Is my alloy poisoned?

[bcr]

I've always been careful to keep zinc out of my alloy, but I've got a pot here that doesn't look right. These are wheel wheights I smelted into big boule a few years ago and just now I'm melting them down into ingots. This pot looks like it has some kind of skim on top. If I scoop it away it is shiny and mirrored underneath but quickly forms the skim again. I don't think it looks lumpy but I've never had a problem like this before. Will this be OK, and if not, how clean do I have to get the pot before I can use it again?

The first photo is the alloy. The lumpy stuff behind the spoon is not what I'm talking about, I think I can scoop that out. The second picture shows what it looks like when I pull the skim away with the spoon.

[Mitch]

I take it this is after you flux with something.the **** on top just keeps comeing back after you flux and never goes away?.i did this a few yeaers ago never did figure out what was in that batch.never ending dross.i did the acid test on mine and it didnt react.this stuff is now going around a a dirt race track lol.you can allways find a use for it is it will not cast good bullets. I am sure someone will have more of an idea of what you have going on ther . sorry cant help much more than that.

[Winger Ed.]

I had something similar happen years ago.
A buddy had access to a laboratory that could find out what it was.

In my case it was loaded with Cadmium.
I was told it was a big time carcinogen and I gave it to them to send to a HAZMAT site.

[John Boy]

Read the post by sagacious in this post ... http://www.tackleunderground.com/com...y-composition/

[RED BEAR]

I had the same thing i got rid of a lot of it by starting cold adding couple hands of sawdust then heating slowly and stirring as soon as possible. But i am cheap if it melts it gets used. I use the zinc and skim to cast for my shotgun. I also had some that would not melt just got like oatmeal no matter how hot i got it wouldn't melt. My thermometer said it was well past 1000 degrees but i am not sure how accurate it is.

[Mr_Sheesh]

You could send a roughly pea-sized blob of that alloy to BNE with a pound of lead to pay for the XRF analysis and he'll tell you what is in it.

[Stephen Cohen]

I was given some Clip on wheel weight lead that had similar problem. I put a tablespoon of sulphur in the mix and a porridge like scum come to the top and I scooped this off and chucked it. Be warned do not breath in the fumes from this and the sulphur will catch fire and the flame in near invisible so wear gloves and mask and glasses. I found the lead very good after this treatment as my lead was contaminated with Zinc. If it was me now knowing what I do now, I would do as Winger Ed suggested as a pot of lead is not worth your life. Regards Stephen

[odfairfaxsub]

So now we have to worry about cadmium??? Holy dog ****. I had that skin on some lead too awhile back and wondered why it still casted good. Darn it all.

[Winger Ed.]

So now we have to worry about cadmium??? Holy dog ****. I had that skin on some lead too awhile back and wondered why it still casted good. Darn it all.

I only encountered it once with some stuff I got at a scrap yard.

When melted in the pot it slowly comes out and floats as a brownish, fluffy, high volume crud.
Scrape it off, wait a hour, come back and there's more on top.

All in all, its easy to spot, and dump out that pot full.

[odfairfaxsub]

Mine looked like bcr pict

[Tenbender]

Burn a hand full of saw dust or chips on it. The tin will mix back in. You might need to do that more than once while casting ingots. Just scoop the burnt dust off and have at it. Some people use wax but I have a ton of saw dust.

[The Dar]

Sorry, I don't have a clue what your layer of scum is. My question is, is that an aluminum pan you're melting lead in? It looks like one. Be careful if it is. The temperature of melted lead can burn through the pan.

[RogerDat]

Do you have enough heat? Is it possible the top is getting cool enough to skim up? Even a small amount of garden sulfur flux will make a difference. As will sawdust flux that you light on fire once it is smoking well.

You don't say how or if you checked for zinc WW's back when you originally did that batch of WW's.