The amount of time taken to weld a pipe depends on factors such as the size of the pipe, the working conditions and the welder’s level of skill. In addition, the amount of passes required can change for different jobs and the different welding techniques have different rates of deposition (MIG is generally faster than TIG, for example). However, as a rule of thumb, the average welder can complete 140 inches of weld per hour. By checking this hourly speed against the diameter of the pipe, you can get an idea of how long a pipe will take to weld.