Check out this chart for recommended sealers and release agents...

Ease Release® 200 is an excellent general purpose AEROSOL Release Agent for making molds and casting parts. This product will release urethane rubber, urethane resins, polyester resins, RTV silicones and thermoplastic polymers. Ease Release® 200 is effective on urethane, silicone and metal molds.

The prefect agent for releasing:

• Polyurethane Rubber From Original Models
• Polyurethane Plastic From Urethane Rubber
• Silicone Rubber From Original Models
• Silicone Rubber From Silicone Rubber
• Polyurethane Plastic From Silicone Rubber

NOT FOR USE WITH URETHANE FOAMS. For releasing foams use Ease Release 2831