Odd looking "dross"

[LostSoul]

I've just started casting recently, things are going well thanks to what I've learned at this forum! I've made sinkers and jigs with lead once or twice in the past, but obviously boolits have a bit more to consider than something that's just dead weight.

I don't have any specific problem to address, (boolits have come out nicely and quite accurate, despite my shooting skills) but something strikes me as funny while casting. I use small ingots of wheel weight metal in a 10lb Lee pot. After casting for a while, I get a decent amount of what I guess is dross, but it doesn't match the usual description I've seen posted. When the pot starts getting low, there's a good amount of a tan colored powder-like material on top of the melt. I never thought much of it, I'd leave it on to insulate the metal then just skim it off and add more metal. But I got to wondering if this is some kind of oxide or something that I'm removing that I shouldn't be. I flux by stirring with a pine stick and occasionally drop in some crappy commercial cast bullets and use the lube as additional flux.

Again, no casting problems to report, I'm just curious as to what it is. There ends up being a lot of it, about 1/2" layer on top. It looks sort of like clay dirt... tan colored and grainy to powdery in texture...

[JSnover]

I think you have nothing to worry about. You're happy with the boolits that drop from your molds. Your stick is turning to ash, as it should, and leaving a protective coat on top of your melt. It's most likely a product of the pitch or resin in the pine, unless something else has got into your pot. Some people get fine boolits with a layer of kitty litter or sand on top.

[LostSoul]

Thanks for the reply! I figured it couldn't be anything TOO important, considering my boolits look good enough and shoot very nicely. I was just wondering what it is, or what's causing it. Plus another point, is it hazardous or poisonous? I've just been trashing it...

[sagacious]

...
After casting for a while, I get a decent amount of what I guess is dross, but it doesn't match the usual description I've seen posted. When the pot starts getting low, there's a good amount of a tan colored powder-like material on top of the melt. I never thought much of it, I'd leave it on to insulate the metal then just skim it off and add more metal.
...
Yes, that's dross. What you're describing is common with ww alloy. That crud will buld-up as you're fluxing your metal, exactly as you described. After remaining heated for a while, it will look like that.


Again, no casting problems to report, I'm just curious as to what it is. There ends up being a lot of it, about 1/2" layer on top. It looks sort of like clay dirt... tan colored and grainy to powdery in texture...
Just be sure to skim it all off before adding more metal. It contains lead oxides, so dipose of it safely. Sounds like you're doing OK. Keep up the good work. :drinks:

[Calamity Jake]

"Just be sure to skim it all off before adding more metal. It contains lead oxides, so dipose of it safely."

You want to keep that lead oxide, refill the pot first let it come to temp, flux 2 or 3 times then skim.

[jsizemore]

LS, I use a piece of heart pine to flux and scrape the side of my pot. I get a good size buildup of that brown powder on top of melt. I leave it on top to insulate the melt from oxidation just like the kitty litter. It makes no sense to me to scrape one off and add another, especially when the bullets turn out so good.

[sagacious]

You want to keep that lead oxide, refill the pot first let it come to temp, flux 2 or 3 times then skim.
Yes, you're absolutely right. Only skim after fluxing.

But the residual dross after fluxing will always still contain some lead oxides, and should be disposed of with that in mind. :drinks:

[SciFiJim]

But the residual dross after fluxing will always still contain some lead oxides, and should be disposed of with that in mind.

Keep this and collect it until you have a can full (I use a large spaghetti sauce can). When you have a bunch, melt a good ingot in the bottom of your smelting pot, then melt the dross and cover with a layer of sawdust to flux heavily. You can use this method to recover a lot of the lead and tin oxides into elemental metal.

[sagacious]

...
Plus another point, is it hazardous or poisonous? I've just been trashing it...
Yes, it should be considered hazardous. There is no practical way to remove absolutely 100% of the lead compounds at hobbyist temps and with hobbyist equipment.

One recourse for disposal of smelting (foundry) waste is to contact your local fire-dept. Many municipalities have an amnesty-day where you can turn-in any hazardous substances that may contain toxic materials such as lead to your local fire department.

Hope this helps, good luck. :)

[Trapshooter]

I leave some lead with the dross, and take it back to the recycle yard where I buy the lead in the first place. They recycle "dirty lead" in a safe, legal manner, which takes care of both the legal and moral aspects of getting rid of the stuff. They don't give much for it compared to "clean soft lead" or "wheel weights" which are two other classifications of lead scrap.

Trapshooter