Subject: Casting in Rubber: Success

From: [email-masked] (Cori Stewart)
Date: 10 Apr 1995 01:45:42 GMT

THanx to all who gave me information here and through e-mail.  With a bit 
more searching, I came up with some info, that might interest some of you:

I called around to some hobby stores, specifically looking for those who 
dealt in metal miniatures used in war game.  I had heard there were kits 
available to make your own 'tin soldiers' at home and that the molds used 
were rubber.  Sure enough there were, and there were kits available ... 
the prices however were far too out-of-rage for experimentation.

I came to call one store in Hamilton, called J&F Hobbies.  He invited to 
show me how he does it and so I took the bus up there and glenaed some 
interesting tid bits.

He uses an RTV rubber that is normally used for sealing car gaskets and 
such.  As many of yo may know, there are quite a few different grades of 
this 'caulking' on the market.  One specific grade, that is apparently 
ideal is called "copper" (as it is orange in colour), while the others 
are rated red, nblue, white, clear etc...

What he does, is work up the initial mold in this copper RTV caulking, 
but as it is expensive (about $8 a tube), he uses regular clear silicon 
indoor outdoor caulking to fill the rest of the mold, after the initial 
RTV cualking has set in about ... oh 1/4 inch around the model being 
cast.  Then, he reinforces the whole lot with a plaster filler to help it 
keep it's shape.... If you want full directions, i can post them or send 
them to you.

Another point that is interesting, since there has been talk of 
releasants here ... he uses a 50/50 vaseline-mineral spirits concoction, 
which he deems as a 'mucousy' consistancy.

Now, I haven't actually cast yet using this method, but I have seen some 
of his casts, which are reasonable for what he is doing and perfect for 
what I'm doing.  I've only so far made the mold, and it is in the process 
of curing.  His method takes preparation spanning over about 5 days 
before you have a mold you can use because the stuff takes a while to 
cure. 

I did however, take a look at the mold (I peeked) and the detail of my 
pendant is exquisite.  Plaster for htis particular piece would have been 
a disaster.  I'll let you know what the final outcome was and also what 
things are to be watched out for when casting, preparing etc.

Thanx again

T. Shawn Johnson 
(using Cori's account)