Taking the Mystery Out of How to Make a Concrete Sink Mold
Step 6: Preparing, Casting & Demolding Concrete
Apply In and Out II® release agent to all surfaces. Place the mold between the boards and secure. Place the mold on a vibration table and fill with concrete. Allow the concrete to cure for 24 hours and then demold casting. You've created a perfect concrete reproduction of the original! The rubber mold is ready to be cast again.