Most jewellers that I have met treat rubber molds as an expense that
they are trying to save time and money on.
It always amazes me that model-makers will spend hours or days
making a beautiful model, almost a work of art in its own right and
then spend as little time and money on the rubber mold as possible.
This is backwards thinking, possibility because model-makers start
life as jewellers and therefore think in metal. They visualize the
end result more than the process.
The only reason for making a model is to be able to make the mold.
It’s the rubber mold that has value, not the model. Model-makers are
in fact mold-makers or at least they should be. It’s the mold that
makes the waxes, not the model. The art of mold making is probably
the most critical and under appreciated jewellery making skill.
Making great rubber molds can involve a lot of testing, development
and ingenuity. Difficulties in filling and pulling waxes, casting
defects and downstream assembly and polishing problems can require
changes in the mold. Most bench work in a shop that uses castings is
repair work. These jewellers are repairing the work into existence
not making jewellery. Most repair problems should be dealt with in
the mold. The design and development process is focused on improving
the mold. It takes a lot of mold making experience before you can
visualize the model inside the mold and see in your mind’s eye the
best way to cut it. I would even suggest that most models are not
designed to make molds or even for casting, polishing and assembly.
The whole process is like playing chess, you have to think ahead.
Most of that thinking bottle necks at the rubber mold.
With these thoughts in mind I would like to suggest that you attempt
to make your molds as thick as possible. Give the rubber as much
rigidity as you can, even for very small parts. Don’t hesitate to
make your mold over again. The small cost of rubber is nothing
compared to the value of the mold and the precision waxes that it
produces. By the way, why do we put our least experienced people in
the wax and polishing rooms?’