The invention relates to a method of welding a laminate for the production of flexible tubular plastic bodies, which method comprises the following operations: a laminate is shaped around a welding rod; the ends of the laminate to be welded are heated; said ends are pressed together and at least partly cooled; the welded zone is deformed so as to increase its area; and the welded zone is cooled. The invention also relates to a device suitable for using the aforementioned method.