a method of manufacturing a molded article from a settable mixture includes the steps of in - taking a plurality of components into a plurality of separate material discharge containers sized relative to each other to provide the required mix ratio of the settable mixture . the components contained in the material discharge containers are discharged to a mold tool through a mixing head that receives each of the components separately and thoroughly mixes them into the settable mixture . the settable mixture flows from the mixing head to fill the mold tool . the mold tool rotates about an axis during the filling step to evacuate air from the mold tool . pressure of the settable mixture is monitored during the filling step and rate of discharge of the settable component is varied in response to changes in pressure of the settable mixture .