Found out yesterday that a 3/8 weld bead shrinks by almost a quarter inch over 10 feet of steel

I was reading an old trade manual my mentor left me and that stat blew my mind lol. Has anyone else ever measured how much your welds actually pull the metal in on a long run?

3 comments

3 Comments

nguyen.tara16d ago

Bet you see it the worst on handrail jobs or long gate runs. Ive had a 12 foot piece of flat bar pull itself into a smiley face after I ran a bead down it, had to stop and tack every 6 inches to keep it straight. Preheating the whole piece helps a little but your mileage may vary depending on the thickness and how hot you run. One trick I picked up is to skip around instead of running one continuous bead, lets the metal cool and settle more evenly. Clamping it down tight to a heavy table or putting some opposing tacks on the backside can also fight the shrinkage, but you gotta plan for that quarter inch pull before you even strike an arc.

perry.evan15d ago

@the_tessa that spiral trick is actually a physics thing called residual stress release, it's legit used in sculpture.

the_tessa15d ago

Does it ever warp in a way that looks almost intentional? Lol I had a gate frame once that twisted into this weird spiral after I welded it, and my buddy said it looked like modern art.