Abstract: An improved conveyer apparatus for processing and degassing a mixture of materials for forming solid surface end products, such as cultured marble and other polymer casting products. The conveyer includes a conveyer housing with an internal passageway having a conically shaped upstream section and a downstream section. A rotatable screw is located in the internal passageway and has a shape that corresponds to the shape of the internal passageway, so that an upstream section of the screw is conically shaped. The upstream section of the passageway has an inlet that connects to a source of materials, such as a mixer, and the downstream section has an outlet that permits the mixture of materials to exit the conveyer apparatus. A vacuum source is connected to the conveyer housing to remove gases from the mixture as it is being conveyed through the conveyer.