I am here to continue our discussions on shielded metal arc welding or stick welding as it is commonly known. Up to this point we have covered how to strike an arc, how to run a stringer bead, how to make a proper stop and start and how to fill in the crater at the end of the weld. The next technique that a student needs to learn to do is make overlapping stringer beads. When a student needs to make a big weld, he uses multiple passes of stringer beads overlapping one another in a specific order to create a larger weld to fill in for instance a bevel or a gouged out section of metal. What we do is we run a simple stringer bead on a plate of steel. We chip the slag off of it because you cannot weld over your slag. Slag is composed mainly of oxides and it melts at a higher temperature than the base metal so you can actually weld over a slag and entrap it in the weld puddle. You clean the weld, wire brush it, run another bead as this cross section view here, this is an end view of a number of beads weld on a steel plate, we create one bead of weld, we put another bead of weld right beside it actually overlapping it 50%, we clean it, we put an another bead of weld overlapping it, cover 50%, chip the slag off of it, put another bead of weld over top of it, so on and so on and so on. What I would have my student do is take a steel plate this large, cover it completely with overlapping stringer beads, incorporating proper stops and starts and back steps on the end, fill in the crater and do this. Perhaps cover two or three plates like this, both sides, traveling right to left, left to right away from them and back towards them. It is the practice that will make you a good welder. Follow the proper procedure, you cannot fail.
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