When casting polyurethanes, using a barrier coat can greatly extend mould life, where in some cases up to 200 percent. Prior to casting, the barrier coat should be sprayed into the silicone mould.

When removing the cast part from the mould, the barrier coat becomes the outer skin of the casting. Note that this type of barrier coat is different than the barrier coat mentioned in Techniques to Prevent Inhibition.

Reconditioning can be accomplished by burnishing a low viscosity PDMS fluid into the surface. When the mold is put back into use, any excess fluid should be removed from the surface. This is necessary to ensure that the cast parts will be paintable. Non-wetting or fisheyes can occur on the surface of the cast parts if all excess PDMS fluid is not removed. To remove the hardeners, plasticizers and other materials that leach out of the casting material, you can use a bake-out. Bake the moulds for longer times at lower temperatures, such as 90°C (200°F) for six hours to overnight, or at higher temperatures, such as 120°C (250°F), for one to two hours.