There are certain adhesives that you can use to stick together two steel pipes which enable you to avoid costly and possibly dangerous welding procedures. These include Polyurethane, Epoxies, and Cyanoacrylate based adhesives. You are guaranteed a satisfying, long-lasting effect using all the above-stated adhesives; however, Epoxy adhesives are infamous for their most prolonged and powerful effect on metal surfaces. Besides, these adhesives are the most wear and weather resistant.