Abstract: A thickener apparatus includes a shaftless cylinder mold having a perforated cylindrical shell supported by two end members one of which is an open frame structure having radially extending support beams interconnecting a short rotational shaft aligned with the axial center of rotation of the cylinder, and a peripheral ring member which supports the shell of the cylinder mold. The shell is sufficiently rigid to be self supporting and has a backing cloth overly covering the perforated portion of the cylinder, and a face cloth covering the backing cloth, both of which act as a screen to permit the white water to collect in the central hollow portion of the cylinder mold to be subsequently discharged therefrom.