Plaster bandages, similar to those used by doctors for casts to protect healing bones, are used by crafters and artists to create masks, body casts and other sculpture. These bandages, sold by art supply stores, are strips of gauze fabric that have been imbued with powdered plaster of Paris and begin to harden within three minutes of being activated. Work in old clothes, near a ready source of water, to use a plaster bandage.
Fill a large bowl or basin with water and allow it to come to room temperature.
Cut the bandages in to lengths that are easy to handle and appropriate for the size of your project with scissors. For instance, 2.5 cm by 10 cm (1 inch by 4 inch) strips are practical for masks, according to Artlex, while 7.5 cm by 60 cm (3 inch by 24 inch) strips work best for body casts.
Cover any exposed skin or surface with a thick layer of petroleum jelly, if using a model or a mould, to prevent the plaster bandage from sticking.
Hold one end of the plaster bandage in each hand and briefly run it through the water so both sides are wet. The bandage should be immersed only once and for no more than five seconds.
Run your fingers down the plaster bandage immediately, with one finger on each side of the strip acting like a squeegee to remove excess water.
Apply the strip to your prepared model or mould. Smooth it with your fingers so it is flush with the skin of the model or the surface of the mould.
Wet another strip and apply, slightly overlapping the edge of the first strip. Repeat until you cover the entire area.
Hand off wet strips to a partner to apply to get the job done more efficiently. Change water if it begins to get cloudy or "creamy." Use no more than three layers of plaster bandages. Use cold water or add salt to the water to slow down the hardening process.
The plaster naturally heats up when activated by the water. Warn your model that they may feel some heat as the plaster sets.