Types of silicone

[torri]

I've got some questions about silicone. I want to use medical-grade silicone for casting (use your imagination to guess what for!) but I'm having trouble figuring out exactly what type of silicone to use. I'm a bit baffled by the rather mind-boggling number of options that are out there, such as durometer and the different additives and colorants you can use. Everything must be medical grade, but additives and colorants do not usually specify. Also, what mold materials are compatible with silicone? I know silicone sticks to itself horribly, so does that rule out using it for a mold?

Any help or advice or slaps in the face would be greatly appreciated!

[Mostly Fantasy]

Usually, you can cast just about anything in a silicone mold (except for silicone). I've cast wax, castilene, plaster, gypsum cement, and all manner of urethanes. There are some medical grade pigments/releases, but they're not as readily available as the commercial ones, and are usually more expensive.