Casting Silver to Gold

I thought I’d try again to ask a question. I think last time my
request got lost in the melee!

I have done castings in sterling where I fabricate a bezel, then
embed the bezel into the wax ring and cast it. It worked like a
charm! I often like to work in sterling/gold combinations. Next
I tried fabricating a bezel in 18k gold, and embedded it into a
wax, then cast in sterling. The result was less than
satisfactory! The bezel basically disintigrated where it made
contact with the sterling. The ring (the sterling part) was
fine, but the bezel was detached.

I was wondering if anyone out there has done this sort of thing
successfully. I’d like to attach gold accents to cast silver
pieces. Without soldering them on, if possible. Does anyone
know why this didn’t work for me? Does it have anything to do
with the copper content of the gold merging with the sterling,
and weakening the join? It’s also possible that I overheated
the flask, as my burnout oven doesn’t have a computer to regulate
temperatures; and it often has a mind of its own, suddenly
getting much hotter without any warning!

If the different properties of molten gold and silver would
prevent doing this successfully, I’ll just do it the old
fashioned way, by soldering. But, if this can be done within the
casting, I’ll give it another try. I’m reluctant to try it again
if I know it’s a “no can do”.

Any suggestions?

Thanks,
Judith Marsh
In COLD NW FL!!!

Judith, I have not tried this with silver but with white gold
heads in a yellow gold casting, We have added 2% boric acid by
weight to the water before adding it to the investment (2%of
investment weight). It gave us a very clean casting. I think the
boric acid acted as a flux to allow the metals to bond. We have
not done it a lot but it has worked for us. Let me know your
results if you would please.

Thanks and good luck
Ray in sunny and cold southern Oregon

Judith: First, I would replace that kiln with a quality one.
Secondly, If this dosen’t cure the problem, Perhaps the tempeture
of the molten silver (was it sterling or fine?) might be too high
for the 18k gold. Frankly, I don’t have a lot of experience with
bi-metal casting but thought I’d make my sugestions.

Best of luck;

Steve Klepinger
P.S. It’s below zero with over a foot of snow in MI. Don’t complain to
me!