Take a oil based clay and make your sculpture. Then take knife and cut it straight in half verticly. Then take a plaster epoxy and cast it over each half. Let it dry. Now fasten the 2 halfs together (super glue will probebly work) but the best way (not the easyest way) is to drill tiny holes in the sides and use little bolts to keep it together. Then pour the latex into the mold and let it dry all the way through. When it is dry disassemble the mold and you have it. This can now be painted with accrylic paint.
all the materials can be bought and ac moore or www.monstermakers.com
I see I am not being clear. What you said makes sence - but its for a more complicated mold/casting project than what I am doing.
Mine is a one piece horzontal mold. If you look at the second picture you can see the part that was cast (in resin) using a sculpie mold. I actually have a "blank" that makes an impression in sculpie or clay or whatever. Then you pour resin into the impression. The back is flat - its supposed to be an emblem you can paint and also back light. Now, originally I casted in plaster into a sculpie mold (BTW - for those that don't know, Sculpie is a polymer clay that can be cured - I didn't cure it). It worked great and I could actually reuse the mold 2-3 time before the sculpie got distorted. That was prototyping. Plaster is too brittle to use as a casted part (although, I am considering it as a mold material).
Next, I casted resin into the Sculpie. I got the whitish part you see in the second Pic. This destroys the mold - no biggie - I just press another with the blank. The problem is, the part has sculpie all over it that is hard to remove (see the white stuff in the eyes?). Clay does the same thing, but not as badly.
So, I went with insta-mold. It make flexable molds that don't stick to resin like clay or sculpie.
Two problems - it bleeds water (its water based after all) and this give the surface of a casting an "icy look" and washes out details. The resin actually begins to float in the mold. I did some tricks and got some OK casts, but the mold shrank becasue of it. Also, the water stops the curing process at the surface of the part. My 2 hour resin took overnight to cure. My regular resin has taken 3 days. I'm not that patient.
So what I was gonna try is a latex rubber material to make the mold. This is reverse casting really.
My blank will not work for this (its big and bulky). So:
first cast a part in sculpit or clay that is "perfect" (the one in the picture has some imperfections)
then mount the part in a small box face up.
Pour the latex over the part and wait for it to set.
Pull the latex out and you should have a block of latex with an impression of the part in it.
Then I can hopefully cast resin into the latex "mold"
Problem is, latex material smells very bad!!
If the latex fail I will think about plaster. Plaster is such a pain though.
Thanks for the interest - but what you are talking about is for more complicated sculptures than mine.
PS, I put your name in the MRL for the soldering thread.