Mig smut?

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Just got a new bottle of argon.  Trying to butt weld 1/4" aluminum and pushing on a miller 210 with 3035 spoolgun.  Got black smut along both sides of the weld.  Switched to 1/8" stock and changed settings and still got the smut.  Using 35 wire and 30-35 cfh gas.  Read somewhere that the smut is normal for a spool gun.  Wondering if I can do anything to get rid of it.  Have a bunch of 1/4" 2" angle with drill holes that I want to save and fill the holes.  I make a pass around the hole but of course, when I get back to the start I will hit the smut.  Any suggestions will be appreciated. Attached Images
Reply:It looks like there is some kind of surface contaminate on the metal you are welding. Have you tried wire brushing before you weld?6"XX P5P8 6G
Reply:Ran a stainless cup wire brush and a stainless brush and acetone over it before I tried to weld.  All are dedicated to aluminum.
Reply:From the picture, it looks like a lacquer, or some kind of protective film that was sprayed on the material.  I would try a sanding disk next.... It sounds like your welding process is correct.   just thinkin6"XX P5P8 6G
Reply:I weld al. alot mostly with tig. every now and then for big fillets i break out the pulse arc. never a straight mig. I know with the pulse me and other guys in the shop almost always get the soot when pushing. I just pull it and it goes away. The science behind it i dont know. Wire brush takes care of the soot. the weld looks good though. thats what really mattersWeldandpower 225Heliarc Rig for itTorchesect ect ectLifes Short WELD NAKEDLooking for a SA200
Reply:Some sooting is normal with aluminum mig if the metal is less than very clean.  I get more soot pulling than pushing with mig.  Pushing gives a little better gas coverage ahead of the weld.Try sanding the weld area with a sandpaper flap wheel on an angle grinder before welding it.  Get the edges too not just the flat surface.MM350P/Python/Q300MM175/Q300DialarcHFHTP MIG200PowCon300SMHypertherm380ThermalArc185Purox oaF350CrewCab4x4LoadNGo utilitybedBobcat250XMT304/Optima/SpoolmaticSuitcase12RC/Q300Suitcase8RC/Q400Passport/Q300Smith op