Smelting lead from boolit trap

[relic]

I started out with 18 lbs of fragments from my trap. After melting I end up with 12 lbs of nice looking ingots. I now have 7 lbs of a strange dross. Nothing can get into my boolit trap except the lead I shoot into it. The 7 lbs of dross is real grainy and under a magnifying glass it looks metallic although it is dark grey to black. I used lots of bees wax and saw dust as fluxing, so anyone have any ideas or have you found the same results from lead reclaimed from a boolit trap? Its lead in and should be lead out in equal amounts, right? I also use card board in the front of trap to pin my targets onto. Think the card board some how is contaminating the melt? There is lots of shredded cardboard in the mix but I sure doubt it would cause any problems.

[Sig556r]

Not from a bullet trap per se but from sifting dirt/sand below a steel backstop...yielded pretty much same as yours (around 65%) with 35% scrap of nasty dross including chunks of rock & dirt...

[30calflash]

Copper plating from HV rounds, lube also. Some other stuff that accumulates on the trap impact area, paint or rust come to mind.

[georgerkahn]

relic -- you got the "wheels" betwixt my ears (a lot of hollow space) spinning. You indicated nothing gets into your trap but "the lead I (you) shoot into it" raises my first query, to wit: Have you shot factory ammo/bullets, or is it exclusively your alloy? I recently read that, bion, battery lead, cadmium, calcium, bismuth, arsenic, and tin -- plus a myriad of unknowns -- are used -- swaging, more than casting, the bullets in commercial factory ammunition. IF you have shot factory ammo in your trap, this might be an answer. HOWEVER --18 pounds melted yielding 19 pounds (12 + 7) indicates you picked up a pound somewhere. (I do that every-time I'm in a donut shop) But, even if one discounts that extra pound, 12/18 = 2/3rds. Even reckoning a lot of antimony, mystery metals, and even sand -- I'm mystified re your results. Re cardboard, the fire point is 258°C, the ignition temperature 427°C. 258°C is 496.9°F -- Fahrenheit being mostly used south of the (Canada) border. Assuming you're smelting at 700 degrees Fahrenheit, plus or minus fifty degrees, all your cardboard should be/have turned to ash -- lo volume, and relatively weightless.
Yes -- the wheels spin -- and, you have me mystified. Do you KNOW the exact temperature you employed to make the "nice looking ingots"? Again, if you employed commercial bullets in your mix, you may have some unexpected metals in a eutectic mix. Some, too (e.g., Woods' Metal) -- a blend of bismuth, lead, tin, and cadmium that melts at 70°C. which is used as the triggering element in fire sprinkler systems where heat from nearby flames melts a plug of Wood's metal, releasing water from the sprinklers.)
The only thing I can add vis both your added weight and the sheer amount of dross might be sand/rocks/dirt which you also mined to make the initial mix?
You DO have my curiousity piqued!
geo

[truckjohn]

If you melt at too low of a temperature - you can "float out" a lot of the alloying elements. Be real careful of stirring slushy alloy....

If you know your alloy is good and are unconcerned with contamination - you can crank the temperature way up and re-smelt at dull red.... Then, all the alloying elements will mix back in.... Just don't stir too hard or you will oxidize a lot back out.

[Conditor22]

Did it look like this?


I get this mixing charred pine sawdust and wax

[OS OK]

I shoot into a steel trap...

and collect frags in a steel bucket, I shoot only PC'd cast rounds...

The fragments I pull from the bucket are fairly clean, sometimes oxidized a bit from the rain or sprinklers...



What I put in, I pretty much get back...no gunk or unknowns, dross is sawdust and some oxidized lead that didn't stir back into the pot...but it doesn't amount to anything...

Maybe you can elaborate some on your system to trap the rounds, that might help diagnose this riddle?

[Conditor22]

OSOK has a large trap that the boolits spin in when they drop and they don't all get pulverized. I'd love a trap like that (and a tractor to move it, no wait I do have a tractor) I'd be happy with a place that had a backyard where I could put a trap.

[tazman]

I used to buy lead scrap from an indoor range set up with movable targets(cable system). People shot everything they had into that. Cast, jacketed, plated, and fmj.
When I smelted it out, I got much the same thing you did in similar proportions. I usually averaged about 7-8 lbs of clean ingots from a ten pound load.
I stopped worrying about what the dross was and just disposed of it.
It had jackets and what appeared to be dirt in it.
The alloy I ended up with would water drop to around 14BHN so I didn't need whatever it was that I threw away.

[OS OK]

It's starting to sound like 'frangible rounds' got mixed in with that load of Pb? Aren't they compressed Cu powder? That'd surely end up in the dross...

