Casting Question

[99whip]

I have just begun casting some lead round balls with a .375 Lee mould and a Lee melter, the smaller model that I think holds 4 lbs, not a bottom pour melter.  I am using some roofing lead which has been in my garage for about 30 years rolled up in the corner.  It melts down quick, using a roughly 700 degree setting, and I drop a very small piece of beeswax in to flux it, and then skim the impurities off the top.  The question - I seem to get a lot of lead oxide on top of the melted lead that would require a lot of skimming, thereby wasting a lot of lead.  Is that normal or is my temp to hot, not hot enough, etc?

Thanks in advance.

Whip

[Hewy]

The material skimmed could be from the age of the lead. When you say you" have just begun casting "
can I asume this is your first casting experiance ?
How doese the lead look just before you dip and pour into mold ?

[Hawg]

Once lead gets that white coating on it you don't get that part back. Ideally you should melt the lead into clean ingots before melting it in a casting pot. It's not really as big an issue with a dip pot as it is with a bottom pour.

[Hewy]

Further decription of the white material as Hawg said,
that stuff is impurities that rise to the surface and never returned to the molten lead.
Look up DROSS for better definition.
Don't worry about it.

[99whip]

It is my first time casting, yes. 

What I see on top of the melted lead in the pot is a yellowish almost gold looking skim on the surface that starts to form after I've fluxed it and skimmed the junk off the surface.  When I dip my ladle thru it the lead underneath is great and the balls pop out of the mould really shiny and look good to me.  But I'm constantly dipping through that yellow skim on the surface and if I clean it all off it just comes back again.  Seems to waste a lot of lead.  Maybe it's just really dirty?

Thanks for the tips.

[Captainkirk]

As was mentioned, the dross floats to the top and is quickly skimmed. When you cast it aside it hardens and looks like the garbage it is. Anything after that is natural oxidation and won't hurt a thing.
Good luck on your new venture. It's a lot of fun!