Natural gas or propane could be used as the gas. Obviously if you are
going to do this, you are going to have to be careful. But natural
gas plumbed into the iron pot will burn as it escapes from the pot,
but will not burn inside the pot as there will not be any oxygen
there.

Be careful and let us know how it turns out.

Dan


(Tim) wrote in message

The secret commercially is either a gas or flux cover. The latter
would be a salt 'alloy', such as equal parts sodium and potassium
chloride (can be had at the grocery store as "lite salt"; has to be
fused (mmm, salt ingots!) before use), with other select ingredients
to lower the melting point and improve fluxing action. For gas,
either an inert gas must be used (as lit Mg will continue burning
between two blocks of dry ice quite nicely) or sulfur dioxide works
fine, a bit of elemental sulfur dropped in the crucible holds it I'm
told. Stay out of the fumes...

Tim