Materials improve with time. I have seen a few posts which suggest
that RTV in general is not as strong as vulcanized natural rubber.
That was an accurate generalization eight or more years ago.
Although we manufacture natural mold rubber, back in 1993, I saw a
clear need for a high tear strength RTV silicone. Silicones were
noted for very low tear strength. That was true of both the RTV and
the heat cured silicones of the day.
It took us about a year to develop the characteristics jewelers
needed. We introduced high tear strength heat cured silicones (4X
Gold), and a little later, Akron RTV Silicone (clear).
Today, a lot of jewelry manufacturers are using Akron RTV Silicone to
make production molds directly from original waxes, thus completely
eliminating the model making step. Silicone RTV is initially costly,
but it makes a permanent mold (unlike the less costly urethane RTV
which tends to revert over time, especially in moist regions).
Manufacturers find that skipping the model making step easily
underwrites the higher cost of the mold. In addition, throughput
increases with silicone because of the easy release character. There
is very little tinkering involved in getting the wax out of the
mold. Some folks claim to have doubled speed at the pot.
I am available at any time to answer questions relative to how
Silicone RTV can best be used. As with any material, there are some
limitations, but it is a new day and these products currently save a
lot of money for the manufacturing jeweler.
Zero-D Products, Inc.
38285 North Lane. #103
Willoughby, OH 44094 USA
fax 440 942 2130