two thermoplastic tubes are welded together in a process which includes severing the tubes by a severing wafer having a temperature of about 350 ° f . to create two cut sections . the severing wafer is removed from the space between the tubes and a hot wafer having a temperature of 500 °- 1200 ° f . is inserted in the space to radiantly heat the tube ends so that they are welded when pressed - together while in an unflattened and open condition .