A bad weld on a boiler in Toledo made me switch up my whole pre-heat routine

We were on a shutdown job at the old power plant there, and I saw a guy try to weld a thick section without enough pre-heat, which caused a nasty crack right down the seam. Now I always use my temp sticks and double-check the metal is hot enough before I even strike an arc. How do you guys make sure your pre-heat is right on thick-wall jobs?

3 comments

3 Comments

riverm481mo agoMost Upvoted

Yeah, my buddy learned that the hard way like willow_martin said about soaking the whole area.

dakota_murphy901mo ago

Man, that's the thing right there. It ain't just about getting the surface hot, you gotta push that heat deep into the metal so it soaks all the way through before you even strike an arc. I've seen guys rush it and end up with that cold lap or a crack right down the middle of the weld bead a week later. That extra five minutes is just cheap insurance compared to grinding out all that mess.

willow_martin1mo ago

Got a little ritual now because of a similar mess. I'll use the temp sticks like you said, but I also keep an old-school surface thermometer in my box as a backup check. Lets me see the exact number instead of just the crayon mark melting. On really thick stuff, I'll even move the heat source around a bit before welding to make sure the whole area is soaked through, not just the spot I'm aiming at. It adds maybe five minutes to the setup, but that's nothing compared to fixing a crack later.