Smooth-On URE-FIL™ fillers disperse easily in Smooth-On materials. They can be added to materials in different proportions to achieve a variety of working properties and effects. Some fillers are designed for cost-savings, others are designed for specific casting effects or improved physical properties. Other URE-FIL™ fillers are designed specifically for thickening materials for brush-on or trowelable application.

URE-FIL™ 9 - fumed-silica based thickening agent primarily used with liquid urethane and silicone rubbers for brushon moldmaking applications. URE-FIL™ 9 is added in small amounts to the mixed rubber until the desired viscosity is achieved. URE-FIL™ 9 can also be added to liquid urethane resins to create casting effects and to thicken the material for trowelable casting applications.