How is fusing pure gold different than fusing fine silver?
It's a lot easier, at least in my opinion. Silver, when molten,
tries very hard to dissolve atmospheric oxygen, which it then spits
out again upon cooling. The result is a tendency to rather rough
surfaces. And weld/fused joints in file silver sometimes have a
distinct tendency to be brittle, perhaps due to the above mechanism.
Gold on the other hand, doesn't do either one. Pure gold fuses
easily and cleanly. Since gold is not a superb thermal conductor as
is silver, it takes less heat to fuse a joint, and it's much easier
to control the melting to just the area being worked, while in silver
you're always a hair's breadth away from the whole thing melting...