Plaster of Paris Mixing Instructions

Updated April 17, 2017

Plaster of Paris is a popular tool in sculpture and can be used both as the art itself or as a mould for casting sculpture made from other materials such as bronze. Additionally, plaster of Paris is used in architecture and construction and by doctors for moulding casts for broken bones. Mixing plaster of Paris is fairly simple, though it may take some experience in order to get the consistency of the plaster just right. You can purchase plaster of Paris powder mix from most art supply stores (and just add water), but, in cases where you'd prefer to make the plaster yourself for a home project or craft, follow the instructions below.

Pour 1 gallon of warm water into the large bucket.

Pour either the glue, silica flour or regular white flour into the bucket with the warm water. Mix with a long wooden spoon or rod. There should be roughly two parts water to one part glue or one part water to two parts flour. So, for 1 gallon of water, use 1/2 gallon of glue or with 1/2 gallon of water, use 1 gallon of flour.

Add more warm water to the mixture slowly, mixing as you add the water. The water and glue or flour will develop into a soupy mixture, though using flour may prove easier and less slimy than using glue.

Stir the mixture until the plaster of Paris is smooth and the components are well mixed. The mixture should not be lumpy, as this will affect the appearance of the sculpture or mould.

Check the consistency of the mixture, depending on what components you used to make it. A glue mixture should be like a thick soup while a mixture made with the flour will be more of a paste. Now you can create your masterpiece!


If you do decide to purchase a premixed plaster of Paris powder, be sure not to inhale the powder at any point as this could be dangerous.

Things You'll Need

  • Old clothes or a smock
  • Warm water
  • White flour, silica flour, or glue
  • Long wooden rod or spoon
  • Large bucket (2--3 gallons)
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About the Author

Alissa Kinney is a full-time professional in the communications field, with an AB from Brown University and an MA in Writing & Publishing from Emerson College. She has years of experience as an editor and writer, and has been published in The Blue Doors, Our Town Brookline, Art New England and Body + Soul.