In this lifecasting tutorial video, we demonstrate lifecasting a head using Body Double Silicone Rubber from Smooth-On.
Alginate is used to make a lifecast of a face. Alginate is a flexible material and needs a support mold to keep it's form. Plaster bandage is used to make such a shell. If you want to make multiple castings out of a mold it is advisable to use a skin safe silicone to make the negative of the face.
After the alginate powder is thouroughly mixed with water you have a few minutes working time before it sets. The working time is influenced by the (water) temperature and the mixing ratio. Our FormFX lifecasting alginate is, contrary to dental alginates, specially formulated for making body casts and gives you a longer working time. Mix small batches at a time. Take care to put the model at ease and DO NOT BLOCK THE NOSTRILS !!!
The materials used and some alternatives.