The use of an elastic material such as silicon achieves a high degree of exactness in the molding of the surface. The soft negative has to be supported with plaster shell molds.



To produce the negative, three to four layers of silicon are applied. The layers have different colors (white and gray in the picture).

If it is not possible to take apart the original model, the silicon mold is made in multiple segments that have to be aligned is such a way that no undercuts arise and the form can later be taken apart without difficulty. In order to strengthen the silicon for separation, flat bands of silicon are used for reinforcement (white in the picture).