What is this hard Black stuff?

[MGK3]

Ok

I melted down 25 lbs of magnum shot into ingots, fluxed with marvelux with a new LEE bottom pour 20 lb pot.

1st question, I ended up with alot of black granular stuff stuck to my stirring spoon and in the bottom of the pot. Hard to remove, What is this stuff and how to remove? The pot bottom and spoon are covered and I seem to be able to scrape it up but not easily. What should I do about it?

2nd question ingots measure 8-10 BHN using a Lee Hardness Tester, what should I add to increase hardness?

Thanks in advance

MGK3

[Larry Gibson]

Ok

I melted down 25 lbs of magnum shot into ingots, fluxed with marvelux with a new LEE bottom pour 20 lb pot.

1st question, I ended up with alot of black granular stuff stuck to my stirring spoon and in the bottom of the pot. Hard to remove, What is this stuff and how to remove? The pot bottom and spoon are covered and I seem to be able to scrape it up but not easily. What should I do about it?

2nd question ingots measure 8-10 BHN using a Lee Hardness Tester, what should I add to increase hardness?

Thanks in advance

MGK3

That "black stuff' is graphite. Shot is coated with it to keep it from sticking together and to go through loaders without bridging. It will most likely cook off the bottom and float to the top when you flux the next batch of alloy. Just scrape it off wihth spoon after fluxing. I melt the magnum shot in a seperate small pot over a propane burner and make ingots before it goes into the regular electric pot.

You can add tin if you want to; about 3 - 5% would make a reasonable alloy. However, it would be a waste. It is the antimony in the lead/antimony magnum shot that makes it hard. If you cast the bullets hot of the lead/antimony alloy and imediately water quench them they will harden up nicely. They will also maintain their maleability when hard instead of shatter or shear for game hunting. With magnum revolver GC'd bullets you can cast them straight with the lead/antimony alloy and let them air cool then push them with very good accuracy to 1400+ fps out of 6"+ .357/41/44s and have an excellent bullet that will expand at reasonable handgun ranges.

Just some suggestions.

Larry Gibson

[Calamity Jake]

It's the marvelux and graphite that was on the shot. Try boiling it out with soapy water, if that doesn't work a wire wheel on a electric drill works, a cone shape for the bottom and round for the sides, then rinse with water.
Marvelux is a good flux but t does gunk up your pot and spoon and it draws moisture from the air. Use some thing else for your casting pot.

[454PB]

I use Marvelux because I do my casting in cold weather, indoors, and don't want smoke and soot collecting. Yes, it causes some black dross- like build up on the inside of the pot, but don't worry about it. Scrape the sides of the pot as you stir and flux, it comes loose and floats on the surface. I leave the dross on the surface (I use a bottom draw pot) until the pot is empty, then clean it off. The dross actually forms an oxygen barrier and helps keep the melt clean.

Calamity Jake is right about It's tendency to absorb moisture, I always preheat my fluxing spoon before plunging it into the melt.