<p>The purpose of exploring the friction stir welding process is to find a suitable application for the joining of traditionally un-weldable materials. Aluminum alloy 7075 and 2024 were the materials used for experimentation as it is a common alloy used in the aerospace industry that cannot be welded via traditional methods. Friction stir welding of a lap joint is a process that involves overlapping two rectangular samples and applying friction to the joint ultimately joining them using solid state joining. Multiple parameters were tested throughout the experiments, those being rotation speed, feed rate, tool depth, and number of passes. Once the plates were welded together, tension tests were performed to determine the strength of the weld. The expected results of the experiments were that the materials would fuse together forming a solid bond between the two metal plates. With increased spindle speed, the welds became stronger; however, this was only the case for 850 and 1700&#xa0;rpm. Once the 3400&#xa0;rpm samples were tested, the force required to sever the weld dropped dramatically. Furthermore, the increased feed rate of the machine appeared to weaken the weld on all the samples.</p>