Or much of anything else most of us are familiar with - they have
their own technology, by and large. Like others, we have found this
to be one of the toughest nuts to crack. We have some certain
clients that just insist on molding lettered rings, and other
things, and then they hit everybody with a wax pot trying to get a
single wax or two.
I’d forgotton about it when I wrote my first reply, noting the metal
molds and all, but Dave Mereski’s suggestion does indeed truely solve
the problem, and at an acceptable cost. The system consists first of
making your molds of what I seem to recall is a standard transparent
silicone RTV or cold mold material. Several are available I think.
The main innovation is the mold material itself, which is used
instead of injection wax. It’s a liquid polymer that you can pour
into the mold (clamped shut during this). Because it’s liquid, you
can allow it to fully fill at your leasure. Bump it jog it, or
whatever. You might even be able to vacuum it (not sure of that) When
demonstrated, the method was to put the mold in the bottom of a
stocking or bag or something like that and swing it around in a
circle, so centrifugal force would cause the resin to fully fill,
and any bubbles to be dislodged and float “up” to the sprue. The
transparent mold lets you carefully examine the mold to be sure it’s
filled, visible because the resin is nicely red colored. When you’re
sure it’s filled, you then expose the mold to sun lamp type bulbs,
and the ultraviolet light cures and solidifies the resin. When that’s
done, you remove your casting model which is now a durable and
accurate resin/plastic model instead of wax.
While purchasing this system requires mold material, a standard
glass side RTV type mold frame, the resin, and the sun lamp bulbs,
this whole system, last I saw it, cost a couple or few hundred, not
the thousands you’d pay for a vacuum wax injector. And it really does
make even the most complex mold fillable. At that point, your limits
become not whether you can get the mold to fill, but rather if you
can manage to actually cut a decent mold in the first place to allow
the original model and later, the resin models, to be removed from
the molds. But you don’t need to cut vents in the mold, and the resin
models are more durable than wax, so if you can pull the original
metal model from the mold, likely the resin one will come out too.
As I recall, it was marketed in response to some of the rapid
prototyping methods that can produce such detailed and delicate
models that people can find it hard to get proper casting wax models,
and this system solved that.
It does, of course, then cost more per resin/wax model that
injection wax, and is slower than normal wax injection, but like I
said, from what I saw, it’s very effective. And problems of wax model
shrinkage within a rubber mold are also eliminated.