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RTV mold storage

Having just completed my first sucessful attempt at making a mold I
now must ask , what is the proper way to store the finished mold and
what shelf life should I expect ? I ask this as the completed mold
has a oily film which will not stop appearing on the surface as well
as in the mold cavity , what should I clean this with or should I
clean it before future injections?I used the Castaldo Quick - sil
RTV Jewelry Molding Rubber. Thank You Timothy

Dear Timothy,

This is michael Knight at CASTALDO=AE. 

The appearance of an oil film is a minor annoyance with our new

Quick-Sil RTV rubber. It is normal and harmless. Soap and water
will clean it off.

As for storage-- away from heat and light is the best ideas -- a

closed box, drawer or envelope is all you need.

Hi Timothy, Congratulations on your first RTV mold! I have been
making molds for longer than I care to remember. I strongly believe
in the quality of the Castaldo line of mold rubbers and products. The
Quick-Sil compound is one of the tools in my mold “tool box”. As a
production caster to many fine jewelry artists I prefer the natural
rubbers for long term reproduction. I have seen Castaldo Rubber molds
over fifty years old and still working great. I use the Liqui-Cast
RTV on one of a kind carved waxes and pieces that need a mold with 0%
shrinkage (keep in mind that some injection waxes can cause more
shrinkage than some mold rubbers). As to the storage and maintenance
of the Quick-Sil…you can clean it with a cotton ball and a little
rubbing alcohol and as with any mold, store it in a cupboard or
drawer out of direct light of any kind. Some people put a rubber band
around their molds to keep the halves together, however this is not a
good practice. This can sometimes bow the mold enough to cause
injection problems. I wanted to mention Castaldo’s vulcanized silicon
mold compounds. Having made brown molds for so many years it is
refreshing to see the rainbow assortment of day glow rubber! Don’t
underestimate the power of a little color to brighten your day! I
have talked to folks who use the different colors to categorize the
models…pink for earrings, green for rings, etc. Another good thing
about the vulcanized silicon compounds is than they are easy to cook
in a toaster oven with a couple of thick steel plates and a couple of
C clamps if you want to experiment with the stuff before shelling out
a wad for a vulcanizer. There are brochures in every box that detail
the process. If you are used to cutting natural rubber take caution
cutting a silicon mold. The blade moves much faster through the
silicon. John, J.A.Henkel Co., Inc., Moldmaking Casting Finishing

Contact Polytek in Easton , PA for on RTV mold making
materials and what to expect. They manufacture the stuff in many
different type. They have a great booklet that explaines all their
products. They also offer a 2 day class on their products.