Radiator tubing formed from brass strip, with wall thicknesses from 0.09-0.120 mm (0.0035-0.0047 in.), has been successfully welded at high welding speed using a CO sub 2 laser. A fully penetrated weld was obtained using welding speeds of > 100 m/min (5.47 ft/s) in production like conditions. The laser used for the welding was a 1700 W, Co sub 2 laser with linear polarisation. A tube with a specially designed "Y" joint was formed in a converted lock seam tube machine. There are several advantages to this new type of "Y" joint, such as higher production rate and the possibility of reducing the thickness of the brass strip by 20-30% when compared to material used in high frequency welding. A large number of parameters were studied including the effects of laser power, welding speed, joint geometry and direction of the laser beam polarisation. Two radiators have been made with solder coated, laser welded tubes. These are currently undergoing mechanical testing. Preliminary results of the testing are favourable.