MIG Advice Please

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For a lawn sculpture I’m building, I need to MIG weld some 16 gauge 1 1/2” square tubular steel to a base of 1/4” steel plate.  There is also a small support piece of 16 gauge 1/2” square tubular steel.  (See photo of mockup below.)  I’m unsure about what to set my Hobart 190 machine for.  When I do filet welds on two pieces of 16 gauge steel using 0.030” ER70S, setting V = 2 (about 18 volts) and wire speed to 40 (about 200 ipm) works nicely.  For 1/4” steel, the Hobart guide recommends settings of V = 6 (about 24 volts) and wire speed of 70 (about 300 ipm), but I believe this would just vaporize the 16 gauge steel.  So -- what do you do when you need to join metals of different thicknesses together?  Do I just split the difference in voltage and wirespeed?  Or is there some totally different way to handle this situation?  BTW, I’d also like to say thanks again to everybody who responded to my previous post (“Ugly MIG Welds”) -- my 16 gauge to 16 gauge welds are looking much better now. Attached Images
Reply:Basically use a setting closer to the thinner metal. But torch angle and movement makes the biggest difference.  It needs to be angled into the thick plate then wash the weld puddle up into the thinner plate.Tiger Sales:  AHP Distributor    www.tigersalesco.comAHP200x; AHP 160ST; MM350P,  Spoolmatic 30A; Everlast PowerTig 185; Thermal Dynamics 60i plasma.  For Sale:  Cobra Mig 250 w/ Push-pull gun.  Lincoln Wirematic 250
Reply:Set your welder for the thick plate and just grab the edges of the thinner square tube. Use the thick plate to absorb the heat and every time you make a circle pattern just slightly go into the thinner tubing but don't stay on the thin tube for a long time. That's how I would do it.
Reply:I'd set my machine for the thicker metal and use a technique to "wet" the puddle over onto the thinner metal.Think of trying to oxy/acetylene weld different thicknesses. You would still have to get the thicker metal up to heat.Thanks,HoboLincoln SA200's... at least 15 - 20. They come and go. Growing partial to the "Short Hoods" in my old age. Last count on Short Hoods was 13 in possession.
Reply:Originally Posted by kctgbSet your welder for the thick plate and just grab the edges of the thinner square tube. Use the thick plate to absorb the heat and every time you make a circle pattern just slightly go into the thinner tubing but don't stay on the thin tube for a long time. That's how I would do it.
Reply:Originally Posted by soutthpawBasically use a setting closer to the thinner metal. But torch angle and movement makes the biggest difference.  It needs to be angled into the thick plate then wash the weld puddle up into the thinner plate.
Reply:Originally Posted by kctgbSet your welder for the thick plate and just grab the edges of the thinner square tube. Use the thick plate to absorb the heat and every time you make a circle pattern just slightly go into the thinner tubing but don't stay on the thin tube for a long time. That's how I would do it.
Reply:Originally Posted by hobohiltonI'd set my machine for the thicker metal and use a technique to "wet" the puddle over onto the thinner metal.Think of trying to oxy/acetylene weld different thicknesses. You would still have to get the thicker metal up to heat.Thanks,Hobo
Reply:Originally Posted by DSWThis would be the "preferred" method. However someone who is not great with mig might find running slightly colder to be a help, say split the difference, since this isn't a critical item and all you really have to do is "glue" the two pieces together.I'd get some scrap the same thicknesses and do some practice welds 1st to tune things in. If you are finding it difficult to push the puddle up onto the thinner piece while keeping most of the heat on the 1/4", then try running one or two voltage taps lower and see if this helps. Since this is "art" you can most likely get away with a colder weld that doesn't burn into the 1/4" plate all the way.
Reply:Are you stripping the scale off the 1/4" plate before you weld it? Fusion will not be so good if not.Weld like a "WELDOR", not a wel-"DERR" MillerDynasty700DX,Dynasty350DX4ea,Dynasty200DX,Li  ncolnSW200-2ea.,MillerMatic350P,MillerMatic200w/spoolgun,MKCobraMig260,Lincoln SP-170T,PlasmaCam/Hypertherm1250,HFProTig2ea,MigMax1ea.
Reply:Your welds don't look bad but make sure you clean all metal to be welded with a grinder. Mig welding has to be clean for it to be a good weld.Also if you are welding left to right always use counter clockwise circles and if welding right to left use clockwise circles. I assume you are using a drag method for welding. good luck and have fun.Last edited by kctgb; 09-10-2012 at 09:49 PM.
Reply:One habit you should get into is not starting/stopping at a corner. For what you will probably be doing it won't matter, but the corner like the one front and center is a place for cracks to start. get in the habit of wrapping the corner and starting/ stopping on the flat and overlapping the welds so they tie in well. You can grind your stop/start some so they blend a bit better if you want..No government ever voluntarily reduces itself in size. Government programs, once launched, never disappear. Actually, a government bureau is the nearest thing to eternal life we'll ever see on this earth! Ronald Reagan
Reply:Those welds will be good enough for a sculpture piece I imagine. That is the difference between a weldor and a hobby welder. He may not be able to actually read and react to the puddle. But with more practice and playing more with the settings and different techniques, you will get the hang of it.
Reply:Originally Posted by shovelonAre you stripping the scale off the 1/4" plate before you weld it? Fusion will not be so good if not.
Reply:Originally Posted by kctgbYour welds don't look bad but make sure you clean all metal to be welded with a grinder. Mig welding has to be clean for it to be a good weld.Also if you are welding left to right always use counter clockwise circles and if welding right to left use clockwise circles. I assume you are using a drag method for welding. good luck and have fun.
Reply:Originally Posted by DSWOne habit you should get into is not starting/stopping at a corner. For what you will probably be doing it won't matter, but the corner like the one front and center is a place for cracks to start. get in the habit of wrapping the corner and starting/ stopping on the flat and overlapping the welds so they tie in well. You can grind your stop/start some so they blend a bit better if you want.
Reply:Originally Posted by BlackGT97Those welds will be good enough for a sculpture piece I imagine. That is the difference between a weldor and a hobby welder. He may not be able to actually read and react to the puddle. But with more practice and playing more with the settings and different techniques, you will get the hang of it.