After the first half of the silicone molding cured and was ready to be removed, I pried it out of the clay outer molding and trimmed it up. Then, I added some indentations to the first half molding so that when there is no hammer, the two halves of the mold will join seamlessly. Next, I added a retaining wall around the upper half of the mold, to hold the second half of the silicone molding. Then I mixed and poured the second half. Ideally, a thin layer of soap should be sprayed on the mold to enhance their seperation, but I forgot (this is, after all the prototype).
After that cured, i removed the walls. I mixed up a batch of plaster of Paris, and then poured it on top of the silicone molds. This will allow the silicone molds to have a rigid form to stick to. Ideally, a layer of vaseline or cooking spray should be used to enhance the seperation of the layers (but I forgot that again).
The results of the first molding
First half of the silicone molding trimmed and indentations made
retaining wall for second molding
overhead shot ready for second half of the silicone molding
Mixing the silicone
Letting it cure.
second half of the silicone molding without retaining wall
Mixing the plaster
pouring the plaster o' paris
Letting the plaster mold cure.
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