What did I do wrong?

[AggieEE]

Decided I wanted to experiment with some copper in 50/50 COWW/SOWW alloy. So after finding some copper sulfate I took 10#s, really closer to 11, of stickon WW and melted it with a 1.6 oz zinc ww. If my math is right that's a 1% concentration. If I remember my chemistry, that's about 6oz of copper sulfate pentahydrate. So I added a little copper sulfate let it turn white then stirred it in add a little more etc. I started getting a sludge on top that was more like a lead alloy that is almost melted but not fully. Thinking that zinc was causing the problem I added a little more copper sulfate, a total of about 9 ozs, I think it got worse instead of better. So thinking it was a dilution problem I added the coww. Didn't help, so I skimmed off the mush, about 5 or 6 pounds worth, and casted up the rest in Lyman ingot mold. I ended up with 3 ingots instead of the 4 + I should have gotten. I need to check to see if my local scrapyard has an x-ray gun and how bad they'll hurt me to shoot the ingot and skim. I either have a really high copper alloy there or a lot of zinc. So the question to the experts is what did I do wrong and how can I keep from doing it again? Thanks guys

[ikarus1]

you added zinc? for what purpose?

[AggieEE]

The copper sulfate leaves the copper in the lead and forms zinc sulfate. Zinc is more electro-negitive than copper. Just like a copper wire will form a silver dendrite when dropped in a silver nitrate solution. According to the experts here its easier to get copper in solution this way than trying to dissolve copper wire in lead. There's a couple of threads here on copper in lead alloys.

[popper]

What you skimmed is probably just alloy that didn't stay melted - not eutectic so some has different melt temp than the rest of the alloy. You did get lots of light weight brown powder on top? The powder you throw away, sludge you keep and mix back in. Seems the higher Sb content the more sludge you get. You should get all the powder out - keep stirring till no more forms - really scraping the pot good.

[AggieEE]

popper, didn't seem to get a lot of brown zinc sulfate. I was also thinking not getting hot enough but I was getting a dark purple in some areas of the melt. Not going according to what I was reading. It is confusing the you know what out of me.

[popper]

With that much zinc you should have more than a pint of brown powder. Did the zinc WW melt? Was it really zinc or that funny stuff they use now? I usually run the pot close to 800F when I do this.

[AggieEE]

Well, the wheel weight had a Zn on it and it was very dent resistant. It did melt as I didn't find any little pieces except for the steel clip. Maybe I couldn't get it hot enough as my heat source is a single burner camp type propane stove. The burner is about 4" in dia. I was using a old 10" dutch oven cast iron pan so I think I had enough. I got nowhere near a pint of brown powder, almost none. If I need more heat I need to find something else for a burner. I know it had enough heat to boil 5-8 gallons of water in one of the big GI cook pots. My grandmother used it to blanch corn before making creamed corn out of it to freeze.

[Oklahoma Rebel]

well , I don't have a calculator handy, but it kinda sounds like A- a bit too much copper sul. and B- I don't use zinc at all. I only use copper in my lyman #2 alloy, and I mix it to about .5%, the copper replaces a bit of the tin, but man, after aging this stuff is hard! yet not fragile. I do heat treat the boolits (for high velocity loads in rifles) but I don't have a tester, and honestly, the un- heat treated ingots sound plenty hard, that I might not have to H-T the rifle boolits. I would increase your head and add wood shavings, and it you still have that sludge, if it were me, I'd skim it for testing later. good luck, sorry you r having trouble. this is why I avoid zinc!-Travis

[popper]

OK, I think I did the same thing several years ago, had another report of similar results. If/when you dump the Zep on the melt it will turn white and globby. Gently push it slightly under - watch for water bubbles - control til you just get a little steam and no tinsel fairy. Eventually it will dissolve and create the powder. The glob does look kind of silvery. Put your skim back in, try again and really 'work' the stuff with a spoon, crushing the glob on the pan side. I usually cook for 1/2 hr to get it all mixed in. Flux well to get all the powder out. It also converts tin but Zn is MUCH cheaper. I.E. add tin AFTER conversion if you need it - I don't use it and casts fine.

[Oklahoma Rebel]

I factor the tin needs in with the alloy so I don't have to worry about adding more after addin the C.S, one questions though, if I ad .5% copper, do I lose exactly .5% sn? or more or less?thanks. original poster, reheat it., do what popper says, really work it in, I use a paint stirrer to smash the crystals against the wall, the crystals should be grey, if the copper is all out of it and into the alloy, and do the same with whatever else is floating on top, unless you put too much zinc in, how much did you put in,weight, or how many ww's and were they big or small, that could still be an issue, luckily it can be skimmed off, next time I would do like I do and add a little exta tin to whatever alloy you are mixing, I got it right the first timm, never had a problem (I AM NOT BRAGGING, JUST LUCKY, MY SHADOWS NAME IS MURPHY) LOL -Travis

[Oklahoma Rebel]

I just re read your post very carefully, when you added more cs you have way more cs than zinc in there and ww's have almost no tin, I think if you add an ounce of tin it will clear that problem up, and the boolits will cast a lot better too

[AggieEE]

UPDATE: This weekend I dumped the sludge back into my smeltting pot and re-melted it. This time I kept smushing the paste up against the side of the pot and slowly I started getting a clean melt. Popper was right, I got a ton of brown powder out of the melt. Since I knew I had a highly copper rich mixture there I put my other 3 ingots back in and added another 5lbs of lead and 3 of WW. I also had a blob of something, maybe Lyman #2, added it and about 3 lbs of magnum shot for the arsenic. I ended up with about 40 lbs of mix so I've got something to play with. If it works good I'm not going to try to duplicate it, I'll start over and do it right next time. Again thanks for all the help.

[Grmps]

I like using a potato mashers to flux with in my casting pot and something like this "Hiware Solid Stainless Steel Spider Strainer Ladle, 5.4 Inch" attached to a metal tube https://www.amazon.com/Hiware-Solid-...words=strainer
To flux and mix in my smelting pot. For me, they do a quicker/more thorough job of fluxing or incorporating additives to my lead.

[popper]

Glad it worked OK for you. Get out and make holes in something, you'll like it.

[USSR]

Now I've heard everything - A guy who INTENTIONALLY added zinc to lead.

Don

[popper]

USSR - I tinker a bit. ~0.2%Zn/0.3%Cu/pure works well in 40SW ~ 850 fps ~30Kpsi (190gr 401-175 beagled). Upped the Zn to 0.3% and got near as hard as isocore. Trying for an alloy that will take 1800 fps loads in MG 30/30 and expand (soft nose) without making 2 part boolits. Adds ~ $0.05 to a pot of alloy.

[MyFlatline]

I haven't added zinc yet but do mash the Copper Sulfate to powder. beware or the tinsel fairly tho..make sure there is no blue.

[NoAngel]

Wouldn't it be easier to just get some Cu babbit from rotometals? It mixes perfectly and so much easier to work with.

[AggieEE]

No Angel, what and loose the ability to say " I did it myself??"

[NoAngel]

I certainly do understand that. At the same time, sometimes doing things yourself is a dime holding up a dollar. If you're like me, it's difficult to distinguish where that line is.