Question for the Forum about range/scrap lead

[Carolina Cast Bullets]

Gentlemen,

I have always been of the opinion that dirt/trash and so on would normally float on the melt to be skimmed off and disposed of. Such is not the case, or at least in my experience.

True, a large amount of junk/trash/dirt/etc does float after fluxing and is skimmed off. What is confounding me and my bullet making is that with a bottom pour pot, such as I use, the melt accumulates a large (relatively) amount of crud/dirt on the bottom that quickly clogs the spout. This residue can also solidify to the point where a pick or wire will not clean it. Even once cleaned, it quickly clogs again.

My question is simple, even with fluxing well using a copious amount of sawdust, where does this "dirt" come from and how can one remove it from the melt? Skimming is not a completely viable option since it seems to be in the form of a fine black dust. The source of the range scrap is a local police indoor range and often contains shotgun wads as well as what appears to be slugs deformed against the steel backstop. Could this "dust" be from shotgun pellets? If so, can it be reclaimed as melted lead? (wads and paper/trash and so on are removed before melting)

I might add, the range is "supposed" to be used for pistol practice only but we all know how that goes, specially on unsupervised ranges. I am specially vigilant for loaded rounds that "find their way downrange".

Jerry
Carolina Cast Bullets

[Joe504]

Are you stirring and scraping the bottom of your pot?

[USAFrox]

Yeah, the stirring and scraping, along with the flux, should move all the **** to the top. However, you really shouldn't smelt in a bottom-pour casting pot. Better to smelt in a separate smelting pot, and only cast with clean lead in your casting pot. Saves you a world of trouble.

[Carolina Cast Bullets]

Yes,
Using a cast iron dutch oven for smelting/melting and scraping/cleaning the pot as the melt accumulates. Also using large amounts of sawdust for fluxing. As described, the contamination seems to be in the form of fine black dust. Since there are often shotgun wad and what appears to be slugs, I was thinking the black stuff might be some form of graphite or coating on the shotgun pellets. The bottom pour is for bullet casting only. I learned that the hard way a long time ago.

Jerry
Carolina Cast Bullets

[SniderBoomer]

I ruined my Lee bottom-pour when I was beginning, thought I could refine range scrap with it.

It soon blocked up the hole so bad I couldn't even drill it right again to get a good mold pour.

So keep a separate pot for cleaning lead, save a lot of heartache, as bottom pours are not cheap.

I found sawdust better than everything for fluxing. I get bags of the cheap stuff for critter pets.

Wonder if that stuff they place in water filters would be any good once its dried out again?

[Defcon-One]

You only need about 1/4 to 1/2 cup, max of sawdust in a 90 lb. pot of lead to flux it well. Any more and you are just wasting it. It creates a bunch of black dust, some of which could stay suspended in the lead. Not sure if that is your problem, but it could be.

I would also make sure that your pot temperatures are no higher than 725-775 deg. F when casting, around 650-700 is better for smelting. Any higher and you will get more oxidation which can cause yellow, black and brown crud to stick to the sides and bottom of the pot. It builds up over time. I'd also flux with clean dry Pine Sawdust. (I make my own, so I know exactly what is in it!) Throw it in, get it burning and stir aggressively for a minute or two. That should do it!

[btroj]

That is why I don't empty my smelting pot completely. I carefully add more scrap to the 1/4 inch or so of melt left in the smelt pot. Tinsel fairy is possible so I use a long handled shovel until I am about the melt surface.
Every time I am done smelting I leave some melt in the pot. Before the next smelting session that disk of metal is dumped out and the bottom of the pot is scrubbed clean.

In short, yes, some dirt and stuff stays in the melt. I think the best way to reduce the amount is to smelt once making piles of ingots from each pot full. Next time out add even amounts from each pile to the pot and remelt. Flux again and remove the stuff that comes to the surface.

A double melt like this does two things it removes stuff that made it thru the first smelt. It also makes for ore consistent alloy as we mixed the various batches together in even amount.

[41 mag fan]

Another good way i found to clean a smelt is to use an oak dowel rod to stir with. I use it in conjunction with sawdust.
The black could be from dirt too. I had a lot of sand in my last smelt, which was a gray color.
Graphite could be what you're seeing, but i'm not going to say for sure as I've not had that experience.
The wads and any plastic that gets melted will come out on top as a black blob of gunk.

[merlin101]

If the LEO's are useing shotguns could it be from some form of door breaching round they practice with? I believe they are made of some form of sintered metal, I'd think it would float but I have been wrong before.

[oscarflytyer]

I stir/scrape with a paint stick when smelting and casting. Smelt in a large Cast Iron Pot (soon to be a 1/2 propane can), and dipper cast from a small (20 lb) cast iron pot.