Smelting/fluxing?

[epj]

I am casting pistol boolits out of primarily WW's with a bit of range scrap thrown in. When I smelt the WW's, I flux pretty regularily and try to get the mixture really clean. My question is how do I tell if I am removing just the junk from the alloy and not removing tin/antimony at the same time? I get the usual powdery stuff along with the clips, dirt, road grime and other stuff you would expect, but also get some amount of what appears to be tin floating on top. My boolits don't seem to have the nice shinney look that I see in other casters products, or that I used to have in the old days of casting. Back then, I used a lot of linotype and probably could have taken out a lot of tin without it mattering. My boolits seem to shoot fine, just aren't as pretty as the ones some of the rest of you make. I am using Lee molds, which I note are not as nicely finished as the Lyman/RCBS I used years back, but the price is right and they aren't nearly as heavy as the steel molds. Years ago I tried to use a 4 cavity Lyman .45 mold and it wore me out is short order. I can imagine how it would be 30 yearsw later.

I usually flux with a bit of candle wax, pariffin, or sometimes just the wood dowel I use to stir with. Sorry, I don't own a thermometer that reads that high, but judging from the appearance of the ingots, they probably aren't getting hot. I sometimes get a few frosted ingots, but most aren't. I try to keep it as cold as possible to fettet out the zinc. Do I need to be doing something differently? Yeah, I know. I need a thermometer, but it would have to be a really cheap one. Funds are tight at the moment.
Thanks in advance for and thoughts or ideas.

[docone31]

Here is what I do,
I use a bottom pour pot for casting, I ingot out of a cast iron pot. I use a Lyman ladle for ingoting.
When I congregate the metals to ingot, I crank up the heat. I pick out the clips, jackets, and any other large crud. I use Kitty Litter for flux. I make my ingots useing the ladle, pushing aside the small floating stuff. Eventually, most of the floating stuff breaks down and either turns into a grey/brown powder, or it melts into the melt.
After I ingot, I use again Kitty Litter for my casting pot. It floats. I can even toss my rejectd directly on the melt in the pot and I water drop! The rejects reside on top of the Kitty Litter untill they drip into the melt. When I stir the pot, oxides float up to the Kitty Litter.
In time, I do screen the top of the pot. I use a perforated spoon and let the molten metal drip through. I can get the top of the melt pretty oxide free, at least for a short time.
I like leaving the dross on the melt, With a bottom pour pot, it acts like an insulator, stuff that is not castable clings to it. Eventually, the Litter breaks down from clumps to powder. It starts looking like a large amount, then gradually gets smaller as it powders.
If you have a bottom pour pot, you might be cleaning too much.

[454PB]

Don't worry about it, tin doesn't "separate" from lead alloy, it oxidizes away. Nothing you do will prevent that, but keeping the temperature controlled, leaving the dross on top or adding kitty litter will slow it down.

I don't flux until the metal is at full casting temperature, which for me is about 725 to 750 degrees. If you flux when the melt is too cool, you will get the accumulation of alloy dispersed within the dross. If that happens, just let it heat some more and flux again. This is especially important when using monotype. You'll get a thick layer of "froth" on the top of the melt. The natural tendency is to remove that froth, but if you let it heat some more, it will eventually blend in.

[epj]

Don't worry about it, tin doesn't "separate" from lead alloy, it oxidizes away. Nothing you do will prevent that, but keeping the temperature controlled, leaving the dross on top or adding kitty litter will slow it down.

I don't flux until the metal is at full casting temperature, which for me is about 725 to 750 degrees. If you flux when the melt is too cool, you will get the accumulation of alloy dispersed within the dross. If that happens, just let it heat some more and flux again. This is especially important when using monotype. You'll get a thick layer of "froth" on the top of the melt. The natural tendency is to remove that froth, but if you let it heat some more, it will eventually blend in.

What is the shiney stuff that floats on the top? I assumed this was tin.

[docone31]

Not always the case. An alloy is not usually broken down by heat unless one component or another goes gaseous.
Those scales you see in a clean melt is a large scale crystal of the melt itself.
Some alloying components that are not in alloy will escape.
Look at it this way, if you melt brass and it cools, you still have brass. If you melt it and it boils, the zinc vaporizes reduceing the alloy.
One of the reasons zinc will float to be seperated by dropping the heat, the zinc is not in total alloy state. It is in colloidal state. The components that are in alloy will remain unless there is metal in a gaseous state.
When I melt brass, and my furnace is too hot, I get zinc oxide crystals on the rim of the crucible. They form where there is oxygen. I still have brass although I have modified the alloy.
Those sheets you see on top of a clean melt are crystals. Albeit large crystal sheets, almost like tectonic plates. When oxides form, they become crusty. Still, it is oxide of the prime alloy.
That shiney stuff is unoxidezed alloy.
Anything that is unstable in the alloy though, will oxide off the melt.
Another example.
When I melt karat gold. I can only melt it once. Gold itself is stable, the alloy components are not stable in the alloy. A second melt makes the gold brittle, and orange when in contact with salts especially from the skin. One of my largest mistakes starting out was to take scrap, melt it into balls, roll it in my rolling mill to make sizing stock. I then added it to the customers ring, or whatever. I used to let them watch figuiring they were interested as I had been.
Wrong.
Those pieces turned orange in four weeks. The repair piece showed immediately. It was embarassing. Try telling a customer that orange piece is 14kt gold.
When I cast gold, I add metal to bring up the alloy. It drops the karat so I have to compensate for that.
I have not found lead alloys to do that, at least not in what we do. The only way I know to seperate the alloy is useing Muriatic acid and chlorine. That dissolves the metal. It can be then dropped out useing sodium meta-bisulphate. The tin drops out by adding hydrogen peroxide, then adding sodium meta-bisulphate. I do not know about antimony. One gallon of Muriatic acid can process five ounces of metal.
Don't worry about the scales.
If there is any seperation, it is from excess components in the alloy. An alloy will remain an alloy unless it is physically seperated.
You can however seperate lead useing sulphuric acid and electricity. The lead will seperate at the anode.
As sodium chloride and electricity will rapidly dissolve gold alloys, it will also dissolve lead alloys. Sodium chloride will dissolve lead alloys slowly in comparison to electrolysis.
I do not believe an alloy can be seperated under heat in a centrifuge, but, I might be wrong there.
I just enjoy the beauty of the melt and cast away.