Casting zinc?

[Rick Courtright]

Hi,

As many of you have already experienced, a bucket of wheelweights today usually includes a lot of zinc weights. I still have enough old school "lead" weights to last a couple more casting sessions, then it'll be time to start "sorting."

Now, I've heard and read every kind of story from "a single zinc wheelweight will ruin your whole pot of metal" to "a couple of zinc weights is no big deal."

So what REALLY happens w/ zinc in the pot? Do the molds not fill out, are there more bubbles than lead, are the bullets odd weights cuz the zinc doesn't mix well, or what?

Rick C

 

[96/44]

The Zinc does melt at a higher temp, and is lighter so it will usually float up to the top of the pot with the clips and other junk when you are smelting them. I did have a couple get melted in one batch, when I forgot about the smelting pot for a bit too long. The lead got kind of a sandy/chunky texture and didn't flow out of the spigot that well, but the bullets turned out decent, and were a couple of grains lighter than normal. They seemed to shoot just fine.

 

[GP100man]

Rick C

Some casters cast with up to 2% for boolits in the hi 20-low30 bhn but these are strictly target boolits .

Zinc will titen lead to the point of uncastability at 6% .

As stated stay with the smelter & start skimmin clips when ya can & all should be well ,but I still sort(with side cutters) em out !!

If you suspect zinc take a drop of mueritic acid & drop it on suspect alloy if zinc is present the drop of acid will dance for ya !(All safety garb applies)

Some have claimed that fluxing with sulphur will remove zinc ,but I`ve not had to try YET!!

Here`s a pic of some I`ve sorted in the past ,but no means is it a complete compilation of info on the different ones out there !! As ya can see some have Zn on em & some have nadda !!

 

[Olsherm]

I just melt them all and pick out whatever floats,flux and skim good,then cast and shoot up a storm. LOTS OF FUN,ALLSHOOT FINE.Pure lead even works for me coated with Lee Liquid Alox.Sometimes I mix 1/2 pure lead and 1/2 wheelweights??? Works for me.

 

[gunzo]

I suspected I had some zinc in my buckets of weights, so I looked up the melting points of lead & zink. Bought a casting thermometer.

Pure lead-545 deg
Alloyed lead- up to 650 deg
Zinc-787 deg

Haven't tried it yet, but thinking that if I keep my temps below about 700 that I'll melt what I can use & throw out the rest.

Ya think this idea has merit?

 

[gramps]

gunzo et al this has been discussed over on the Castboolits forum. Yes you are right. Keep the temp between 650-700 and the zinc will skim off the top still solid. Good luck and happy casting!
gramps

 

[kooz]

I suspected I had some zinc in my buckets of weights, so I looked up the melting points of lead & zink. Bought a casting thermometer.

Pure lead-545 deg
Alloyed lead- up to 650 deg
Zinc-787 deg

Haven't tried it yet, but thinking that if I keep my temps below about 700 that I'll melt what I can use & throw out the rest.

Ya think this idea has merit?

Yup, this is how I do it, use a thermometer and keep the melt under 700 and the zink will just float to the top with the rest of the clips and other junk.

 

[clintsfolly]

Do not throw the clips ,zinc and steel out! Save then and sell at the scrap yard. The last batch I sold got me $.10 per lbs and had just over 300lbs and It pays for the propane to clean the WW's Have FunClint

 

[Bucks Owin]

Rick C

Some casters cast with up to 2% for boolits in the hi 20-low30 bhn but these are strictly target boolits .

Zinc will titen lead to the point of uncastability at 6% .

Yes, contamination with zinc can raise hades with casting a pretty looking bullet!
I may be all wet, but it "seems" like when I stir in a good sized gob of pine pitch that a troublesome batch of alloy sometimes begins to behave again in the mold... :? Makes a nasty looking smoking black scum on top of the mix for awhile, but what comes out the spout seems improved...
(At least it smells good.. :lol

FWIW...