Pipe welding w/ 100% CO2

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Working on welding 8" sch 40 pipe with 100% CO2 .035 solid wire. Pipe is in 5g, welding is downhill. My only issue is going from vert down to overhead.  Problem is that the welds sag down and it drips off alot, probably creating some inclusions.Do I just need to change my angle so im running very close to perpendicular to the pipe and run it faster, or should I set up the machine so it welds real nice overhead and just account for that while on the flat and vert portions of the pipe?Ill grab some pics after another go tomm.Have we all gone mad?
Reply:Give more details about your voltage and WFS.  Generally speaking, if you're using a weave technique, you need to spend less time in the center of the groove, and more time pausing on each side.Less drag angle, transitioning to perpendicular to the pipe as you reach the 6oclock position should help a bit.There's (usually) no rule against adjusting your settings as you change positions on the pipe.  You should be able to turn your voltage and WFS down a bit while you're welding from 4 oclock to 8 oclock on the pipe.  A little less heat on the bottom of the pipe will make it easier to control the puddle.8" sch 40 is pretty thin stuff.  How long are the pipe sections you're welding?  You might benefit from a brief pause to allow the pipe to cool down before welding on the bottom...This depends on how big a hurry you're in, and what sort of interpass temp limitations you're operating with.Benson's Mobile Welding - Dayton, OH metro area - AWS Certified Welding Inspector
Reply:Running about 180-220 on the WFS depending on the pass, 19.5-22 volts to match.Im not welding this for a job, this is for one of the classes im in right now.  No parameters are set, this is just for practice.Im trying to weld half the pipe in one start/stop, is it acceptable to work just from 4-8 and then 12-8 12-4?I did weave the cap pass which worked pretty well, even on the overhead.  I was running that at the lowest of all the passes around 180 IPM and 19.8 volts  Biggest problem wasnt with the weave but with the fill stringers once was working around 5-8, it all went to hell.  I setup a plate overhead and set the machine up for that and it ran pretty well, so I guess its just not being able to get in a good position.Have we all gone mad?
Reply:What's the brand of wire you're working with?  Not knowing that, it sounds like you're voltage and WFS are in the right ballpark.Welding half an 8" pipe joint in a single pass is most efficient, but not a requirement insofar as I know.  I generally weld from 12 to 4, reposition, and weld 4 to 6.  Then reposition and weld 12 down to 8, reposition, and finish the weld from 8 to 6.Since you're practicing, quench the joint in water or wait a few minutes before welding the cap and let the weld cool down some.  Once you get the hang of welding the bottom of the pipe, stop using the water quench or shorten your delay before capping the joint.  Don't do this in the field, only for practice.  I assume you're running a root pass, a single fill/hot pass, and then a cap.  The fill and cap should be run as a weave, on the pipe you're working with. Running the fill as a stringer on the bottom of the pipe likely the source of your problem.  Try weaving the fill pass and filling the joint until you're within 1/16" - 1/8" of flush.  Then cap the weld with a weave bead.Benson's Mobile Welding - Dayton, OH metro area - AWS Certified Welding Inspector
Reply:Wire is esab, I dont know exactly what.Im running 1/16 open root pass, hotpass, 2stringer layer and 3 stringer layer for fill and weave cap, my problem was compounded on all of the fill passes.  Ill try to weave in the last fill layer, that does sound like a better idea.I did quench in between all the layers, still was having an issue.  Im just gonna set up again tomm and see what I can do.Have we all gone mad?
Reply:I find .045 wire keeps  a steadier arc with the C02.  150-165 or so ipm, 18 to 19 volts.  I could not do the whole job on one setting.DavidReal world weldin.  When I grow up I want to be a tig weldor.
Reply:You did say 8" schedule 40, right?  According to my references, the wall thickness on this stuff is only 0.322".  How are you cramming 8 beads in 5 layers on pipe this thin?Should be 3 beads in 3 layers if you're bevel angles are ~30°, included angle 60°...What's the wall thickness of the pipe you're using? Originally Posted by sn0border88Wire is esab, I dont know exactly what.Im running 1/16 open root pass, hotpass, 2stringer layer and 3 stringer layer for fill and weave cap, my problem was compounded on all of the fill passes.  Ill try to weave in the last fill layer, that does sound like a better idea.I did quench in between all the layers, still was having an issue.  Im just gonna set up again tomm and see what I can do.
Reply:Hmmm... i guess its not 40 then, im new to pipe most of my experience is with tube.  It is around 7/16 thick IIRC.I did another today, it was mostly a problem with my gun angle and speed.   Im still working from 12-6 but im getting used to how I have to contort as I come around the bottom.  This one came out real nice, thanks for the advice.My camera has gone missing so you'll have to settle for a bad phone picture. Attached ImagesHave we all gone mad?
Reply:Here's a good reference for pipe dimensions and what the common terminology meanshttp://www.engineeringtoolbox.com/st...ions-d_43.html7/16 wall thickness isn't a standard dimension; but it's close to schedule 80 for 8" diameter pipe.That said, I see where you could accomodate some more beads.  But, unless your boss/instructor says otherwise, try this....Root, small weave for hot pass, Weave Fill, Weave Cap.  That fill pass should be just below flush on the pipe.The photo you posted looks pretty good.  Keep at it and you'll be doing it in your sleep...Benson's Mobile Welding - Dayton, OH metro area - AWS Certified Welding Inspector