Different wall thickness tubing question

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I am ready to tackle my first project with my MIG, my only experience so far has been an O/A class at the community college.  I need to weld a short section of .120 wall mild steel tubing perpendicular to a long section of .065 wall mild steel tubing.  The short .120 tube is on top of the .065 tube, not notched and level with it.I've already sourced a bunch of scrap in these sizes to try to get it dialed in before I try it on the pieces I intend to keep.  But before I get started I have some questions.  I'm hinking I'm either going to have problems with burn through on the .065 in order to get penetration on the .120, or in the other instance having good penetration on the .065 but nothing into the .120.Is there a technique that I can use for welding metals of dis-similar thicknesses?In my O/A class we never welded any metals that were not the same thickness, so I can't draw from any technique learned there.
Reply:regardless of mig/stick/tig/oa...direct the heat into the thicker metal and let the puddle flow over to the thinner metal
Reply:That's kinda what I thought, just double checking.  Hopefully I can get it down with all the scrap I have, then the real deal wont be too much of an unknown.
Reply:When welding thick to thin all you need is enough penetration equal to the thickness of the thinner metal. Any more is just waste and can be detrimental to the joint..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:So when setting up I should set amperage for the .065 pieces?.030 wire?
Reply:A fillet weld does not require any more penetration than what is required to fuse the filler metal both legs of the fillet and consume the corner at the root of the joint.