Rig welds failing on a high pressure drum taught me to prep better

Last Thursday I was working a shutdown at a refinery in Baton Rouge and one of my rig welds on a steam drum started cracking under hydro test. I always thought my prep was good enough, but the foreman walked over and showed me how I missed a tiny bit of mill scale near the root. He swore by using a needle scaler on every inch before even striking an arc, not just a grinder and wire brush. I tried his way on the next joint and the weld laid in perfect, no porosity at all. Now I spend an extra 10 minutes on prep for any pressure vessel work because that one fix saved me a re-do that would have cost 4 hours. Any of you guys swear by needle scalers for root prep or is it just me?

2 comments

2 Comments

amy_martin7d ago

Read an old welder's guide that said mill scale is the devil in disguise.

emma967d ago

Did you ever feel like you were overthinking it with the extra prep time? I used to be the same way, thought a quick grind and wire brush was plenty. But I had a similar thing happen on a gas line a few years back, a tiny speck of rust I missed caused a pinhole leak that was a nightmare to fix. Now I take my time on prep too, it just feels wrong to skip it after seeing what can happen.