Plastic weights, pickle stink, and strange oxidation

[jonk]

Well that was interesting.

I smelted some weights together and ran into the usual steel and zinc weights- but something new: a plastic weight. Made good flux though, lol.

When I got all the clips out, the melt oxidized like it might normally with pure lead- very quickly turned gold then blue. Even after fluxing 3 times, once with marvelux, once with saw dust, and once with wax. Yet it is most certainly very hard. And the temp wasn't higher than normal. Very strange.

Stranger still, it had the stink of pickles. Not sure if this smell was some of the residual plastic stuck to the walls of the pot or what.

Pouring it, it was lumpy and gloppy- almost as if it had zinc melted in; but I used a thermometer and never took the temperature high enough to melt zinc. Of course, that was an infrared, tested at the top once things started to melt. if I had the bad luck of getting a zinc one at the bottom before I could check the temp of the melt, and it was right up against the heat, oh well.

Not sure what was in this batch, but very puzzling indeed.

We'll see how it casts later. Fortunately, it was a small batch.

[Harter66]

I had a batch that did that early on. In reflection but it was sourced from metal that was VERY high antimony (10-12% IIRC) ,the chunky/oatmeal part . 1/1/1 w/it /1-20/pure got it down to more or less the hard side of ww. Its unliky w/your triple flux that you had a ''floating'' layer of pure or tin unless somebody slipped in a bunch of 1/2# solder bars. They might pass off as 8oz truck weights.

[jonk]

Well whatever it is/was, I tried casting with some of it. So thick it wouldn't flow through my bottom pour, had to dump it in the little Lee 5 pound pot and run it on high. All sorts of pretty colors. Very hard stuff. Very hard to cut the sprue. Cut it with 50% pure lead and that helped a lot. Good bullet fill out, the oatmeal stuff went away more or less, still rates an 8.5 BHN after being cut; so I think I got some pure tin in there perhaps, or some other hard alloy. Or some zinc too, but not enough to ruin fill out once I cut it with pure.

Only about 8 pounds, just had a small batch of weights sitting around that I figured I'd melt down; so it won't take forever to get rid off.

[runfiverun]

zinc is soluble in lead alloys to about 2% before it becomes problem enough to notice or even show the oatmeal effect.