal and started casting bullets. Surprise! They came out perfect. They shot just as good as any others.

I managed to convert 40 lbs of worthless zinc contaminated alloy into about 1500 38s.

[Toymaker]

Yes, you should cast from your bottom pour pot and smelt from another.
Yes, a PID is a wonderful idea.
Sulfur (Flowers of Sulfur) will remove zinc from your alloy, if you can stand the smell and survive the noxious fumes.
Grind some copper sulfate into a fine powder and add it to your alloy. Stir well for a long time. It'll remove zinc but it will increase the hardness of your alloy.
WINTER !! - pick a really cold and windy day. Crank up your pot to about 825° - 850° and stir, stir, stir. You'll get all kinds of cr_p, crud and corruption oatmeal type stuff. It is some lead and lots of tin, antimony and zinc oxidizing and forming dross. Yes, you'd probably like to keep the tin; maybe the antimony, but you can't have it both ways. Skim, skim, skim.

[RogerDat]

I have also heard and read good explanations for why toymaker is right. Anything that would pull the zinc out will also pull the tin out, and probably antimony too. Copper sulfate for sure I read that, along with why the stuff would all bond together.

[bangerjim]

One wiser soul than I on balanced chemical formulas told me CuSO4 will not bond or form any chemical reactions with Sb like it does with Sn. I'll take his word for it. I know it is sure not worth all the hassle to use CuSO4 or S (YUCK!!!) to remove a teeny-weeny bit of Zn from your melt. And you have to add the expensive Sn back in!

Leave the Zn.........cast some bad boys.........and shoot them!

banger

[P Flados]

I am also convinced that a little zinc should normally not be a big deal.

However, I will say that being careful and using good technique is worth the time and effort.

Getting some random small amount of zinc in your lead adds another variable that can mess with you (i.e., how much tin do I need for this batch)

I was sloppy with my last smelt of WWs. I probably came real close to getting more zinc in my lead than I would have been happy with, see

http://castboolits.gunloads.com/showthread.php?286686-Zink-Wheel-Weights-Do-Float-Finally-Took-a-Picture

After my near miss, I am pretty sure I will take the time to do better sorting (bolt cutter chopping most all of the painted WWs) and I will try to get a pool of liquid lead and then add painted WWs in increments while removing clips.

If use your long handled skimming spoon to slowly lower your painted WWs on top of a clean pool of lead, spotting a "floater" is pretty easy. If some zinc WWs are hidden under a bunch of clips, they are hard to spot.

Some WWs that are mostly zinc seem to start dissolving into the lead at well below the pure zinc melt point. When I was scooping zinc out of that last smelt, a bunch of it was partly melted while some still looked "like new".

[35 Whelen]

I'm still not understanding the lengthy discussion how a little zinc is OK, how to remove it, how to detect it using manuals methods, etc., when it is so blatantly simple to avoid it in the first place; don't melt it!

35W

[oldred]

I'm still not understanding the lengthy discussion how a little zinc is OK, how to remove it, how to detect it using manuals methods, etc., when it is so blatantly simple to avoid it in the first place; don't melt it!

35W




Agree on not getting them in there in the first place, while taking the time and effort to nip each piece with side cutters works well for relatively small batches it is very tiresome for large batches so I use another method, the sound test. I have a thick piece of steel, 3/4" thick and about a foot square, so I just drop the weights on this and let them bounce off. If the steel is clean and not rusty there will be no mistaking the sound of the Zinc vs Lead even if the clip hits first, I have so far melted about 250 lbs of wheel weights and sorted out quite a few Zinkers without melting the first one as far as I can tell.

[RogerDat]

One wiser soul than I on balanced chemical formulas told me CuSO4 will not bond or form any chemical reactions with Sb like it does with Sn. I'll take his word for it. I know it is sure not worth all the hassle to use CuSO4 or S (YUCK!!!) to remove a teeny-weeny bit of Zn from your melt. And you have to add the expensive Sn back in!

