A method of mixing silicone rubber polymers with fillers and/or other additives without employing a kneading type action wherein the ingredients to be mixed are impacted with a high speed mixing blade for a first period of time in which the blade is operated at a tip speed of about 150 feet per second, until the ingredients are reduced to relatively small uniform particles and then operating the mixer blades at a speed of about 300 feet per second until sufficient viscosity of the material is reached.