Welding Distortion is a complicated subject.
But one thing is certain…
understanding that weld metal shrinks as it cools is fundamental to understanding ways to prevent distortion.
this video addresses welding stainless steel square tubing and shows a technique for using weld sequence and direction of travel to keep things straight.
Speed tacking involves setting amperage to 30-50 percent higher than normal welding amperage. Then using a torch switch or foot pedal, use very quick blasts of half a second or less to fusion tack weld.
this makes for very quick tack welding that is clean and free from oxidation.
Aluminum Chill blocks are handy for pulling heat out of sheet metal parts. So worth the effort.