What if in welding the polarity of the job and electrode is interchanged??
If you are doing AC TIG welding of aluminum, you can really understand what happens by changing the polarity. Controlling the cleaning/penetration with the AC will really help you visualize it and feel how it works. So, here is how it goes: Electricity flows from positive to negative to create the arc. It is essentially a short circuit. Changing the polarity changes where the heat is focused and how the electrode burns. With the electrode positive or reserve polarity, the current starts from the workpiece and goes to the electrode which causes more heat to build up in the workpiece. You get deeper penetration and a “hotter” weld. With electrode negative or straight polarity, you get less penetration and more filler metal because the heat is concentrated at the electrode. This is the general way it works and if you do SMAW, the rods are specifically designed to work a certain way based on their chemical composition. Now comes to AC. The old machines were basically fancy sine wave genera
