Stick welding vs. wire feed for a tight repair job...

I had to patch a crack in a 1-inch steel tank last Friday. I was set on using 7018 rod, but my partner swore a .035 wire with flux core would save time. I went with the rod, took about 2 hours with preheat and post-weld cooling... it held fine on the air test. My buddy said his way would have been done in 45 minutes though. What do you all lean toward for small pressure vessel fixes?

3 comments

3 Comments

the_dylan29d ago

You said "air test" and that makes me wonder - did you hydrotest it too or just air? For a 1 inch tank wall I'd be nervous about just air unless you were running real low pressure. Also, how big was the crack? If its more than a few inches long 7018 is probably the right call even if it takes longer. Wire feed can be fast but I've seen too many pinholes in flux core on thick wall stuff to trust it for pressure. What kind of prep work did you do on the crack ends?

daniel85729d ago

And honestly on the prep, I think that's the part people rush the most. If you don't drill the crack ends and grind out a clean V, it doesn't matter what rod you pick, it'll just open back up under pressure. I've seen guys skip that step on a compressor tank and the whole repair failed in six months.

hill.andrew29d ago

Had a buddy try to rush a pressure vessel repair with flux core on a compressor tank once. He skipped the preheat on the thick section and ran the wire hot to get it done quick. Thing held for the air test but when he put it back in service the weld popped a pinhole right along the toe after about two weeks. Had to drain it, grind everything out, and redo the whole job with 7018 anyway. Took him a full Saturday that time plus he had to explain to the shop owner why a five minute job turned into a disaster. Seen enough of those little failures to stick with rod on anything that will hold pressure.