I made some tooling to form the core of my composite propellant grain. I went to the local plastic shop to buy release for fiberglass. I cast the propellant in the casting tube with the released core tooling in place. After the propellant cured I tried removing the core tooling. It was bonded in quite well. I finally had to burn the grain to get the tooling out. That release I used for fiberglass seemed to act like a good glue with the composite propellant. I had done this once before without the release and with some pulling was able to get the tooling out. But with the release there was no way it would come loose.
What is a good release to use for casting composite propellant?