Leave the Zn.........cast some bad boys.........and shoot them!

banger

I think the the Sn is bonded to the Sb so that the Sn pulls the Sb with it. Easier to avoid than remove, takes about 2 hours to nip test a 5 gallon bucket. Oddly enough about how long it take to watch a movie while doing it.

I guess if I had a 100# in a pot and knew it had zinc contamination I might try to rescue the 100# of lead using CuSO4 or sulpher or whatever would get the zinc level down to manageable levels. 100 lbs. of plain lead is better than what the scrap dealer would give me for my pot load filled with contamination . Now if it was some printers lead in addition to being really bummed I could test the Sb getting reduced theory. Gotta love real world tests.

[bangerjim]

I'm still not understanding the lengthy discussion how a little zinc is OK, how to remove it, how to detect it using manuals methods, etc., when it is so blatantly simple to avoid it in the first place; don't melt it!

35W


Easy to do when processing 50 or so pounds. Sorting is the best way. But when doing many hundreds of pounds like these guys seem to do, sorting is very time consuming and closely controlliing melt temp is the real fail-safe method of catching the zinkers.

Back when I did WW's I tested them by sound and any questionable ones were then tested with diag cutters or HCl acid. My plumber's furnace is not controllable tight enough to allow "temperature" sorting! Most re-melt set-ups that guys use are not either. Sorry, no PID controllers here. Unless someone wants to waste hundreds of $$ on a 4-20 madc modulating gas control valve and analog output controller. Not worth it.....I sell all these things in my engineering firm.

Style and type of sorting is a personal choice. And how much Zn is acceptable to your needs. I personally never cared about 2-3% Zn.

[fredj338]

I have done something sim with contaminated alloy. As Bangerjim notes, a small amount of zinc in a large pot doesn't move the needle. Now 15# of contaminated alloy into a 30# pot does. This happened to me, clogged my Master Cast pot badly. I turned it down to scrape off as much of the floating crud as I could, then added known range scrap to it & turned it up & started fluxing. I manage to get the pot running again. learned lesson, know what the alloy is before adding it to your casting pot.

[RogerDat]

I don't do them all at once typically a couple of buckets over a couple or three days. Call it 150 lbs. or so as a batch. Have done close to 1000 lbs. that way with one WW floating to the surface of the melt.

I don't find it too much trouble for the peace of mind. I'm usually watching TV with a box lid tray in my lap sorting a small batch at a time. By the time I watch a movie or one of those dance contest programs the wife likes a good chunk of a bucket has been sorted.

[LAGS]

If "Dancing With The Stars" was the only thing on TV, I would be sorting weights Too.

[mold maker]

If "Dancing With The Stars" was the only thing on TV, I would be sorting weights Too.

Or counting grains of sand.

[RogerDat]

If "Dancing With The Stars" was the only thing on TV, I would be sorting weights Too.

That and you think you can dance, or most reality shows where nothing kills anything else for food is pretty high on the list of things that make mowing the lawn or other chores look like fun, but my wife is a dancer, I have loading bench she has dance practice room. Sharing the basement for our passions is part of what makes us a couple. I'm just lucky she tolerates my sitting in the living room (with a drop cloth down) and sorting weights while hanging out with her. Not exactly romantic but nice and beats lawn mowing by a good margin.

[LAGS]

No, that is romantic.
You are doing what each of you loves, and though doing different things, you are doing them together.
I always say, It is the differances in the two of us, that should bring out the best in both of us.

[Markbo]

OP I have done the sulfur thing. It is a very unenjoyable experience. Try to avoid it at all costs. It is hard pouring a big bucket of wheel weights into a pot, turning on the fire and trying to control the temperature. I learned my lesson! Try to have a known alloy/ingot melted in your smelt pot and add the WWs a handful at a time so you can firstly control the temperature and stir and remove flotsom as it appears. THEY MUST BE DRY! This an absolute. A non negotiable. If you dont know with certainty, then dont add them!

