Lead and Zinc?
 

As you guys know I am new to bullet casting. I just purchased a bunch of WW ingots on-line for a pretty good price. They look good to me, but as I said I'm new so what do I know.

When I melt these down to make bullets what should I look for as far as Zinc or other unwanteds?

Thanks

Re: Lead and Zinc?
 

Zinc has a higher melting point (but not too much higher) so when you've got a good base of melted lead, anything that doesn't melt pretty quick, remove immediately. It tends to float as do the clips so it's not too difficult but if you let it sit, it will melt in your alloy.

http://castboolits.gunloads.com/showthread.php?t=66241

WA state outlawed WW lead, pretty bummed... they're all zinc now...l

Re: Lead and Zinc?
 

The only thing is that these are already ingots so it will depend on the original owner if he had zinc mixed in and ran a hot enough temp to melt it. You pretty much won't know until you pour some boolits. I think, I've never had a zinc problem before.

Re: Lead and Zinc?
 

ah, thought you meant original WW's, they are already melted into ingots?

doubtful you're gonna separate those without losing the antimony also.

Re: Lead and Zinc?
 

You could remelt and flux the top with a lot of sawdust which will remove a lot of the impurities. Molten zinc is apparently highly toxic when heated to it's vapor point and is quite a bit higher than the ww melt temp. However; fluxing with sawdust will remove other impurities that can affect the overall quality of the finished cast bullet.

Re: Lead and Zinc?
 

If there,s zinc in the mix it will have a dull and wrinkled look to it as it will have a blue and purple color to it on top of the lead pot. I found that out one time myself. Thought i had lead but did not. I was able to blend new lead in and it did break up the PPM of the zinc. It will take a crap load of lead to do it. You can also break the zinc ingot and if it has a grain structure to it its zinc, lead has no grain structure to it. I will see if i can find it and post a pick of it.

Re: Lead and Zinc?
 

yep. and once alloyed it is incredibly difficult to separate it.

Keep your pot temp at around 660 degrees and no hotter. Pure lead melts at that temp and all the good metals that make a good lead alloy melt at a lower temp. all the stuff that ruins your mix melts at more than 700 degrees.

So maintain a 650-660 degree pot and flux often. Keep the floaties skimmed off.

I made my own flux when i casted. Home made bullet lube and sawdust, mixed into an even slurry and let set to harden in a pan. Then cut into cubes about 1/2"X1/2"

Re: Lead and Zinc?
 

interesting thread. I do lots of electronics and plumbing and repair work on old tracotrs and large equipment.. I do soldering daily... i find this thread interesting as I work around different solder alloys alot.

zinc will wet / stick to aluminum.. but lead won't. not sure if that helps anyone.. :)

Re: Lead and Zinc?
 

Its not the best pick but you can see that zinc has a grain structer to it.

Re: Lead and Zinc?
 

That aluminum trick is how i used to get the zinc outta my mix back when i first started casting.

Aluminum melts at a much higher temp than any lead compatible alloy but zinc will stick to it and lead wont. so it makes a good catch for unwanted zinc.

Re: Lead and Zinc?
 

That I did not know. Good info to have.

Re: Lead and Zinc?
 

I guess if you ran the pot in between lead and zinc temps, you could just scrape off the dross that forms (the oatmeal), and add antimony afterwards if desired? the antimony has a 1100' or so melting temp correct? Better to have softer lead than hard lead with zinc contaminating it.

Re: Lead and Zinc?
 

Update:

I cast about 200 10MM bullets last night and everything went great. Clean, full mold, no sags, nothing that would indicate Zinc in the mix.

I ordered more.

Thanks for all your help.

Re: Lead and Zinc?
 

Ummmmmm.... Where are the pics? :tapfoot: