Proper Starts & Stops for Arc Welding

Video Transcript

" Hello! My name is Mac. On behalf of expertvillage.com, I am here to continue our discussions on the theory of arc welding. Previously we had discussed running a stringer bead and the proper direction of travel and how a student makes a proper bead of weld. These electrodes eventually become used up as you proceed with your weld and it becomes often necessary to change the electrode and pickup a bead of weld where you stopped and continue. Now it is extremely important to do this in the proper way. Avoid by all means making excessive strike marks on the plate. Strike marks are defects where cracks can start. The appropriate method for doing this is as follows. Proceed with your simple stringer bead, stop, change the electrode. When you go to strike your arc and reestablish your bead, strike your arc in the area where you will be welding over in the direction of travel, backup, pick up the end of the bead where you stopped, reverse direction and go back over top of your strike marks, continuing your bead of weld, melt the strike marks out and you will not have any strike marks on the plate. Strike marks are a defect and you need to avoid them. When the bead gets down to the end of the plate, make a simple back step of three eighths or quarter of an inch to fill in the crater crack at the end or the crater at the end of the weld so that you don’t get any cracks emanating from it and break the arc."