butt welding video, is the process correct or incorrect?

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I was viewing this video on Youtube and what the guy said seemed reasonable.     However down in the comments section someone said this."Holding the tip to work length may work but it is completely wrong for the MIG welding process. The proper way would to be to lower your voltage or slightly decrease your wire speed. Improper tip to work length simply creates improper shielding and porosity and you are burning the metal."I understand there is more than one way to achieve something but which method will leave you with a good quality weld?Another person said that when spot welding with a mig, you should keep the gun tip over the weld and wait until the orange glow subsides before moving the gun.  He said the residual gas coming out of the tip will help you avoid contamination and porosity.   Everyone I see spot welding is moving long before the orange glow fades.  Any truth to this?Thanks for any advice.
Reply:Alright, so I won't totally rip this guy a new one. He's actually giving some half-decent advise. That being said, these little machines don't have pre/post gas flow options. Holding the gun there isn't going to help. If it was tig welding I'd say definitely hold it there to keep the oxidation away. Thin sheet metal like that is never easy to weld. I would recommend using a copper spoon on the back side to aid in heat transfer from the sheet.  Using .023 wire helps a lot, but even then it's challenging. Optimal gun angle is as close to 90* as possible. The more angle you get, the more mixing of air you'll draw into the weld. The further away you get, the greater your chances for incomplete shielding gas coverage. Sent from my dumb smartphoneTeach Ag Mech - Mike At Home:Lincoln Electric AC225Miller Challenger 172Gas AxeWork:eclectic bunch of 90's vintage blue boxes
Reply:Originally Posted by teachagmechAlright, so I won't totally rip this guy a new one. He's actually giving some half-decent advise. That being said, these little machines don't have pre/post gas flow options. Holding the gun there isn't going to help. If it was tig welding I'd say definitely hold it there to keep the oxidation away. Thin sheet metal like that is never easy to weld. I would recommend using a copper spoon on the back side to aid in heat transfer from the sheet.  Using .023 wire helps a lot, but even then it's challenging. Optimal gun angle is as close to 90* as possible. The more angle you get, the more mixing of air you'll draw into the weld. The further away you get, the greater your chances for incomplete shielding gas coverage. Sent from my dumb smartphone
Reply:Originally Posted by fwillthere is so much to learn about these different welding processes...and it seems it never ends.
Reply:tip to work or "stickout" being excessively long CAN lead to porosity. it WILL lead to inconsistent arc length. too much wire being resistive heated by a long stickout can lead to more being pinched off, which increases arc length, which will just drive you nuts. you'll be playing with the wire speed trying to make it run smooth, but it just wont. trust me, im a terrible wire-feed guy and know every single way to screw it up. that being said, shielding on mild steel isn't that big a deal indoors with a good flowrate and good diffuser/ nozzle.the stuff about holding over tacks until relatively cool is great practice, but not necessary on mild steel, especially when, as stated above, the machine being used likely wont have any post-flow.bosses stuff:trailblazer 325maxstar 200my stuff:sa 200fronius transpocket 180100 amp Lincoln w/f97 f350 DITKevin
Reply:The length of stickout can be varied, within reason, with no ill-effects.I would advise that you get great at doing it "by the book" before seeing how far within reason actually is.Kind of like playing golf:Learn to drive the ball straight before trying to put draw or fade on it.Hobart Beta-Mig 2511972 Miller AEAD-200LEMiller 250 TwinNorthern Ind. Hybrid 200Longevity Stick 140Longevity Migweld 200SThermal Arc Pak 3XR