My brother bought a cheap Chinese MIG welder for a quick job & then stripped and rebuilt it to proper safety & wiring standards, including getting L & N around the right way. Fortunately, he's time served and spent 35 years running electrical plant maintenance.
He even threw the supplied gasless welding wire out as it was EN1APb type material so just fizzed when passing current.
BigClive.com on youtube is a regular critic of Chinese electrics (he's qualified, too) & good entertainment.