Cleaning & Fluxing ???

[cigg52]

Melted my first batch of lead today. I have a few questions. Used a turkey propane cooker and a RCBS 10 lb. cast pot. It didn't take very long to heat up to melt the lead.

1). How do know when the lead is clean, it seems like I flux , skim fulx again, skim again and there is still skim layer on top.

2). When I poured the moulten lead into the ingots and after they cool down ,
parts of the ingots are a blue and purple color.

3). Is there trick to skimming, it seem when the top is clean there is still a thin layer of something and I skim again and it comes back right away.

Thanks cigg52

[44man]

Skim once, make boolits until the dross gets in the way and flux, skim again. The lead is oxidizing while you watch. If you want to stop it, you have to turn off the heat and let it get cold. Just a fact of life!
If you are getting frosted boolits or it takes a long time for the sprue to harden, reduce the heat and that will also slow the oxidation.
If you are just making ingots, flux, skim and pour your ingots.

[cigg52]

Thanks for the reply 44man

What about the coloring I am getting in the ingots ? and if I re-melt the ingots will the blue & purple color in the lead, and if so does the coloring have any effect on the lead ?

[Buckshot]

..............The colors are from the heat. Sometimes if the turkey fryer is turned up like a jet engine on afterburner you can get some truly dazzeling irridescent colors on top of the melt :-).

As was mentioned the skin over the top is oxides. The hotter the melt, the faster the reaction takes place. When you run the dipper through it to fill an ingot you expose fresh material which also immediately oxidizes. When you're batching scrap you do want to kind of run the heat a bit higher then when casting. This because you're usually dropping in bigger pieces or at least a fairly substantial amount of new cooler lead.

You don't want to have to stand there 30 minutes for it to melt. If you have a thermometer run your scrap at about 900 degrees. You can also place a layer cheap clay cat litter over the top to help exclude oxygen from the surface. Cleaning off clips then requires a magnet so you're not dipping out bunches of the cat litter too. You can get those inexpensive welder's squares on sale for a buck and a half. Use a piece of wire coathanger to move it around. The magnet is usually a plastic matrix and it'll melt of you're not watchfull.

....................Buckshot

[cigg52]

Buckshot-

Could you use oil-dry instead of cat litter ?

What I am smelting is pure lead sheets with a paper backing, should I still cast at 900 degrees ?

So from what I read, there will always be a skim coat on top even when the lead is clean ?
Thanks for all the help. cigg52

[DaveInFloweryBranchGA]

cigg52,

Oil dry and cat litter are the same thing. Both are dried clay crumbles. Since you're not working with wheel weights, you're temperature is fine, but if you smelt wheel weights in the future, you'll want to reduce the temperature to around 650 degrees F to avoid melting the zinc wheelweights and ruining your alloy.

Regards,

Dave

[cigg52]

Dave -what about the skim coat, will there always be be a thin coat on top of the melt even after you flux and the melt is clean ?

[carpetman]

Cigg52---No you cant use oil dry. Before I knew it was the same stuff as kitty litter and cheaper,I had to suffer and stand in line to be seen with a bag of kitty litter. I want others to have to go through initiation also. Besides if we create a shortage of kitty litter--some cat might get it for ruining a carpet. With the oil dry you don't get a target like you do when you buy a bag of kitty litter.

[454PB]

Yes, it's normal for a coat of oxidized metal to reform almost immediately after fluxing, that's why the guys have suggested the cat litter/floor dry on the surface. It forms a barrier to the oxygen and retards the oxidation. It's really a waste of time to use it while smelting for ingots, but if you are casting it helps slow the dross rebuilding.

Also, since you are melting pure (or nearly pure) lead, that is what causes the colors on the surface.