MIG vs Stick on thick boiler tube - which one actually holds up better over time?

I've been running stick on girth welds for years and swear by the penetration, but my new guy swears MIG is faster and just as strong with the right wire. Last month we had a 1/2" tube joint fail on a 10 year old MIG job and I'm wondering if anyone else has seen that kind of thing happen.

3 comments

3 Comments

williamhill1mo ago

Thick boiler tube and MIG, that's like me trying to use a butter knife on a ribeye steak - technically possible but you're gonna have a bad time. Ten year old joint failing on MIG tells me more about the wire choice and gas coverage than the process itself though. Stick's slag system gives it that forgiving nature for dirty or thick stuff, while MIG needs everything clean and perfect to match it. Bet that old failure was porosity or lack of fusion from a windy day or cheap gas. Had my own share of MIG birds nests on heavy wall that made me question my life choices, so I stick to 7018 on anything over 3/8 inch now.

james_singh71mo ago

Used to swear by MIG on everything. Your point about slag forgiveness on dirty thick stuff makes a lot of sense now. Might have to give 7018 another shot on heavy wall.

kelly.nora12d ago

I mean, is it really the process's fault if the joint was set up wrong? Sounds like the real issue was somebody skimping on prep or running shitty wire. I've had MIG hold up just fine on heavy wall boiler stuff when I bothered to clean the mill scale off first and kept a sharp eye on gas flow. Stick's great for forgiving dirty metal but it's not like 7018 is magic either - you still gotta keep it dry or you're gonna get hydrogen cracking anyway.