Salvaging bullet alloy from slag


Active Member
In my casting- and smelting area, I have a growing heap av slag. This obviously contains quite a lot of metal, as it is heavy. And in theory, it should be richer in the alloying compounds than the alloy from which it is skimmed (because of the oxide layer/incomplete flux reduction). Therefore, I have wondered wether it is possible to salvage the metal contained in the slag.

Today, at the end of a little smelting seession, I tried to melt the some of the slag to see if I could segregate the alloy contained within. Melted it on a burner, and used a gas torch to heat the top layer. It segregated nicely. The salvaged alloy has a «pencil hardness number» of 20-22, while the original alloys from which the slag was skimmed was BHN13, and 18.
Maybe I am to impatient when I flux and skim my melt, throwing away antimon/tin before it can be reduced back into the melt....
Anyway, salvaging the alloy contained within my slag heap seems to be both simple and quick enough to be meaningful. F95F97DF-1337-46F3-BF7C-D264A661E8AC.jpegC88F25DC-C16D-427F-BF91-78DBD60E9EDF.jpeg


West Central AR
I get up to a gallon or so and drop it in the melt pot with 50-60# of WW , the especially gross ones , paint , grease , oil etc .

S Mac

I too save it and just add it to a wheelweight rendering session. I would just add your special ingots one at a time to the pot of your other alloy to sweeten the mix.


Well-Known Member
I throw mine in a metal bucket that has a couple of holes in the bottom.
when I melt ww's the first thing I do is set the bucket in the bigger pot and light it up, then start the smaller pot full of ww's.
all the ingots I get from the bucket get mixed back in with the pots of melted ww's from there on out.


Well-Known Member
I render all the slag separately because it already contains junk I want rid of. Lots of sawdust and diesel fuel gets it pretty well reduces and anything skimmed from that mess gets entombed in cement inside a can and buried.


Well-Known Member
I do about 15 or 20 lb. a time in an iron
pot on a hotlplate while I am casting. It
is worth the time.



Love this discussion. I still have all the slag I've ever had but have never done anything with it. Always new there was gold in them hills.

358156 hp

Well-Known Member
I keep mine in the bottom part of a really, really old Winchester Powder 3 lb can (296 IIRC). It takes a couple of years to fill it, and when it is full I melt it in the can, set on my dutch oven on the propane fish cooker. I dump it in the dutch oven when it's liquid enough. It sort of self fluxes a bit because I toss my used stick matches in the same can. After some serious fluxing I add more scrap lead & flux it some more. It always comes out really nice, and I'm betting that that first pot is probably much higher in tin than the pot loads that follow.


Active Member
I find that if I don't flux with both pine sawdust AND wax I end up with more lead in my slag
I use a large wire wisk to help with fluxing.
When I flux my casting pot I start with a potato masher, then a small wire wisk

Alan in Vermont

New Member
I save my dross, along with anything I'm not sure of, last few ingots of an alloy I don't plan to duplicate, etc. in one bucket. When the bucket gets full I melt it all together, fluxing heavily, and pour it into ingots. The ingots get stamped with a code to identify them for later use. The last batch I did was "MM18", Mystery Metal 2018. A sample gets sent for testing and the test results entered in the Alloy Calculator making it available for mixing into more alloy.