I am using Home Depot clear silicone caulk to make the skin for the base of the models and for some intrinsic detail. I bought a case of silicone caulk-the smelly kind that off-gasses acetic acid. (I find the newer type that evaporates alcohol to be less effective). One of my previous blogs was about going to the cadaver lab to look at scalp and pubic skin under the microscope. I took two 16X16″ clay tablets to “sculpt” my notes in the lab since I couldn’t take even a microscopic section of human skin out of the medical school. Once the skin sculpting was completed, I made plaster molds of them.
I dry the plaster thoroughly and apply a coating of butcher’s wax. After buffing it into the plaster, I add a light coating of vaseline. The mold is ready for the silicone. For the 16X16 mold, I emptied three tubes of silicone caulk into a plastic container and add colorant. I bought silicone colorant from a prosthetics supply company (Factor II).
These colors are very saturated and just a little is needed to color a lot of silicone. By controlling how much is added, I can get a very realistic translucent color. I use a spatula to apply it into the mold. I found this to be a little tricky. I want a fairly even coating so I can add more highly saturated color as a second layer. I found that if I wait about 10 minutes, a skin forms on top of the silicone and with water on my fingers, I can push the silicone around enough so the layer is pretty even.
I will wait over the weekend to make sure the silicone cures all the way through. I will pull it out of the mold and assess whether I should add a second layer or not. Finally, I will back it up with either plaster or bondo.
One other application for colored I have found useful is to use it intrinsically in the insect casts to simulate internal organs or detail. In the case of the pubic louse, there are sensors that are connected by a network of channels. I used colored silicone to produce these. Tomorrow, I will use a scalpel to cut the sides of the channels cleanly.