The Double Sided Arc Welding (DSAW) process developed at the University of Kentucky provides many advantages over both conventional arc welding and laser arc welding processes. A nonlinear model was chosen to represent the dynamics of the DSAW method based on experimental analysis of the procedure. Due to the highly dynamic nature of the DSAW process, the model parameters determined via least squares method from a series of experiments were varied. It was determined that the parameters of the nonlinear model were uncertain, but bounded in a given interval. To determine the intervals, a number of experiments were carried out using the same operating parameters. Each experiment provided a set of model parameters, and the interval ranges were determined by the minimum and maximum calculated values for each parameter over the set of experiments. A series of closed-loop control experiments were run to verify the validity and robustness of the interval model control.