Greets all & good morning. would like to preface this by saying I'm not a full-time weldor. Used to do alot more but now I like to pick and choose my work -- 99% of the time its TIG -- typically Al & SS structural -- not a pipe weldor!
close friend of mine is a contract weldor and asked me to lend a hand running tig root pass on a lot contract (he'd follow up behind with a 7018 cap).
welding 3" sch 80 pipe on a bench. These are elbow assemblies made of 1 elbow, an 8" extension on each end, and 2 flanges. I only needed to weld the elbow/extension.. not the flange.
I didn't need to bring anything except gloves and a helmet -- everything else would be provided.
(They supplied an old scratch-start aircooled torch kit wired to the oldest DC machine I've ever seen -- but thats a different story)
anyway, I found 300 of these assemblies already "preped" and ready to weld. each was spot welded and they used 3/8" rounds (with 3/4" mig beads!) in four places around each joint -- every
90 degrees to set the gap -- which meant I could only weld 'round the joint about 1.5" before I'd have to stop and grind that 3/8 round out and fix the bevel that the mig "tack" filled.man this is getting long winded -- sorry.
bottom line is: is a 3/8" gap pure madness on 3" pipe?
i started welding these flat on the table (1G position) but couldn't get a consistent profile on the inside penetration. (all they had was 3/32" filler and 3/32" tungstens).
Next, I flipped them up on their flanges and welded each joint in a 2G position and I got much more consistent results with a great profile on the inside.
One satisfactory completed piece, with only the root tig weld, on two joints (less than 20" of weld bead) took me exactly 45 mins (including the grind time).
Q: is it my lack of experience with pipe welding? is a 3/8" gap on this size pipe normal? in the end the welds looked good, inside and out -- got a cupwalking ripple pattern even though I had to float it (don't know how to walk) because of the CHASM I had to cross.
there were no prints / specs / etc to follow.. just "here's your pile of stuff -- weld it up for us"
thanks for stick'n through this. :) Tony