Abstract: A method of providing a shed (2) for a high-voltage insulator (1) includes providing a substantially tubular substrate (3), providing an extruder (10) having an extruder head (11) defining an extrusion direction (A), using the extruder (10) to extrude the shed (2) and applying the shed (2) on the substrate (3) while rotating the substrate relative to the extruder head (11). The extrusion direction (A) substantially coincides with the longitudinal axis of the substrate (3), and the substrate (3) is fed through the extruder head (11).

Abstract: A method of providing a shed (2) for a high-voltage insulator (1) comprises the steps of providing a substantially tubular substrate (3), providing an extruder (10) having an extruder head (11) defining an extrusion direction (A), using the extruder (10) to extrude the shed (2) and applying the shed (2) on the substrate (3) while rotating the substrate relative to the extruder head (11). According to the invention, the extrusion direction (A) substantially coincides with the longitudinal axis of the substrate (3), and the substrate (3) is fed through the extruder head (11).

Abstract: A composite article is formed from yarn, comprising high strength fibres and fusible blocking material, and outer fusible material. The yarn is formed into its required shape and placed in a mould. The outer fusible material is introduced into the mould and its temperature is raised so as to melt the lower-melt temperature blocking fibres of the yarn. Under the action of temperature and pressure in the mould, the blocking material fuses so as to fill any interstices between the strength fibres, and the yarn is enclosed within the outer fusible material. The method is useful for forming electrical insulators of high strength glass fibre in the form of a loop (4) blocked against flow of moisture by polypropylene and enclosed within non-tracking polyethylene electrically insulating material (6).