MIG on Alum, what am I doing wrong?

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I put an aluminum kit in my Lincoln 175 this afternoon and hooked up my argon bottle. I wanted to tack some pieces together on the car for a windshield frame I'm making so I wanted to tack the pieces with the MIG. The wire was .035 5052 alloy and the material was 3/8" 6061. I had no idea what settings to use so I used the high settings on the door for .035 wire on steel. The sound was not the bacon frying I'm used to but more of a woosh kind of sound and the wire burned back to the tip and welded itself to the end. I turned the heat down some and I was able to get a few tacks without melting onto the tip but the sound was still a wooshing kind of noise. The welds were really ugly and there was black soot all over the workpiece after each tack. The picture of the end does not show all the black soot because of the flash but the area 3/4" to either side of the tack is black.Do you not get the same sound MIG welding aluminum as you do with steel? At least the pieces are stuck together so I can TIG them.Cut an MGB and widened 11" C4 Corvette suspension and LT1 Chevrolet power & 6 spd. Pictures here:Part 1http://forum.britishv8.org/read.php?13,7581Part 2http://forum.britishv8.org/read.php?13,22422
Reply:Hello Jim, you will not get the same sound as steel, unless you are operating your steel in the spray arc mode of transfer. Argon, as is required for aluminum welding, "should" put you into spray arc mode which will have the whooshing sound you have described. For the machine that you are using it is likely that you will need to use the highest voltage setting that it is capable of and then increase your wire speed so that it doesn't burn back to the tip and instead "pinches off " approximately 1/8" to 3/16" above the weld puddle while holding around 3/8" to 1/2" wire stick-out. Be sure to push your puddle too (whenever possible) as opposed to dragging it. This will help to keep the oxides cleaned out from in front of your weld bead. Did you mean to say that your wire type was 5356 instead of 5052? Also, the 5356 will exhibit more soot after welding than say 4043 and that is somewhat normal. Good luck and best regards, Allanaevald
Reply:I can't recommend highly enough setting up the adjustment on scrap, especially since it is a new experience for you. when I was welding aluminum professionally and knew my machine well I still set adjustments on scrap.Dynasty 200DXPassport plus w/ spoolmate 100victor 315c oxy/(act and prop)Miller digital elitemilwaukee power tools
Reply:Where I work we have to use helium for our shielding gas and it makes a LOT of black smoke on the plate. We get more penetration with helium than with argon so that is why. I never liked using mig for aluminum for the hard time I always have with the look of them.CERTIFICATIONS:7018M- H.V.O10718M- H.V.O11018M- H.V.O9N10- H.V.O71T-1-HYM- H.O.V100S1 PULSE ARC 0,035- H.O.V100S1 PULSE ARC 0.045- H.O.VER70S-3 PULSE ARC 0.035 H.O.VER70S-3 PULSE ARC 0.045 H.O.VER5554- H.O.V
Reply:If you can push any wire through a mig gun, its 5356.   4043 is too soft.  Forehand with the gun, 30 or so cfh pure argon.  Like said above, turn the volts all the way up and adjust the wire speed for a decent weld.  Plate that thick would like preheat.DavidReal world weldin.  When I grow up I want to be a tig weldor.
Reply:Originally Posted by David RIf you can push any wire through a mig gun, its 5356.   4043 is too soft.  Forehand with the gun, 30 or so cfh pure argon.  Like said above, turn the volts all the way up and adjust the wire speed for a decent weld.  Plate that thick would like preheat.David