I was welding with my Bessey clamp on my welding table, Solter Cott Inverter arc welder. I was welding some angle iron. I think I had the earth clamped onto the Bessey clamp rather than the table. I'm not sure what happened, the rod might have stuck, but I heard the arc coming from somewhere else and noticed that one corner of the Bessey clamp had welded itself onto the welding table. It was only a small weld and it came off easily, but I'm not sure how it happened. I had the earth clamp on the copper screw.