Abstract: Tubular components for use in modular fencing systems are manufactured utilizing die-forming of a flat plastic sheet, rather than by profile extrusion of a tubular form. This approach is made feasible by an aesthetically acceptable and structurally sound longitudinal edge joint configuration. The joint is formed by cooperating clip members formed along opposing longitudinal edges of the sheet. The clip members are interlocked with each other in overlapping relation following the die-forming operations. The clip members are substantially concealed by peripheral side portions of the component that are held in closely spaced or abutted relation. Structural integrity is assured by staking overlapping portions of the clip members to each other at longitudinally spaced locations. This can be accomplished with a thin circular blade having teeth that rotate to pass between the peripheral side portions and to press against and deform the overlapping portions, one into the other.

Abstract: A plastic siding panel which includes an upper connector, a medial main portion, and a lower connector. The connectors are complementary in shape so that they interlock with other siding panels of like construction. At least one of the connectors include a strip of high strength material for rigidifying the siding panel. The siding panels are fabricated by extruding a monolithic, substantially planar sheet composed of three different materials. Two of the materials are formed as layers which extend over the entire sheet. The third material is a high strength material adapted to rigidify the siding panel. After extrusion, the sheet is formed into a siding panel having a main portion, an upper connection and a lower connection.