Melted silver porosity

[marcos9999]

I've melted some silver filings into a rod, which I then hammered and shaped into a ring. But to my surprise, after a high polish I've fond lot's of porosity deep within the metal. Filled away to no good end. What is the best way to remove these air bubbles when melting. Borax? I've only used flux for this project.


Thanks for your input.

[china]

When melting always use borax, helps remove?prevent impurities contaminating the metal, however in your case I would say it was more than likely , you metal was too cold, a few points;
preheat properly conditioned flask (glazed)
preheat properly conditioned mould (oiled)
heat metal to correct temp. ( metal should appear to spin)
keep flame on metal as you pour

[art925]

When melting always use borax, helps remove?prevent impurities contaminating the metal, however in your case I would say it was more than likely , you metal was too cold, a few points;
preheat properly conditioned flask (glazed)
preheat properly conditioned mould (oiled)
heat metal to correct temp. ( metal should appear to spin)
keep flame on metal as you pour

All of the above, plus remelting silver with a strong flame can also introduce oxygen to your mix.

[marcos9999]

Thank you for your great input! Just bought borax and will try again.11909