TWI Frequently asked questions
by Chris Brown
In speed welding, the filler rod is fed into the joint via a specially designed nozzle. Constant pressure is applied to the rod using the toe of the nozzle, which also introduces hot air to both the rod and the joint.
In hand welding, sometimes known as 'round nozzle welding', the filler rod is fed into the joint by hand to produce the welding pressure. The joint and rod are heated by moving the nozzle in a pendulum motion up and down the rod and along the joint, typically at a distance of 5 to 10mm.
Further information
What is hot gas welding of thermoplastics? How important is the temperature of the welding torch when hot gas welding thermoplastics? What training is available for hot gas welding of thermoplastics? Does it matter what type of welding rod is used when hot gas welding plastics?
