Image Number 2 for United States Patent #3957410.
Reinforced plastic pipe and similar tubular members are formed by centrifugally casting filamentary strand materials, such as glass roving, in a rotating cylindrical mold. A solvent dispersed mold release agent may be sprayed into the mold prior to the application of the filament. Thereafter, a spray of catalyzed binder resin is added to the filamentary material. A lance is extended into the mold and contains feeding tubes for depositing the filamentary strand, as well as nozzles for depositing the resin on the surface of the mold. Also, the lance contains extra nozzles for the addition of particulate matter such as sand to achieve desired structural quality and economic fabrication of the tubular member. The amount of the components added and the timing of the component addition is determined by the desired end product to be achieved.