What is this scummy stuff?

[Andy]

Oxides are a surface phenomenon. If they are indeed lead oxides from overheating they will be very shallow along the bottom and sides, but somewhat thicker at the top as all oxides that formed during the melt will have floated to the top when the ingots were poured.

Take a rasp or coarse file to a spot on the bottom of the ingots and let us know how far you go in before you get to clean, silvery metal.

You can't do anything like that cuz it's dangerous - even for the guys who wear space suits around lead.

 

[infideleggwelder]

In your case "fluxing like mad" isn't going to be detrimental to your pure lead/roof sheeting but if you ever decide to try a harder slug alloy such as WW, you have to be very careful with the fluxing-skimming operation. it is very easy to over-skim and remove the metal elements that add the hardness feature to your lead alloy. Actually good fluxing is supposed to alleviate some of the dangers of this, but poor fluxing habits can make it worse. Skimming crud from a harder alloy without fluxing first will immediately remove tin/antimony from a mix.

I like soft lead, and it`s hard to find in quantity. I really wished that would work for getting that stuff out of COWW