Plastiline Clay

Q: What is plastiline clay and how can I mix my own?

A: Plastiline, or oil-based modeling clay, is basically clay powder mixed with oil and wax instead of water. Its advantage over water-based, or potter’s clay, is that it stays workable for long periods of time, instead of drying and shrinking as it does so. One recipe is as follows:

  • 10 lbs. microcrystalline wax
  • ½ gallon #10 weight oil
  • 4 lbs. plain automotive grease
  • 25 lbs. dry clay powder (such as Kentucky ball clay)

Melt wax, oil, and grease together in an electric frying kettle; stir clay in slowly once melted. Pour into shallow microwave-safe plastic containers, or into a wet plaster mold.

This basic recipe may be modified for specific applications. One variation I have worked out uses beeswax for part of the wax component, substitutes petroleum jelly for the grease, and purified mineral oil for the #10 weight motor oil. This smells better, and doesn’t have a problem with the rubber mold compounds I use, like most proprietary plastilines do. Varying the proportions of the constituents slightly will yield harder or softer clays.

by Andrew Werby