Had to pick between a 3/8-inch and a 1/2-inch backing bar for a 2-inch thick pressure vessel weld.

The spec called for a 3/8-inch bar, but the old foreman at the Detroit yard always swore by going up to a 1/2-inch for anything over 1.5 inches thick. I went with the 1/2-inch for the root pass on the longitudinal seam, and the heat control was way easier, but now I'm second-guessing if it added too much stress. Has anyone else had to make that call on a thick plate job?

2 comments

2 Comments

sarahsullivan10d ago

Man, I used to be all about following the spec to the letter. Thought those extra rules were just old guys being stubborn. But I saw a weld fail on a test piece once where they skimped on the backing bar, and it had a crack right up the root. Ever since then, if the foreman with thirty years says go thicker, I listen. Your heat control being easier probably means you got better fusion. I'd sleep fine if I were you.

felix_thomas7310d ago

Yeah, heard a guy say specs are the bare minimum, not the goal. Makes you think.