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How to Mold Polyurethane

Polyurethane is a flexible, versatile plastic that can take either a soft or rigid form. It has a variety of industrial uses, ranging from cushions and car seats to refrigerator and roof insulation. Crafters can purchase small amounts of polyurethane from art supply stores. The product comes in two separate liquids, Part A and Part B, that the crafter mixes together, and this liquid turns solid when dry. Artists can easily mold the plastic into any shape or around any object, creating a transparent casing.

Things You'll Need

Mold
Mold release agent
Polyurethane liquid
Gloves
Mixing container
Stick
Colorant

Instructions

- 1
  Select or make a mold for your polyurethane. This should be the inverse of the finished shape. Spray the mold with a mold release agent to prevent the polyurethane from becoming stuck to the mold.
- 2
  Pour Part A and Part B into a mixing container, using the ratio specified on the bottles. Stir the solution slowly with a stick to prevent the formation of air bubbles. Add colorant or other materials, such as flakes of metal or confetti, depending on what you want for your project.
- 3
  Tip half of the mixture into your mold, pouring slowly to reduce the likelihood of forming air bubbles. Gently tilt the mold to distribute the liquid and remove air before adding the remaining mixture.
- 4
  Consult the label on the polyurethane liquid for the time needed to harden. Remove your work from the mold when completely set.
- 5
  Bake the work in an oven at a low heat for a few hours. Alternatively, leave the work to finish hardening at room temperature for a few days. The exact amount of time needed will vary, depending on the product.

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