I made a ring in wax and have mounted all the diamond accent
stones. I read this was the new latest and greatest way to get
castings done - until I called my casting company. They told me
this is 'old school' and nobody does this any more.
Latest and greatest 25 years ago, perhaps. Not any more. But it’s
still done, especially with lower end high volume production, such
as what’s common in India and China and other such places. Some of
those folks have it down to quite a science. Done poorly, the result
is absolutely useless crap jewelry that shouldn’t be sold to anyone.
Done right, and it can take a careful look by someone who knows what
to look for, to determine that the stones weren’t hand set. But
doing this right tends to be something that normally takes some trial
and error to get the molds just right. It’s not generally a "one off"
sort of method, though of course it can be if you wish. But doing it
that way, especially if you’re chosing this method because you are
not confident in your normal stone setting skills, may be a mistake.
Better, in that case, to job out the setting work to a skilled
setter, I think.
The trick with stone in place casting is that this isn’t just a
matter of popping your diamonds into the wax and using some special
magic to have it cast. The casting operation is almost the easiest
part of it. The real key to whether it works is the design of your
mounting and how the stones are set in the wax. Done right, they are
not set as you would do in metal. You want less contact between
stone and wax than you’d want setting directly in metal, to reduce
both heat shock to the stones and the force of shrinkage stresses,
and also so that there is enough contact area between the stones and
the investment on both top and bottom of the stones, so they are held
firmly in position. Done wrong, and you can burn or break stones, or
have them slip out of position during burnout or casting. The result
of all this is that if there are any errors in the design of the
mounting for this method, the stones will not stay secure. It’s not
as simple as it sounds.
Hope that helps