Making a Brush‑On Mold of a 3D Hollow Model


The Challenge: Filling the void on this hollow puma head so an efficient brush-on mold can be made.

Making a mold of a hollow model presents a challenge to the mold maker. The void must be filled as the primary step of making the mold. A "mouth core" will be used to fill the mouth void and a "mold plug" will be employed to duplicate the hollow space which runs through the original model.

This challenging mold of a puma head will be made using Smooth-On's Rebound® 25 brush-on silicone rubber. There has never been an easier to use brush-on silicone rubber than Rebound 25. Mixed 1A:1B by volume (no scale necessary), Rebound 25 self-thickens and will hold a vertical or inverted surface, and will cure to a soft, flexible rubber (Shore 25A) that is incredibly strong. Three to four layers is all that is necessary to make a strong, durable production mold for casting wax, gypsum, concrete or resins (urethane, polyester, etc.) and because Rebound 25 is a platinum silicone, it will last for many years in your mold library.

Materials Used in this Tutorial

Step 1: Preparing Your Model