Abstract: A method for joining together tubular plastic products (1, 2) by heating the joint faces of the plastic products (1, 2) which have been chamfered at least partly in advance, and by passing molten plastic material into the space (4), that is formed between the opposite joint faces. The fixing of the tubular plastic products (1, 2) and the feed of the molten plastic material take place with the aid of a mold tool (5) which is applied onto the space (4), and molten plastic material is passed rapidly into the hollow space between the mold tool, (5) and the joint faces through a feed stub (6) provided in the mold tube.