Lay newspaper over your work surface to protect it from any incidental drips or spills.
Pour two parts of white glue into a large bucket or bowl. Beat with a spatula to aerate the glue.
Add one part of warm water to the glue. Stir the mixture until it develops a paste-like consistency and is free of lumps.
Check the consistency of the mixture. The plaster of Paris preparation should be fairly watery, about the same as a thin soup. If the mixture is too thick, add more water and continue stirring until lump-free.
Use your plaster of Paris preparation immediately for best results. Soak strips of paper in the mixture for making papier-mâché crafts, or use your plaster of Paris preparation in mold-making applications.