Secondly i cut a used propane tank about 3/4 the way up (yes I knew for a fact it was clean) from the bottom cut 2 notches out of the top to fit over 2 large C clamps that are on about 4 & 8 o'clock. I can pick it up and pour that way though 98% of the time i ladel it into ingot molds.

Third, do it outside only and expect some smoke & stank. It us the nature of WWs. I would say stay upwind as best you can but humans kind of do that naturally.

Lastly..enjoy it. This is a part of the casting that you can come to appreciate and not hate. It is rewarding turning another man's trash into pretty little ingots. :D

[AllanD]

I've always been mystified by one thing...

When lead is commercially mined and smelted it is INTENTIONALLY mixed with molten zinc.

this is done for a few reasons, first is that natural lead from the ore always contains
some silver as well as traces of gold. and the easiest way to separate the silver from the lead
is to mix the lead with Zinc, you see silver is some 3000times more soluble in zinc than it
is in lead... and in commercial lead mining it is the silver that pays all the bills!

in most operations they could throw away the lead and still be safely profitable on the silver
and copper they extract from the lead.... the lead is pure profit!

Unfortunately I don't know how they separate the zinc from the lead in the industrial process

I assume that sulfur and chlorine are involved.. silver and copper both have a strong affinity
for sulfur and Zinc wants to bond with chlorine...

AD

[BNE]

For what it is worth, smelting in a bottom pour pot is not terrible. Yes, you run the risk of clogging your spout. I bought a small gravy dipper and pull the lead from the top. I then used a wire brush to brush the empty pot down after the smelting session. I also pulled the rod that seals the spout and lightly sanded it with some fine sandpaper.

I now have two other pots I can use for smelting and one for casting. BUT getting started casting can be fairly expensive. Don't let the lack of a dedicated smelting pot stop you from smelting.

One trick that really helped me is to keep one of those "wind proof" lighters close by. The spout is one of the last things to heat up when you are starting a casting or smelting session. heat it with the lighter and you will be in business sooner.

enjoy

[Nose Dive]

Agree with RodgerDat... smelt in one pot,,,,make ingots...cast from another pour pot....using your clean, nice alloyed ingots.

And, when in doubt about ZINC in my smelt pot, ( always am) I stay down around 600 and flux like heck, scrap bottom, sides, and remove garbage... If you keep your smelt temp down, (600), the heavier stuff can be screened out and removed and you avoid alloying with things you don't like. I see guys on UTUBE smelting with a propane cooker and you can barely hear them talk because the darn flame on the burner it 'blazing' like a jet engine!! JEEZZZZ... cool it down fellas!!! And too,,,I am alwasy concerned about water in the smelt...so...LOW FLAME...SLOWLY....FLUX....STIR.....it always takes me about an hour to get the smelt melted....Yea...I know...'old and slow' but never had a pot full of lead blow up on me.... and because all my smelt it 'trash, corruption, water washed waste', I flux alot, sawdust /sulfur,,,some times some borax....

Cool it off...slow it down...smelt anything you give me....

Nose Dive

Cheap, Fast, Good. Kindly pick two.

[Hickory]

I have learned that it's not necessary to sort the zinc out of wheel weights when melting them down in large pots.
I start out with about 15-20 lbs. of lead ingots at a high temperature. I add small amounts of WW by hand, one hand full at a time. This is not more then 15 or 20 WW' s depending on the size.
They will melt in short order, 20 to 30 seconds. You will have plenty of time to skim the metal clips with a slotted ladle.
If any wheel weights are still flooding I remove them and set them aside as I am 99.999% sure that they are zinc.
After every 6-8 handfuls of WW I flux the mix. When doing it in this manner, you need to be alert all the time.
When the pot gets too full some of the melt is poured into ingot moulds.