Common TIG Welding Issues, Hard Starting - Back To Welding Basics | Part 9

Common TIG welding issues. Part 9. TIG: Hard starting.When experiencing starting issues with TIG welders, among the many possible causes, the one that seems to always surprise me and the customer as to it’s transient nature is gas flow. Issues with arc starting and gas flow go hand in hand as too much gas flow or too little gas flow can create arc instability not only during starting but also during welding. For a proper arc to start, the weld zone must have proper shielding. Now of course, that seems obvious, but turbulence caused from too much gas flow can destabilize the arc. Not only that, it can “suck” oxygen due to the venture effect into the weld causing tungsten contamination, pitting, and rapid consumption. Too little flow will do the same, but will appear more consistently than too much flow. Too much flow can cause intermittent issues. Along those lines gas pre-flow time plays into reducing turbulence around the weld zone at arc start. How this works is that due to the back pressure of gas in the line when the solenoid opens to start gas flow, a “burst” of extra gas is discharged through the end of the nozzle. This quick burst can last over a second, depending upon the line length and design of the pressure hose entering the back of the welder. As the hose balloons it stores extra gas that will be relieved when the signal from the switch pops open the solenoid. Setting a little longer preflow time not only gives the gas flow time to settle down, it will also help flood the area with the heavier-than-air argon so that a clean stable arc can be produced. Everlast Power Equipment, your complete TIG welding resource.Learn more on our welding forum