Abstract: In an induction welding process for metal tubing, an impeder having a fiberglass sleeve and an exposed ferrite core is used to concentrate the flow of current along a seam to be welded. The sleeve at its upstream end is connected to a brass fitting which couples a source of coolant to the impeder. The sleeve is loosely connected to the ferrite core by a pin and the ferrite core is exposed and protrudes from the downstream end of the sleeve, thereby allowing the ferrite core to be placed in close proximity to the welding point of the metal tubing. As coolant flows over the exposed end of the ferrite core, it both cools and cleans the exposed end of the ferrite core.