What will Silicone not stick to?

Generally, silicone RTV mold making rubber does not stick to anything, and nothing will stick to it. The exception is that it will stick to itself, other silicones, silica, and glass. In order to protect the prototype and remove the silicone mold easily, you can brush release agent upon the model before pouring the silicone. Release agent can be soap water, detergent water or Vaseline. 

Silicone RTV mold making rubber may soak into a porous surface and lock in place. This is often the case when making a mold from a wood pattern. To prevent sticking, seal the wood so the silicone can’t soak into it. Krylon Acrylic spray is a good choice. It is compatible with just about any substrate or silicone rubber. Silicone doesn’t stick to Krylon Acrylic. Petroleum jelly can work well as a wood sealant also.