Silicone molds

Looking at my crab claw I wanted to try make some silicone molds. An object like a crab claw wouldn't survive the heat used to set molds that are made in a vulcanizing machine. I wanted to make two part molds so it is easier to take the objects out of the mold as wax is injected into the mold and wax is fragile. I used clay, in a plastic container, to press my found objects into; I then poured in the silicone. Once the silicone had set I removed the clay, flipped the silicone over so the found object was facing up and poured the second half of the silicone. Silicone is made by mixing a base and catalyst, my ratio of catalyst wasn't exactly correct. The silicone set but was very soft and the clay also made the silicone very dirty which can be seen in figure 1. I ended up trying to make a solid mold and cutting it open as seen in figure 2, but I forgot to cut in a zigzag so that the mold has keys which helps hold the mold together when working with it.

Figure 1 - A two part silicone mold

Figure 2 - A silicone mold that has been cut open