Also, can you fuse 18K standard alloy? I would like to fuse an
18K gold bezel and then fuse the bezel to base of sheet 18K.
Would that work? I'd try it out myself but don't feel like
experiencing another meltdown :-)
great questions! here are a few answers, just off the top of my
head. zinc is added to gold alloys to retard oxidation, as a
grain refiner, and to generally 'help' the casting process. since
it is the lowest melting component it likes to evoporate while
one is melting a karat gold charge for casting. this is the
reason most casters say to use at least half new metal. there are
now 'gold replenishers' available that i suspect are nothing more
than zinc or metal oxides to enable one to use a gold charge of
all old metal. there are however, metal suppliers that use other
metals as a grain refiner such as indium. i'm not sure, but the
addition of zinc increases the interval between liquidus and
solidus. well, anyway that is a few reasons why they put that
zinc in there.
the reason why one wouldn't want zinc while fusing,(though one
can fuse gold with zinc in it) mokume-gane or granulation is that
the zinc gets a little more excited than the other metals when
they all get hot. it melts first, so when the rest of the alloy
gets ready to interface, the zinc has already traveled around and
made a mess. as in mokume, it can travel through many sheets of
ones laminae, and possibly cause puddling. i think one of the
principles of fusing is to narrow the interval of liquidus and
solidus. i.e. it's best to have a more definite melting point vs
a range of melting to enable one to create a better joint. a
great example is platinum, its melted or it isn't. no 'pasty'
interval, a clean fuse.
it is most definitly possible to join your bezzle with a plate
using granulation methods.
hope this helps,