Mig question

Welding overhead with my Mig is always a problem. The wire burns back into the tip and sometimes the nice crackling sound of the welding stops and you just hear a hissing sound. I thought it was me or my welder but, my friend who has been helping with the truck project experienced the identical problem while under his street rod welding in the new floor. He's running a Lincoln welder vs. my Hobart. What's going on. Is there some adjustment to make to the gas for overhead? Different wire like there are different rods for stick welding overhead? I've been fighting this for a while. Any help from the pros?

 

Wire does not come out enought faster...be sure that the tip is clean so the gaz can get out without any restriction

 

Inverted welding basicsDid I say welding UPSIDE DOWN? Boy I'll bet that got your attention. Really, these tips are for all welding done with the MIG. In fact, there really is no difference in welding upside down or laying flat, it is all in the mind where the difficulties come from. I have to say that I use to cringe when I saw that I had an inverted weld to do. Then all that changed I took the ICAR (a nation wide organization for standardizing repairs) welding test. It included two each of a plug weld (where you weld through a hole to the sheet below) and a "bead" weld. Both had to be done in a horizontal, vertical and inverted. That inverted was the only one I was worried about. Well I knew I would have to practice a LOT. The funny thing is I found the answer not so much in practice, but in studying HOW a MIG works (this can be found in my "Basics" of MIG welding) and I found out how important clean metal was. Don't get me wrong, the practice did it for me, however the understanding of how the MIG worked helped me more than anything. I had a basic idea how the thing worked, I mean come on, it is a direct short where a wire coming out of the gun melts into the metal because of resistance. I studied the science as well as the art of welding, so I really got a grasp on what exactly the wire speed did and what exactly the voltage did. For the first time I understood what was happening when that wire hit the metal. On the first official practice, I set up the work area just like it would be at the test site. I took sheet metal "coupons" about the size of a playing card, punched holes in a few for plug welds and started welding. The thing I noticed right off was that it really wasn't that hard, why? I was welding really nice welds including the inverted. These welds were much nicer than I do at work. It hit me that the reason was, I was sitting properly and the metal was clean. That was it, that was the magic. By the time I practiced a few hours and took the test I was welding like I never had before. I now prepare cars the same way I did those coupons, SPOTLESSLY clean. Now I weld the same way on my repairs. The thing is, there is a point where you can simply pull the trigger and you will weld. No burning holes (to speak of) no dripping molten metal, no popping and flying fireballs, you just weld. I have gotten so that I can weld "blind" with only the "buzz" as a guide. I trigger the gun with my thumb, index finger, left hand right hand, it really has changed things with me. Without the thorough understanding of how the MIG works one can not properly "tune" it. Creating the balance between voltage and wire speed is the key. With the proper balance, you literally point the wire where you want it and pull the trigger. It WILL weld perfectly (providing the metal is clean). With the proper balance you can hold the gun up against the metal without even moving it at all, pull the trigger and just...hold it welding away. The wire will feed into the molten metal at just the correct rate. The weld will not blow through because the wire melting into it will "keep up" with the rate of the melting and cooling (solidifying) metal​

 

Learn to work with gravity.I am sure you have learned that molten metal will run down. It will not run up or sideways, so you are one up on it already. If you know where it the molten metal "wants" to go, use it to your advantage. It is like using a long wrench over a short one, you can take advantage of the science of leverage or you can fight it, it is up to you. When welding a vertical weld you start at the top and go down. This way you keep the weld arc ahead of the molten metal. The molten metal will start to solidify staying in place behind the weld arc as you go. If you were to start at the bottom and go up, the molten metal would hang off the bottom of the weld arc. It will at the very least make for an ugly, lumpy weld, or at the worse cause the molten metal to fall right off the weld arc. You can "fool" gravity and go up that vertical weld however you will find that you will work with the gravity most of the time. This fact that molten metal will want to flow down is the reason you need your arc to start hot and fast. You need to "push" the molten metal into the weld when you are welding inverted. The arc has to be established fast on the base metal with the MIG tuned well. At that point you have the luxury of making a nice molten puddle that will not fall. Only then do you move "it" over to the edge of the overlying metal. This will produce proper penetration, which of course is the main objective. The weld needs to be well established in the base metal first, then only a little on the edge of the overlying metal is needed.​