Two metal casting

I have a project for a pair of wedding bands in sterling silver and
18ct yellow gold (I know, I know but they wouldn’t have 18 white!).
Imagine 2 square interlocking strips that run parrallel for say
quarter inch then cross over and you get the basic idea. I can
fabricate one part and intend to cast the second, lost wax and
vacuum, onto the first component.

I assume I need to fabricate the 18 yellow and cast the silver but
am worried that I am still pouring silver in at or slightly above the
melt temp of the gold.

Will 18 hard solder stand up or do I need to cast the gold as well?
I am still happier fabricating than casting. Any pointers welcome.

Andy Parker, Agate House Lapidary
Ulverston, Cumbria, England
@Andy_Parker

Tel: 01229 584023

Andy, There is a specific protocol for casting ‘bi-metal’ designs.
It can be quite a job at the craftsperson level, though large casting
houses do it regularly.

I don’t know what your time schedule is but, if you have time, try
to obtain a little booklet called, ‘Bi-metal, Multi-metal Casting’ by
William E. Garrison, pub Magic Circle Corp, 714 10th Ave, E.,
Seattle, WA, 98102, in 1972. Maybe Amazon has it. While somewhat
crudely published, the booklet provides a great deal of information
on this subject at the craftsperson level. I am sure there must be
other tomes out there on the subject…this just happens to be in my
library.

Cheers from Don at The Charles Belle Studio in SOFL where simple
elegance IS fine jewelry! @coralnut1

I have done a similar job several times but with white and yellow
gold. I carved and cast the white gold portion of the ring first.
After casting, I coated the white gold part with boric acid solution
and heated it to the point of glazing. This was to protect the white
gold during the next firing. I then melted wax into and around the
cast gold piece then sprued and invested it and cast the yellow gold
part of the ring. After pickling, I flowed solder into the seam
between the two metals. I don’t see a problem using silver. It won’t
melt the 18K gold. The only problem may be when you try to flow
solder between the two metals. The oxidation of the silver may may
make this difficult. If it were me, I would refuse the job if they
won’t agree to white gold instead of the silver. Charge a lot, it’s
a pain in the butt job.

R.H.