Abstract: The weld formation and porosity characteristics of 2014-T6 aluminum alloy using three different cold metal transfer welding processes were investigated. Experimental results show that, with constant wire feed speed of 7.5 m/min, contact tip to work distance of 15 mm and pure argon shielding gas flow rate of 25 L/min, finger-shape penetration is observed using the conventional CMT process and there are many gas pores in the lower and upper part of the weld. The volume of the finger-shape weld metal is decreased and the gas pore is reduced significantly using the pulsed CMT process. The porosity is almost eliminated using the welding speed of 0.6 m/min. Spherical-shape weld is achieved using the CMT welding process. The gas pore is also significantly reduced and drop to zero with the welding speed of 0.4 m/min.