How to overlay gold onto titanium?
I am making wedding rings for my fiance and me, and the design
we converged on is a titanium frame with ridges at the sides, and
22-24k gold in the trough, with a gentle rounding up in the
center of the gold.
I am having a machinist lathe the Ti parts to my drawings, but
now I have to figure out how to get the gold into the trough.
The suggestions I have heard are:
(1) Casting: make a plaster mold with the Ti part lying flat,
and pour the Au in through a small hole. --> that seems difficult
for me, but if it’s the best way, the I can pay someone to do it.
(2) Compression: start with an oversized gold band and sqeeze it
in from all sides into the Ti trough. --> possible rattle when
done due to “spring back” effect of non-infinite maleability??
(3) Soldering: Wrap a gold band around the Ti trough, and solder
it. --> The only issue I have with that (other than all I know
how to solder is Silver) is that, while Ti does have a much
higher melting point than Gold (1660 vs. 1064 deg.C), Ti,
according to the Handbook of Chemistry and Physics (CRC Press):
“…combines with oxygen at red heat…” and also:
“…is dimorphic. The hexagonal [alpha] form changes to the
cubic [beta] form very slowly at about 880 deg. C.”
Perhaps the cubic form doesn’t look or act much differently, or
the change is really very, very slow, so that the dimorphism
aspect is not a concern – but what about the oxygen issue?
Would the soldering have to be done in an innert atmosphere? Or
is a reducing flame sufficient?
Any responses to these questions would be most welcome
(especially in light of the rapidly approaching wedding date!!)