Lead question

[patio]

I am using sheet lead to cast bullets for my Civil War guns. When I get the molten lead temperature to 900+ degrees, I get all kinds of crud at the top that I need to remove. This crud in the melt does affect bullet quality. Am I removing impurities? Is my melt too hot? Need help to figure out what I am doing wrong. Thank you very much!

[Winger Ed.]

Flux & stir it like it owes you money.

Sheet Lead is usually pretty dirty, and ya want to float up as much of that dirt & trash out of the pot as you can.

[patio]

Thank you Winger Ed. There is A LOT of crap that needs scooped out. Some of the bullets come out real pretty. Thy have pink, blue and gold flecks in them.

[jednorris]

I have been casting for years but still do not know about impurities. I melt my lead and take out the big junk, then add Beeswax and torch the smoke. That leaves me a black sticky film, what is it? After removing that, I add some "Marvelux" which boils to the top and forms a crusty blob. What is the "Marvelux" removing? I then feel my mix is ready to use, is it?

[BLAHUT]

I use a bottom pour, I scrape the crud off and don't worry about it. Casts good soft lead bullets for me....

[Dave W.]

900 degrees seems pretty hot to me, I run about 725 degrees. I flux with sawdust, stir it well and scrap off the impurities, then flux and clean off again.

[Winger Ed.]

Thank you Winger Ed. There is A LOT of crap that needs scooped out.

You're more than welcome.

Years ago I had a customer buddy that had worked at the old Dallas Lead Plant most of his life.
He'd bring me all sorts of 1/4"x4x6" plates that they'd been sent to spectrometer/analyze from samples of 60 ton batches
that were going off somewhere to a manufacturing plant. Some were as hard as Chinese Algebra.
He'd tell me to put a little bit of them into cast boolits to make them real hard.
I suspected they were batch samples to go off to make car batteries.
Once they zapped the sample, they'd just toss the the plates back on the pile of scrap that came in to be recycled.

Once I told him I'd scored 3-4,000 pounds of sheet Lead from a big hospital X-Ray room tear out.
He made a face and said, "Oh that sheet Lead is nasty. When you go to melt it-- You won't believe how dirty that stuff is".

[405grain]

900+ degrees is too hot. The crud that's floating up might be lead oxide from having the melting pot too hot. You only need to go up to around 750 degrees. Once the lead is melted it's hot enough.

[georgerkahn]

I have been casting for years but still do not know about impurities. I melt my lead and take out the big junk, then add Beeswax and torch the smoke. That leaves me a black sticky film, what is it? After removing that, I add some "Marvelux" which boils to the top and forms a crusty blob. What is the "Marvelux" removing? I then feel my mix is ready to use, is it?

jednorris -- I have many times read that Marvelux removes all the good stuff from your melt. Do I believe it? Just a very wee bit. Marvelux continues to be my "go-to" flux. Soooo many times after using sawdust, candle wax, and other "recommended" fluxes I still get not-acceptable to me bullets. I drop in some Marvelux, stir the heck out of it, and voila! the bullets drop as I desire. Frankly, I understand that Marvelux may remove some tin -- but if so, I'd rather have that accompany all the bad stuff -- and then add a few pieces of pure tin purchased from RotoMetals to replace it -- which has become my general practice.
I have no idea what you are starting out with, sir... BUT for me -- as I wrote -- after Marvelux my melt is pretty much ready to use. Drop a few bullets and see what they look like. I stated, and do add a few pieces of tin, but that's 99% 'cause I'm a bit compulsive :).
geo

[JonB_in_Glencoe]

Sheet lead is pure, or near pure. It melts at 621º and you should not need to cast much hotter than 100º higher than that. If you are ladle casting, then fluxing with a bit of beeswax will help a lot, scoop out any of the black powdery dross that forms. No need for high heat, no need for colors, just want it silver.

[jednorris]

Thank you for the response, I am in the Bee business so wax is free. I assume the black film is called Dross, I just skim that off before using the Marvelux. All my bullets are nice and pretty, so I have no complaints on how they turn out. Again thank you for the support.

[GregLaROCHE]

I like to use bee’s wax, but after I have fluxed with sawdust. After the bee’s wax, I add more sawdust, stir and leave what comes to the top there. I think it helps keep the hot lead from oxidizing too fast. This is with a bottom pour pot of course.

[bowfin]

900 degrees seems pretty hot to me, I run about 725 degrees. I flux with sawdust, stir it well and scrap off the impurities, then flux and clean off again.

I agree with Dave and 405; 900 degrees is too hot. If one is melting wheel weight or mixed scrap, that would easily melt any zinc in the mix and that would get messy.

[patio]

Thank you for all of your replies.