Abstract: A method and article for joining two substrates or repairing a substrate comprising positioning in thermal contact with and surrounding the substrate(s) a tubular article comprising conductive polymeric material. Two electrodes extending along the whole or part of the article as connected to a source of electrical power to cause current to pass through and heat the article. The conductive polymeric material is urged radially inwards towards the substrate(s). The radially inward movement may be caused by recovery of the conductive polymeric material, or by the use of elastomeric material.