With and Without Gas questions...

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More Noob questions:(1) If I were to use un-shielded wire in my MIG welder and not use gas...I'm sure the weld would be no good strengh wise.  But, for practicing, will the welding behavior be the same as if I had gas?  I'm having trouble with all the smoke and splatter.  Wanted to see if it would be better before I get the tank and regulator.(2) Can I use the same gas for both mild steel, chromoly and stainless steel (304, 316 and 316L)?  If so, would it be Argon, Argon/CO or the tri mix Helium/Argon/O???
Reply:If you're getting a lot of smoke and splatter, you might want to check a few things first.  MIG can't stand rust of paint or other contamination on the weld stock.  If you try to weld with un-shielded wire and no gas, you'll get welds that look like swiss cheese and are not much stronger.
Reply:no you can't use bare wire mig without shielding gas. you get extreme oxidation, nasty sputter and a weld that comes out looking like swiss cheese.  It's nothing like welding with gas, and it doesn't work all that great.2. you probably could get a tri/mix to do all 3, but it would be pricey and a waste to run the tri-mix on just mild steel.  alternatively you could get a cylinder of 98-2 which would work for the stainless and chrome- moly and a cylinder of C15 or c25 for the mild steel.  You could use the 98-2 for mild steel but again it would just be more pricey than necessary.I don't recommend tri-mixes unless you absolutely have to, very pricey especially for the home hobbiest or noob beginner.Welding EngineerCertified Scrap Producer
Reply:You'll have alot more smoke and spatter without the gas than with it so eliminating the gas isn't going to help your problem of not seeing the weld.  Also as stated above, the weld will be no good, so no reason to weld without the gas.  The proper gas for short circuit mig on mild steel is argon/co2 mix or straight co2.  Tri-mix is for stainless, pure argon is for aluminum and argon/oxygen is for spray transfer mig of steel and stainless.MM350P/Python/Q300MM175/Q300DialarcHFHTP MIG200PowCon300SMHypertherm380ThermalArc185Purox oaF350CrewCab4x4LoadNGo utilitybedBobcat250XMT304/Optima/SpoolmaticSuitcase12RC/Q300Suitcase8RC/Q400Passport/Q300Smith op
Reply:Read some MIG tutorials for more info, the Miller site has some good vids.Post the model of your MIG so owners may suggest settings.Like all welding, expect to do many hours of practice. Scrap is your friend.Bend and or break test samples. I'd get the cylinder of C25 for mild steel and put in the hours to get proficient.Our MIG students spend a few WEEKS welding 9.5 hrs (actual booth time) per day. You may get good enough for what you want to do with much less time, but the biggest "investment" in welding isn't the equipment or the consumables. Great rewards require great effort.
Reply:Originally Posted by farmallOur MIG students spend a few WEEKS welding 9.5 hrs (actual booth time) per day. You may get good enough for what you want to do with much less time, but the biggest "investment" in welding isn't the equipment or the consumables. Great rewards require great effort.