Achieve perfect flow every time with the FLEX-MOLD #4 Ford Cup, a simple, reliable tool for checking the viscosity of gelcoat and marine paint.How it works: Fill the cup and let the material flow through the standardized hole. A drain time of 40-45 seconds indicates ideal viscosity.Too fast (<40 sec): Material is too thin—add more gelcoat or paint base.Too slow (>45 sec): Material is too thick—add reducer gradually and re-test.Why it matters: Proper viscosity ensures smooth, even coverage with no runs, sag, or orange peel. Commonly used with our Rubber product for repairing damaged non-skid areas.Small tool, big results—measure, adjust, and achieve professional-quality finishes every time.