Plaster of Paris is a general-purpose gypsum powder that makes an effective finishing or moulding material for many craft projects. Although there are some substitutes for plaster of Paris (including concoctions based on white glue or flour), plaster of Paris is a specific item with no pure do-it-yourself home substitute. However, you can buy the plaster of Paris powder cheaply and use it in many different ways to achieve your arts-and-crafts goals.
Mix your plaster of Paris at a ratio of two parts plaster to one part water. Other ratios are permissible, according to the manufacturer's instructions, for different applications. Soupy mixes might be better for things like handprint disks, while thicker mixes are better for surfacing a durable craft project.
Add liquid food colouring to the plaster mix for colour. Use 1 tsp of colouring per one cup of water.
Add small pebbles to the plaster mix for texture. Include one cup of pebbles for every five cups of plaster powder used. The pebbles should be very small with an average diameter of 1/8 inch.
Allow the plaster mix to set according to the manufacturer's instructions. Then, use your plaster promptly before the batch hardens or dries out.
In addition to mix-ins to your plaster of Paris mixture, you can add items to the surface of a completed project before the plaster completely dries. Cut-glass mirrors, larger shiny pebbles and pieces of ceramic tile can significantly enhance the quality of your project without diluting the plaster mix.
Some websites advertise "homemade plaster of Paris" instructions using white flour or white glue paste, mixed with water. These are not plasters, and using them instead of authentic plaster of Paris can lead to unfortunate results. While there is no homemade substitute for genuine plaster of Paris, there are plenty of creative ways to modify the base recipe for your specific purpose.