Creating a 2‑Part Silicone Mold


Mold Max® 25 is the newest member of Smooth-Ons popular Mold Max® line of high performance tin-cure silicone rubbers. Mold Max 25 is mixed 100A:5B by weight and cures overnight to a Shore 25A.

Whats Different About Mold Max® 25?

Compared to the other Mold Max® products, Mold Max® 25 has a lower viscosity Part A, making the rubber easier to mix and easier to vacuum de-gas.

The working time for the Mold Max® 25 is an extra-long 60 minutes for large mold pours or multiple mold pour projects.

Because it is a Mold Max® silicone, molds made with the new 25A have high tear strength and a long library life. They are suitable for casting urethane, epoxy or polyester resins, wax, gypsum and other materials.

Mold Max® 25 was used recently to make a replacement wheel for equipment that is no longer in production. In this step-by-step photo gallery, a 2-part rubber mold is made to duplicate an industrial wheel.

TASK® 14 black impact resistant plastic is poured into the Mold Max® 25mold (no release agent required) to create a high performance duplicate.

Materials Used in this Tutorial

Step 1: Preparing Model (Constructing a Mold Box)