Odd alloy.

[Dumasron]

A few weeks back I asked for suggestions about how to break up a large lump of lead. Now that I have it smelted for the first time There are some unexpected results. It has a frothy-purple or black slag on each melt, and the ingots poured from it have a gold tint on the surface. Further, it is about twice as hard as the alloy I would prefer. It measures about 30 to 45 on the Rockwell Red B scale, and my ideal bullet is about 15 on the same scale.
Clearly there is more to be learned here. Does anyone have insight as to what this alloy is; and how to get it back to a
condition which can be used for soft lead bullets?

Thanks

[500MAG]

Sounds like the pure thing to me.

[500MAG]

Check out this thread:
http://castboolits.gunloads.com/showthread.php?63550-Gold-and-purple-and-blue-Oh-My!&highlight=Purple+gold
The hardness is confusing.

[lwknight]

With a rainbow of colors and very hard alloy sounds to me like a high bismuth content.
It should have melted at a low temperature as well.
Did you check the temperatures?

[KYCaster]

I'm a bit confused by your post.

Do you mean Rockwell B or is it actually Brinell hardness you're referring to? 30 to 45 Rb is equal to 67 to 79 BHN and 0 Rb = 53 BHN. Those values would be REALLY unusual for the Pb-Sb-Sn alloys we normally use.

Heavily oxydized pure lead will have a crumbly gray layer on the melt which, when fluxed will reduce to a fluffy black dross. The purple and gold colors are also consistent with pure or nearly pure Pb. If tested on a Rockwell machine with the Rb penetrater, the results would be wildly inaccurate because the hardness is so far below the Rb scale.

OTOH....The ink on type metals will often result in a frothy purple layer that will reduce to fluffy black dross. The copper in foundry type could possibly be the source of the gold color on your ingots. (I don't know for sure since I never ingotize type metals.) And foundry type hardness could be in the range of 30 to 45 BHN.

Does this help any, or just add to the confusion?

Take one of your ingots and clamp one end in a vise. Beat on the other end with a heavy hammer. Type metal will break pretty easily and pure Pb will bend rather than break.

Good luck.
Jerry