This article investigates a defect problem related to laser welding of tailored aluminum blanks. During the initial few millimeters of welding the weld was intermittent. By applying an analytical line source model the weld was shown to experience overheating close to the starting edge. This overheating was reduced by ramping the power during the initial 100 mm and this made the defects disappear. (C) 2000 Laser Institute of America. [S1042-346X(00)00301-6].