I also sculpt smaller creatures for a variety of jar sizes. I am only limited by the size of the jar and opening of the jar mouth how large or detailed the final piece might be. The sculpting process is very similar as creating shadow box figures with the one exception that these creatures have little to no limbs separate from their bodies to aid in the sculpting process.
The baked sculpture becomes the master that a mold will be created from. foam core is used to build the walls and base that will become the sides and base of the mold. Hot glue holds the pieces together and the master is coated with mold release to help aid in the silicone not sticking to the master sculpture.
Two part resin is mixed and poured into the silicone mold. A vacuum chamber is used to remove as much air from the resin as possible prior to pouring in the mold. This is necessary to prevent air bubbles from forming during the casting/curing process. The resin is left to cure for approximately 10-15 minutes. Once the resin is cured the reproduction of the original sculpture is carefully remove form the silicon mold. It is extremely important to take time in this entire step to guarantee the best facsimile of the original as possible.
After the initial test cast as many of the original sculpture can be made using the silicone mold. The resin can be tinted a certain color or left white depending on the painting and finishing process of the cast pieces. Eventually the mold will 'burn out' and the duplicates pulled will lack alot of the detail seen in earlier duplicates created. When that happen and new mold can be created from the original piece and the process starts over. That is why it is so important that care is taken during the molding making process to not damage the original sculptural piece.
Every cast piece is washed and dried to remove any residual mold release material. Then any seams or irregularities are sanded smooth prior to adding the base or primer coat. From there color is added in light even coated till the correct effect and texturing is achieved. Many times a 'paint master' is first created to use a painting guide for all subsequent pieces painted in the same style or method. Due to the possible high volume of pieces created an airbrush is used during the painting process to help speed the process up. All pieces are allowed to thoroughly dry and then a final coat of clear is applied to seal and protect the painted surface.
Once the clear coat has dried thoroughly each piece is mated up to their respective jar. Each jar have been aged through a variety of processes to simulate the aging of a scientific specimen jar long forgotten on some museum shelf. Jars are sealed and readied for their reproduction labels.