benc53•1mo ago

My uncle told me to skip the pre-heat on a 2-inch plate job and I should have listened

He's been in the trade for forty years and said the extra time was a waste, that the torch would bring it up fast enough. We were working on a pressure vessel in a plant outside of Omaha, and I was set to do it by the book. I spent an hour getting that whole section to 350 degrees before the first pass... only to watch the weld puddle act like it was on ice. Had to stop, let it cool, grind it out, and start over. The foreman came by and just shook his head. My uncle's way would have saved half a day and a lot of rod. Anyone ever run into a situation where the old-school method actually worked better than the procedure?

3 comments

3 Comments

wrenh6519d ago

Bet the rod was wet or the plate had moisture in it.

ray1891mo ago

Man, that's rough. But honestly, I gotta side with the book on this one. Pre-heat on thick material is there to slow the cooling rate and prevent cracking. Your puddle acting weird sounds like maybe the base metal was pulling heat away too fast, which is exactly what pre-heat is supposed to fix. Could've been a different issue with the technique or the rod itself.

kim3731mo ago

Yeah, heard a guy say once that skipping pre-heat is like trying to paint over a wet wall... just asking for trouble.