Jump to content
SASS Wire Forum

Green Powder In Pot


Capt. Montgomery Little

Recommended Posts

Howdy Captain -

 

Were you melting reclaimed shot? From your description, it could be arsenic. It's sometimes added to lead to slow the cooling process and allow the shot to form into a more uniform shape and make it a bit harder than pure soft lead.

Link to comment
Share on other sites

Not reclaimed shot but lead used in stained glass window production.

 

A yellowish-green oxide of lead can form on your pot walls. Make sure you are not casting at too high a temperature, flux with a good casting flux occasionally (I use either borax powser or parafin wax from old candles), and for sure watch out for any Calcium contamination from modern car battery lead alloys.

 

I understand that zinc chloride has often been used for fluxing lead soldering - zinc should not be picked up by the lead alloy, but it sure would be possible to get melting pot corrision from zinc cholride, so if you are the glass worker, you might use a zinc-chloride-free flux for your work.

 

Arsenic is fairly hard to oxidize once it is alloyed into lead alloy. Same for antimony. Tin can oxidize pretty fast, but then, preventing that oxidation is one reason to use a reducing type flux like parafin.

 

In general, keep your lead temp down below 800 deg F and you should not have much to worry about.

 

Good luck, GJ

Link to comment
Share on other sites

Thanks for the replies. It appears that the "powder" is coming from the "came" I used to melt. Just learned today that "came" is the lead strips used in stained glass work and if melted at a high temp, this will happen. Just flux w/parafin and it should go away. Never too old to learn something new and when I get old, I will appreciate that even more.

Link to comment
Share on other sites

Archived

This topic is now archived and is closed to further replies.

×
×
  • Create New...

Important Information

By using this site, you agree to our Terms of Use.