Traditionally welding thin aluminum has been a challenge. When part ﬁt-up variations start to come into play (gaps in the joint), it becomes even more challenging. The innovation of AC Pulse with GMAW has helped to improve consistent aluminum welding on material as thin as 1mm. AC Pulse helps to control heat inputs, increase travel speeds, increase deposition rates, as well as help with gap bridging – common with part ﬁt-up issues. This project will look at improving productivity, maintaining high weld quality, and overall process cost reductions that can be gained by using GMAW AC Pulse while welding thin aluminum sections. Welding experiments will compare standard pulse to AC pulse in joints with varying gaps.