all you need to do is to insure that the crucible is well glazed
with borax if using a fused silica/clay crucible
When making gold/nickel alloys, the first thing to do is to lock
your borax in a safe. You are not going to need it. The only flux
used is boric acid. Dedicated crucible is of paramount importance. If
new crucible is used, then it should be glazed with boric acid.
Large torch is needed because only yellowish part of reducing flame
envelope should be used. I keep torch 2 feet away from crucible while
melting to insure that there are no free oxygen present.
While some stir alloys, I do not. When metal is liquid I shake
crucible using small horizontal movements of my left hand. The right
pouring temperature is when metal has shape of fresh egg yolk. I cast
my alloys twice to insure proper mixing. After first cast, ingot is
rolled very thin; cut in small strips; and strips are melted again.
Nickel golds must not be quenched, only air cooled.