Firm Mold Rubber: This is the mold rubber I sell. It is used to make simple two sided powder separation molds of flat non complicated objects. This rubber can also be cut if desired. It is ideal for beginners on up.

Semi Firm Mold Rubber: I would suggest Castaldo's Econosil. This rubber vulcanizes well and is best when cut apart with a scalpel. It is very putty like and forms easily around 3D patterns.