JoPo Grips

JoPo Mold Sleeve — Precision Custom Thumb Molding Made Easier

The JoPo Mold Sleeve is a purpose-built pro shop tool designed to make creating accurate, professional-quality custom thumb molds cleaner, easier, and more consistent. Designed specifically to fit around an already drilled JoPo thumb, the Mold Sleeve allows pro shop operators to complete the custom molding process outside of the bowling ball.

This outside-the-ball molding process is one of the biggest advantages of the JoPo Mold Sleeve. Traditional in-ball molding can create problems when molding material leaks or flows where it shouldn’t—particularly between the JoPo thumb and the outer sleeve installed inside the bowling ball. Once material gets into these areas, cleanup can become difficult and may interfere with the proper fit and operation of the interchangeable thumb system.

By allowing the mold to be created completely outside the bowling ball, the JoPo Mold Sleeve helps prevent most of these common issues. The sleeve creates a controlled molding chamber around the drilled JoPo thumb, helping provide minimal to no leakage while keeping excess molding material away from the outer sleeve and the interior of the bowling ball.

The Mold Sleeve’s precise fit also gives the pro shop operator better visibility, access, and control throughout the molding process. Instead of trying to contain material while working inside the ball, the operator can concentrate on creating the proper thumb shape, feel, and fit.