Crud in the Pot

[hylander]

So a couple days ago I noticed my COWW I threw in the pot was casting very frosty bullets with lots of very tiny imperfections, like voids. So I stopped for the day. When the pot was cooled the lead was very frosty with biog cracks.
Fired up the pot the next morning, went inside and forgot I had started the pot already.
So was a good 20 minutes or so before I got back to it, and this is what I found.
What the heck ?

[bruce381]

flux it?

[khmer6]

Maybe a small critter left a surprise for you.
My first coww smelt I fluxed but obviously not enough. Lots of crud would float to the top of my casting pot after dropping ingots and stirring. But no where near that. Either resmelt or Flux in the casting pot

[sqlbullet]

I am not clear if you put clip on WW straight in the pot, or an ingot of cleaned lead made from COWW.

If it was the former, I have seen excess dross like this before when working with lead that is heavily oxidized. I had lots of dross when I used to work with little dental lead sheets which have lots of surface area per oz due to being a lead foil. Lots of surface area means more oxidation. I fluxed that a bunch then just scraped off and tossed the rest of the dross.

If it was an ingot, I have seen this once or twice. What happened in my case was the ingot was made near the end of a batch, when the oxidized dross had built back up some. The last ingot was only about 1/2 the mold, and had dross floating on the top. Like an idiot, I didn't think there was that much and when the next batch was ready to cast, I finished the ingot. Ended up with an ingot that looked good on the outside, but had a bunch of crud on the inside.

Regardless of how you got it, that is just dross. Flux really good three or four times, and then clean out what doesn't reduce back into your alloy.

Final thoughts...The frosty bullets are generally a sign of a hot mold/hot pot. Higher the heat, the faster the dross accumulates. Could be you just created a bunch of dross with a hot pot. That seems like a bunch of dross to occur that way, but especially if you dropped the poorly cast boolits back in the pot, it could just be dross.

[taco650]

Did you melt in some zinc WW's?

[docone31]

I get that. I use Kitty Litter for top layer. It gets the **** out.
Any rate, I put 1oz vegetable oil on the melt. I also run it on high. I then stir with a thin screwdriver. A lot melts back in and the crud goes to the walls. I also find layers of crud on the bottom. I scrap them and they float up. This is with clean ingots no less. It happens.
The Kitty Litter helps for sure. Catches impurities.

[Tenbender]

So a couple days ago I noticed my COWW I threw in the pot was casting very frosty bullets with lots of very tiny imperfections, like voids. So I stopped for the day. When the pot was cooled the lead was very frosty with biog cracks.
Fired up the pot the next morning, went inside and forgot I had started the pot already.
So was a good 20 minutes or so before I got back to it, and this is what I found.
What the heck ?
I melted pure lino from a pig and had a pot that looked just like that ! Pure lino is the dirtiest metal I have ever seen.

[hylander]

Thanks for the replies,
This was from already made COWW ingots.
I have never seen this happen before.
I cleaned it out and fluxed three times, it is looking much better.