[relic]

Ah ****, I just had a really long reply and I did something and now I have to start all over. The 1 pound was an error. Yes, nothing goes in that trap except my own alloy. I buy lyman #2 from MO metals and then I add to it with some of my mystery lead that I collect. #2 is a little hard for me so I lean it out so I get about 12-14 bhn. When I melted this bunch the temp was up to 700-850 according to my Fluke meter with the thermo couple. It got a little warm. I used maple, fir, cedar saw dust and bees wax and some candle wax. As for commerical bullets, very very few. Have not bought a commercial bullet in years. Now when I add tin I use some stuff that is 4.65%copper,.656 lead, 7.25%antimony,0.1%bismuth and 87.24% Tin. Its some dross I picked up at scrap yard a few years ago and had Roto metal anylyze for me. I use it like tin. I went back out to the shop and heated 2 tablespoons full to 1200 degrees and all I got was a pea size piece of lead. So Im going to start all over again and that gives me more reason to do more shooting. Ive been remelting lead out of this trap for 3 years and have not noticed anything quite like this. Again, this wasnt mined, Its out of a 5 inch pipe that collects all the fragments. Thanks for the reply, Im not done with this yet. I may send a sample to Roto for them to anylize.

[relic]

My trap looks just like one pictured. The boolits do seem to strike dead on the center of the collector pipe, thats probably why they turn to dust, maybe I need to off set my aiming point.

[relic]

conditor, yeah, it looks similar . I dont know how to post pic and will probably never learn, too old.

[relic]

tazman, yeah, Im just trying to figure out why if I put say 19 pounds of lead boolits in that trap, why dont I get at least close to that amount back? And why or where did this strange dross come from? The boolits shot good, sized easy were mostly 12-14 bhn and Im happy, but curious why I have this extra stuff that wont remelt at 1200 degrees.

[OS OK]

My trap looks just like one pictured. The boolits do seem to strike dead on the center of the collector pipe, thats probably why they turn to dust, maybe I need to off set my aiming point.

I found that if I insetted one side of the trap it'd prevent the bullets from reaching the collector straight on...



A little perspective of the angles and size...



Also, the angle that the rounds strike the steel makes a huge difference in the amount of fragments that go into the collector pipe. Notice this testing I did before I decided on the specific angle of the sides and top-N-bottom plates...

Building a lead Catcher Backstop 'testing steel plate' Part 1 https://www.youtube.com/watch?v=6bf36dfaF2k

The whole story of building the backstop is here...New Pistol Target Backstop _ It works . . . part 2 https://thereloadersnetwork.com/2018...-works-part-2/

PS to Conditor22...Jim you know I ain't got no tractor...just hardheaded determination of a Texican and my 71 year old brother from Massachusetts, together...ain't no tellin what we could move....(heheheee, so long as we have a good come-A-long !)

[Petander]

tazman, yeah, Im just trying to figure out why if I put say 19 pounds of lead boolits in that trap, why dont I get at least close to that amount back? And why or where did this strange dross come from? The boolits shot good, sized easy were mostly 12-14 bhn and Im happy, but curious why I have this extra stuff that wont remelt at 1200 degrees.

I seem to have that same exact question.

Testing my new trap,I fired ~ 15 lbs of 38,357 and slugs last week. Or 15 lbs is what I got from the trap, quite a lot of dust and small particles there. But only my own alloy. Hard bullets shatter.

Melted it on an electric stove ( that works fine for mixing alloys before going to main casting pot) and there was like five pounds of heavy,grey dross on top. Rust from the trap? No way that much.

I'll try re-melting it with more heat / propane next time,reading this thread game me that idea to try. Lots of heavy,blackish grey powder...? I gave it three hours covered,it should all melt...?

There's all kinds of old scrap visible in the pic, the fine grey dust on top is what I mean. Fluxed with sawdust glowing,didn't mix it back.

[blikseme300]

A few years ago I was all about setting up a trap to recover my alloy. I spent a lot of money and built a pretty good trap that still works. The kicker is that I calculated that I could have bought about 10 years supply of alloy for what I put into the trap. Lesson learned is that unless you shoot enough to justify the investment, don't do it.

Who am I kidding? I am still waiting for all the saving money that casting and reloading will give me!

[OS OK]

That's a strange lookin bunch of lead...this is what mine looks like, a little oxidized from all the small frags but it mostly stirs back into the blend.

Petetander...got any pics of your build we can see?

[Cookr21]

That's a strange lookin bunch of lead...this is what mine looks like, a little oxidized from all the small frags but it mostly stirs back into the blend.

Petetander...got any pics of your build we can see?

Is that a production propane burner you use OS OK? Looks to be a pretty heavy duty setup. Have not seen legs or burner grate that thick.

[OS OK]

Is that a production propane burner you use OS OK? Looks to be a pretty heavy duty setup. Have not seen legs or burner grate that thick.

I kinda imagine it's a ChineeeeeCheeeePo Piece-O-Junk...built to look tough but the metal is thin-walled...I don't trust it for anything heavier than this pot of 50 pounds maximum.
The burner is good, had to repalce the regulator once in 8 years or so...If I were to ever use a propane cylinder bottom for a big pot, I'd use the burner but build a whole new stand from angle iron and tube.
The burner grate is the only solid round stock on it.