B29C 65/3496

Joining {or sealing} of preformed parts {, e.g. welding of plastics materials}; Apparatus therefor by heating, with or without pressure using heated elements which remain in the joint, e.g. "verlorenes Schweisselement" {characterised by the composition of the heated elements which remain in the joint being non-metallic with a coating, e.g. a metallic or a carbon coating}