I have some vulcanized molds done in Castaldo Gold and some in
White, that are about 30 years old, They still have very good detail
and have all yielded several hundred parts, But they have been well
cared for, I have some that are 10 to 15 years old that were done in
Kerr White and their soft formula as well, These have not held up as
well as the Castaldo rubber, I have also used the Castaldo No Shrink
Pink embedded in Castaldo white label and are still going strong
several of these have had a few thousand parts run through, Down side
is they eventually need some type mold release, I prefer silicone
spray (in very moderate quantities) I have used the Castaldo RTV and
I like it BUT it doesn’t seem to have the durability of the
vulcanized molds, I have used Belicold RTV which I like, but is no
longer available, I also tried Rio’s Ditto formulas and while they
are very good at first the seem to deteriorate rather quickly, ( I do
watch my wax Temp. and pressure closely )I would say if a person is
going to only make 50 or 100 pieces then the silicone RTVs work
well, But I have to tell you, I LOVE the Castaldo Silicone
vulcanizing material , It so far has held up very well, over 1,500
parts on one run 3 molds, 500pcs per mold and no degradation of
detail, and as a good silicone should, requires no mold release. Plus
side of RTV is the range of things you can mold, I also like the
ability to mold directly off of a wax pattern or a plastic pattern
with 0% shrinkage, and that being said I really think there is a
definite purpose for both, but for high production Vulcanized for me
is better or so it seems
Kenneth Ferrell