Which RTV material do you like?

Which RTV material do you like? I have been using the same room
temperature vulcanizing mold making material for quite a few years.

I am not unhappy with it, but I would not know if there is a better
one unless I instigate. I do not want to buy a number of them and
experiment and so I figured that asking the collective knowledge here
would be a good place to start.

Do you have a favorite? Can you tell us all about it and why so that
we can benefit from your knowledge?

Thank you,

I like the Silicon RTV’s, easy source for me is Douglas and Sturgess
in San Francisco area. I use both the tin and the platinum cured
rubbers, the tin is a lot cheaper but has a shorter mold life (about
10 years). One MUST keep all mixing tools, containers, mold frames,
etc. separated into tin and platinum as materials used with the tin
will contaminate the platinum and the platinum will then have a
soft, gooey layer right next to the item. RTV silicon will tear more
than other mold RTV’s but the surface quality is top notch. if
tearing is going to be a problem when demanding the item being
molded, another way to go is heat vulcanized silicon or one of the
other materials. Heat vulcanized rubbers are the toughest of any and
they have a very long mold life…

I have yet to find an RTV that has all the qualities I am looking
for, so I use the particular for the particular job. I know some
folks who use silicon caulk as a mold material but I don’t recommend
it unless you are in a very particular situation and that is all
that is available.

Hope this helps a bit. I am curious to see what others think/use.

john dach