There are general rules for MIG welding that always apply, such as taking the time to determine the best amperage, set up a good ground, and select optimal wire feed settings. Failing to get those three factors right will cause most of your problems right there, and the main solution is to read up on the recommended settings for your MIG welding machine in order to test them out. However, MIG welding in certain positions will create specific challenges that you may not be able to overcome without specific advice for each one. Here are some tips for MIG welding in some unique positions.
Inside Corner Joint MIG Welding
The challenge with welding an inside corner is that you can have too long an arc and puddle both corners of the metal without actually fusing the metal in the middle effectively. Controlling your arc length while maintaining a good enough stick out is the key to welding an inside joint without created a mess of melted metal.
Some basic guidelines for welding any corner include ensuring that you’re adding an amount of metal to the weld that will create an appropriate-sized weld joint (a thickness that is similar to the metal’s thickness) and the metal is clean to begin with. “Over-welding” adds too much metal to the joint and can create a sloppy weld and even cause burn-through if you’re using too much power.
Outside Corner Joint MIG Welding
How you move the torch makes all of the difference in the world. Take a dry run along the weld joint to make sure you’re going to be able to weld comfortably no matter what your position may be. In order to effectively weld an outside corner joint, you’ll make a simple circling motion that traces the front edge of the puddle. Outside corner joints will usually need to be clean and orderly, so the tighter you trace the puddle, the better.
Jody at Welding Tips and Tricks recommends keeping a short electrode stick out and running the machine hot enough to achieve excellent penetration into the weld joint. In fact, many MIG welding problems can be resolved by keeping a short stick out. Too much electrode stick out will pile on the material and leave a messy weld. However, you can also modify your technique and weld with a kind of “t” motion that goes into the center of the joint and then moves up each side before moving down the center of the joint again. That technique calls for lower settings in order to keep the metal from burning through.
Overhead MIG Welding
When welding overhead you’ll once again need to run your machine on the upper end of the recommended settings and keep your electrode stick out short. However, you’ll also need to really watch your torch angle in order to make sure you keep the electrode pointed right in the weld joint. Keep the torch angle to a minimum, rarely angling it more than five degrees if at all while MIG welding overhead.
Uphill MIG Welding
MIG welding can be extremely effective for uphill weld joints where you need to focus on moving your torch in either an inverted “V” or triangle motion. The key to MIG welding uphill is to build your weld on top of itself, tracing the front of the puddle. If you the triangle motion, you may add more material to the weld and develop a slightly higher crown on the weld joint.
Keep in mind that vertical joints can be welded together by welding downhill, but you won’t achieve the same strength when welding downhill when compared to a more methodical uphill welding technique.
MIG Welding for the Right Joint
Dragging your weld bead will give you more penetration and a narrower weld. This is ideal for narrow weld joints. For wider weld joints, push the torch in order to widen your weld. Keep in mind that you’ll lose penetration with the push technique. Though some welders swear by one method or another, both yield fairly similar results for typical horizontal positions. Keep these guidelines in mind for particularly wide or narrow weld joints, but otherwise, you can generally use the technique with which you feel most comfortable.
MIG Welding is simple and effective, but it is not without its challenges. By taking your time to select the right settings, to learn from your mistakes, and to match your technique with the particular job in front of you, you’ll develop a proficiency for whatever jobs come your way.