Yellow powder

[huntnfish72]

New to casting. I was casting today, took 15 minute break and returned and there was a yellow powder on top of lead about 1/8 inch thick. I threw wax in to flux but it wouldn't mix. What is it?

[Lizard333]

Oxides would be my guess. Skim and continue casting. I put sawdust in top of my melt to prevent that.

[huntnfish72]

Doesn't sawdust smoke like hell the whole time?

[RickinTN]

Sawdust won't really smoke any longer than wax of course depending on how much you use. Wax is a reductant, but not a flux. Sawdust is a flux. If you don't already have one get a lead thermometer and keep your pot under 750 degrees. I like to run between 680 and 720 degrees. The hotter you run the melt the easier it oxidizes and causes the layer you're talking about. I have a hard time getting the oxidation to return to the mix with wax or sawdust so I try to avoid it by temperature control so I don't have the problem.

Good Luck,
Rick

[Lizard333]

If you don't like the smoke, light it. It'll burn. What's left will prevent the oxidation.

[303Guy]

If you don't like the smoke, light it. It'll burn. What's left will prevent the oxidation.
Lighting it is fun. Just keep your head well back! Don't ask how I know.[smilie=1:

That yellow powder is not what you want to breath in and it does dust up easily. It's lead oxide (mostly) and is readily absorbed through the lungs.