Radiator tubing formed from brass strip, with wall thicknesses from 0.09-0.12 mm, 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 in production-like conditions. The laser used for welding was a 1700 W, CO sub 2 laser with linear polarisation. A tube with a specially designed "Y" joint was formed in a modified lock-seam tube machine. There are several advantages to this new type of "Y" joint, such as higher production rate and the possibility to reduce the thickness of the brass strip by 20-30% when compared with 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 testing are favourable.