I want to mold an object

Depending on how accurate "accurate" has to be and what material you are
using for the prototypes,
Latex (sold as molding compound at places like Hobby Lobby and some
hardware stores) will make accurate
soft low temperature molds in which you can make copies with plaster,
casting wax or, perhaps the best, casting resin which is also sold at the
same places. From places like MCS (www.mcscdirect.com) you can get
casting metals that melt below the boiling point of water and can be cast in
the latex, but cost a small fortune.
You can use the wax copies to make lost wax molds in plaster or
investment for casting in lead, zinc, or aluminum at more or less reasonable
temps and glass and brass at higher temps.
RTV is a casting rubber developed by GE that is available in liquid (and
paste but you don't want that) that will stand temps to molten lead for
several castings and perhaps molten zinc at higher temps.


--
Mike Firth
Hot Glass Bits Furnace Working Website
http://users.ticnet.com/mikefirth/hotbit46.htm Latest notes

"Jana Cole" wrote in message
...
I a not really a crafts person, but I am trying make a prototype of a
toy that I have a patent pending on. I have made one in polymer clay
by carving the clay after baking it.

Anyway, I wonder if there is a way to create an accurate mold that I
can fill repeatedly with a material so I can make lots of prototypes.
Something I can do in my garage.

The toy is sperical, hand-held. I would need to make the toy in
half-spheres and glue it together. Small cavities would need to be
created inside the half spheres that match exactly when the spheres
are glued, or otherwise joined, together.
Also, I need to make a thin, long slit through the sphere for a coin
to pass through.

Any ideas on how this could be done with accuracy?

j in San Francisco

Latex is really not the optimal material to use and will not hold up all
that well. It is rarely used anymore as there are many other products that
are easier to use and will hold up over the long haul. I would recommend you
go to http://www.polytek.com or http://www.smooth-on.com. Those two
companies have a host of "rubber" products that you can research. They also
have downloadable information that can be very helpful in understanding how
to use their products.

Depending on how accurate "accurate" has to be and what material you are
using for the prototypes,
Latex (sold as molding compound at places like Hobby Lobby and some
hardware stores) will make accurate
soft low temperature molds in which you can make copies with plaster,
casting wax or, perhaps the best, casting resin which is also sold at the
same places. From places like MCS (www.mcscdirect.com) you can get
casting metals that melt below the boiling point of water and can be cast in
the latex, but cost a small fortune.
You can use the wax copies to make lost wax molds in plaster or
investment for casting in lead, zinc, or aluminum at more or less reasonable
temps and glass and brass at higher temps.
RTV is a casting rubber developed by GE that is available in liquid (and
paste but you don't want that) that will stand temps to molten lead for
several castings and perhaps molten zinc at higher temps.