How do I remove release agent from my cured urethane casting if I want to prime or paint the casting?

Article courtesy of Smooth-On, Inc.

Removing a silicone-based release agent from your cured urethane casting is not easy. The most effective way is to sand blast or bead blast the surface of your casting. Sand blasting, however, removes a micro thin layer of the casting's surface. If not done properly, you can damage or remove fine detail.

  • Soap – Wipe or brush the casting with a soap that has high alkali content. Cascade™ brand dishwashing gel is highly alkaline and also contains baking soda, which is an advantage.
  • Solvents – Wipe or brush the casting with Acetone, Toluene, Isopropyl Alcohol or Mineral Spirits. Important: follow all safety precautions when using flammable liquids.

You can then prime and paint your casting.

Stop! There Is A Better Way.

If your goal is to paint your casting after demolding, read our article FAQ: How Can I Make Paint Stick To My Castings?

Disclaimer

This FAQ article is offered as a guideline and offers possible solutions to problems encountered during mold making and casting. No warranty is implied and it is up to the end user to determine suitability for any specific application. Always refer to the provided Technical Bulletins (TB) & Safety Data Sheets (SDS) before using any material. A small scale test is suggested to determine suitability of any recommendation before trying on a larger scale for any application.

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