Non-porous surface to urethane: When working with urethane rubber, you must use a release agent to prevent the material from bonding with the casting surface. VFI has had great success using Chem-Trend MR-515 Aerosol with our urethane molding rubbers. You can also utilize a similar silicone-based release agent.

Porous surface to urethane: When working with a porous surface, it must be properly sealed before you begin pouring the molding rubber. VFI recommends creating a mixture of 80% mineral spirits to 20% petroleum jelly by weight to seal the surfaces. After applying several layers with a chip brush, spray a light mist of an aerosol release agent over the entire surface. VFI recommends Chem-Trend MR-515 Aerosol or a similar silicone-based release agent.

Concrete or stone to urethane: When casting concrete into a urethane rubber mold, VFI recommends utilizing one of Chem-Trend’s water-based releases specially designed for releasing concrete from urethane. For example, the CR-19597 is ready to use and can be diluted.

Check out our tech piece if you are having issues removing your castings from a urethane rubber mold. 

Also, VFI recently released a new series of Max Release Molding Rubbers that enhance the releasing characteristics for sensitive projects. Check out our press release for more information.