mig and fluxcore on PIPE

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]just want to see what tips i could get from you guy....i can weld tig and stick but ive never welded mig or fluxcore. here are a couple of questions to start off.1. is mig for the root only? or is it used as a filler and cap also.2. what about fluxcore.... filler and cap only or is it used for root also?i have a lot more questions but ill start off with those 2
Reply:Hi GTO,1 - No, Mig is not just for the root pass.  Short circuit mig can be used to weld the fill and cap passes.  So can pulsed-spray arc mig.  Pipe welding with GMAW can be performed with solid wire, gas-shielded fluxcore, self-shielded fluxcore, and metal-core filler metals.2 - No, fluxcore is not normally used for the root pass in my experience.  It can be used, but typically there would be some slag or residue on the root side of the joint that would need to be cleaned up.  Pipe used in Structural applications, where root cleanliness and excess reinforcement are not so critical, can and is done with fluxcore for the root, fill, and cap passes.Next questions?Benson's Mobile Welding - Dayton, OH metro area - AWS Certified Welding Inspector
Reply:As a Pipefitter the above answer is correct. Done lots of pipe joints in the shop with hard wire.Brett B & B Fabrication and Welding Inc.Spalding, MI.
Reply:is mig downhill only or can it be welded uphill as well ?is short arc more like fluxcore or more like mig ?
Reply:GMAW can be performed uphill or downhill on pipe in any position.  The correct filler metal and powersupply settings are needed; and they differ greatly from one filler metal and technique combination, to another.Short arc is short circuit GMAW or MIG.  I'll answer your second question by defining some terms, since I suspect there's some confusion on your part.  I don't know what your welding experience level is, so if I'm mistaken and preaching to the choir, please accept my apologies.MIG is the slang for any welding process that uses a gun and a continuous wire feed.  The AWS approved abbreviation is GMAW[Gas Metal Arc Welding]GMAW can be broken down into a whole bunch of sub-categories; or at least I tend to think of it in these terms:Transfer modesShort circuit - low voltage, low wire feed speed (WFS).  Spatter with (relatively)low penetration.  All position welding process.Globular - low voltage, higher WFS.  Lots of spatter. Lots of heat.  Flat or horizontal onlySpray arc - high voltage very high WFS. No spatter, no smoke, lots of heat.  Usually flat or horizontal positions.  (Limited filler metals can be run in Spray arc, out of position.  But the bulk of them are limited to flat or horizontal positions.)Pulsed Spray Arc. - everything the same as spray arc, but all position welding and lower average heat input to weld.Do a google search on these terms and you should be able to find some videos or drawings that illustrate how each process works and how they are different from each other.Filler metal typessolid wire -  always uses shielding gas, useful with all transfer modes.Flux core wire - may or may not use shielding gas.  Used with all transfer modes.Metal core wire - always uses shielding gas, commonly used with spray arc.How all these choices fit together would make up a long novel, so I'll cut it off here.  What else would you like to know?-Dave Originally Posted by gto_welder01is mig downhill only or can it be welded uphill as well ?is short arc more like fluxcore or more like mig ?
Reply:Originally Posted by gto_welder01is mig downhill only or can it be welded uphill as well ?is short arc more like fluxcore or more like mig ?
Reply:Originally Posted by SandyLesson #2, sections 2.4 and 2.5http://www.esabna.com/EUWeb/AWTC/Lesson2_1.htm