The difference between MIG and TIG welding lies in the way arc is used in both processes. In TIG welding process, a long rod is used to fuse the two metals directly and welds together, and MIG welding uses feed wire that moves through the gun to create the spark and in results, melts to weld the metals.
TIG welders are mostly used for comparatively small projects which needs more precise results on thinner metals. MIG welders are easy to control and use even for beginners and better for longer projects.