I was welding a 3/4 inch thick plate on a pressure vessel in a Philly shipyard last month when my arc suddenly went wild and blew a hole right through the seam.

I had to stop, grind out a huge section, preheat the whole area again with my rosebud for 20 minutes, and re-weld it with a slower travel speed, which made me wonder if anyone else has had a sudden arc wander issue with their machine on thick material like that?

3 comments

3 Comments

kevin_wells463mo ago

Nah, I've seen that happen with a bad rod more than a bad ground... moisture in the flux can make the arc go nuts on thick stuff.

wright.finley3mo ago

That's a massive plate to blow through. The arc going wild on 3/4 inch steel is a serious machine or setup problem, not just a bad pass. Did you check your ground connection was still tight and clean? A loose ground can cause that exact kind of crazy arc behavior, especially on a big piece that can act like a giant heat sink.

river_rivera4520d ago

Honestly I see it different than Finley there. A loose ground on that thick of steel would usually give you a weak arc or it'd be sputtering not a sudden wild blowout. I've had grounds that were barely hanging on and it just makes the puddle cold and messy not blow a hole through 3/4 inch. More likely your machine was set too hot for that rod or the angle was off and you got a bad arc blow from the pressure vessel being magnetized. Those big tanks can hold a ton of residual magnetism from the welding itself and it'll yank the arc sideways when you least expect it. You'd feel it fighting you before it actually lets go though so maybe you just got caught off guard by a sudden shift in the magnetic field.