Salvaging Zinc Contaminated WW ingots

[Republic of Alberta]

I am new to casting, so as a newbie I made the mistake of melting my WW without a thermometer and got some Zinc melted in there too. I did a search here and found it was suggested I could bring my pot down to 650 and skim off some of the zinc. Being that I have about 50lbs of bad alloy I would like to save it if I can. Obviously I will get a thermometer before I do this:grin:

My question is if I do this will I still be able to make good heat treated bullets? I intend to load some hard .710 round balls in a 12g as well as 30cal for general shooting. The round balls are meant to be super hard penetrators that won't break up. Will having some Zinc (what ever I cannot skim out) cause my round balls to be brittle? Will I be able to fill out a 30cal mould with out a problem?

Anyone save a screw up like this before?

[STP]

I can`t speak to how it would effect your RB`s but I can tell you that having cast cores with a tin/zinc alloy (in increasing percentages of zinc) on request that you have a chore ahead of you.
By the time I got to the upper percentages of zinc, the nozzle would not close fully, and the remnants left behind on the pot walls was (is) a total mess.
I tried 20lbs of my ww alloy thru it afterwards at maximum temperature, fluxed and skimmed, then poured it out, yet the zinc remains stubbornly adhereing to the pot walls...rather like cake frosting that will not budge.
Anyone ever drill out the rivets from a RCBS 20lb Pro-Melt to remove the pot liner from the furnace? Surely not a warranty issue...?
What a PITA.

Do you have a similar "film" left behind?
Also, do your RB`s have a "fuzzy" surface finish to them?

[Republic of Alberta]

I did not have any film left on my pot or spoon I was using a 2burner Colman stove so I may have had the them so hot it was not an issue? I did realize my mistake at the end when I turned the stove down a bit and started pulling a few Zinc WW out.

As a test I left a bit of lead in the pot turned it up to where I had it before and threw a Zinc one in to See what would happen, It melted and did not make a mess. I tossed that test bit of course!


I don't actually have any moulds yet they are on the way from Lyman so I cannot play to see what the alloy will do. I am going to try to clean up my ingots before I actually cast a ball, seeing as I am new I don't have experience to help me when things go wrong.

[Pepe Ray]

Hold up there.
I dont cast round ball BUT if I did and had a supply of zink contaminated lead ,I'd try it in the round ball mold.
1. Your contamination is probably only enough to screw up a standard boolet which requires SHARP corners and grooves.
2. this is not the case w/RB
It may be that your biggest problem will be segregating your stock and marking it. I know that salvaging it per the skimming technique is a B*%^h.
Don't do anything till we get some more advice.
Pepe Ray

[Lloyd Smale]

Dont know how bad your batch is but ive got slightly contaminated batches to cast buy adding about 5-8 percent tin to it and cranking the pot wide open and casting as fast as the mold will allow.

[mroliver77]

As Lloyed has said I have ran a very hot pot with extra tin and came up with shootable boolits. I use saw dust and oil as a flux for this type of casting and flux often. The problem as somebody else stated is to not let the contaminated alloy contaminate more of your stash. Just a little zince stuck to the sides of your pot will contaminate new batches of alloy. I sand blasted my pot clean and started over after this.

[randyrat]

I've never run into a bad batch of Alloy,i'm very carefull as not to allow any zink WWs in the mix and watch the temp. I've thought about what to try if/when it happens to me. I would flux with Liquid alox, wax and some saw dust then raise and lower the temp and skim a lot. The liquid alox seems to work for fluxing even better than wax, Smoke,smoke and more smoke but the alloy comes out real nice an clean. Notice i said TRY.... You may end up with pile of, well you know. There are some threads that talk about fluxing and zink contamination. Also hold on to your boots not everybody has chimmed in yet on this.

[leftiye]

I recently purchased 100 lbs of badly contaminated linotype. See thread - "Mush (you huskies?)". Short version, remelt alloy just enough to melt part of the alloy. The zinc will separate and form a nasty sludge that almost appears to be foam. If you can control temp, keep it around the usual melting point of your alloy. Mine was linotype which melts at 450 degrees F. I kept the mess at about 600 degrees.

And the solution- spoon out the sludge/foam and throw it out. Mine could be recombined with high enough heat and fluxing extensively, but it wouldn't cast well at all because of continual re-separation as STP said. I lost eventually about 60% of the original metal. It keeps coming out in sucessive remelts.

[cbrick]

leftiye nailed it pretty well. As you begin melting your contaminated WW alloy, the different components in the alloy having different melting points will melt at different times. Without stirring allow the temp to come up to 600 degrees or a tad under, Zinc (and your antimony) will form on the surface. It can be skimmed off at this point but you will lose a good percentage of your antimony also. You will never get it all out though and it takes a very small percentage of Zinc to ruin the alloy for bullet casting.

The suggestion of using contaminated alloy for round balls might be a good idea but that's just a thought, I've never tried it.

Unless your hard pressed to come up with more WW I would just toss it. Hardly seems worth the effort but then I'm sitting on about 700 pounds of cleaned up WW ingots so I guess that's easy for me to say.

Keep us posted on what you come up with, perhaps we can all learn something here.

Rick

[VTDW]

You said when you turned down the temp a bit some Zink WW surfaced?? Are you SURE your melt is contaminated?

Dave

[Republic of Alberta]

I think I must have only got a little Zinc in my melt, judging from what I have researched here so far. A bit of a "galvanized" look to the ingots on the sides and bottoms little on the top but not to terribly bad (my last batch where I pulled out Zn does not have the same look)and no really bad mess in the pot. My pot is enamel coated so maybe things don't stick to it badly?


Anyways this is what I might do. I will get a thermometer, remelt most of my ingots, throw in some sawdust, flux, let it sit, skim and pour ingots. I will also keep a few "contaminated" ingots just to try in the Round ball mould. Who knows they may make a really hard and tough ball. Could be the next "new thing"....or not.... no probably not.:)

[leftiye]

Skim BEFORE you do any stirring or fluxing! If you stir, some of the crud will be mixed back in.........

[Blackhawk Convertable]

If you are making ingots, you don't need a thermometer. Just bring the WW's to melting temp and skim. I'm guessing that it would probably make a difference if you are using a burner vs electric stove top elements. A burner might give a wide range of temps throughout the pot. I use the stove top elements and had absolutely no issues other than the smoke from the oil, tar and such on the WW's. The oil and tar crud must have worked pretty good for a flux because the ingots came out really nice and cast great!