Gun Metal Gray Dross in Chilled Hard Shot?

[John Boy]

What is the fine gun metal gray dust dross in chilled hard shot?
* Melted 2 bags - fluxed 2X with Borax
* Put 20# in the pot - fluxed 2X with Borax
* Started casting at 730 degrees and the gray dust dross continued to float on top of the lead
* The more I cast - the more the stuff continued to float on top of the lead
In total, fluxed the pot 5X and the stuff kept appearing.

Perplexed and have no never experienced this because this was a 1st melting chilled shot. Idea what it is and why it continues to appear as dross?

[beagle]

Probably graphite dust. The shot is rolled/coated in grahite before being bagged. I'm assuming, this is dust. I've melted down #2 shot long ago and there was alot of it that I had to flux out and discard.

Any mush looking gray stuff is antimony. Since you're fluxing good, this stuff should alloy in.

After shooting, you may find that you need to remove some of this "mush" as shot's pretty hard and the antimony makes the bullets brittle.

If you skim, it off, save it for hardening pure lead later on./beagle

[runfiverun]

the dust is graphite.
wait till you see the color of your boolits.
small sized magnum shot is a good hardener for some alloys, but the graphite is a pita to deal with.
lumpy frothy lookin kinda stuff is antimony, you need to up the heat at that point and then flux it back in.

[John Boy]

Thanks Beagle and runfiverun - the light bulb went on with the word graphite. The stuff never crossed my mind
These were 2 bags of old Remington #2. There was no mush at all floating on top. Just complete hot melt with the gray dust on top.
I was really surprised - the shot was labeled CH for chilled hard. Expecting somewhere around Bhn 15. When I took a hardness reading: Yesterday - Bhn 8.2, Today Bhn9.6. Should harden a tad more in the next week, presume around 1:20. Nice to have additional alloy to add to inventory for BPCR reloads
Thanks again for the replies