MIG welding is often described as a simple “point and shoot” technique for welding. However, depending on the size of the weld joint and the material being welded, different torch movements will be required.
There are many effective ways to move a MIG welding torch, with each being used for particular applications. When welding a thick metal such as steel, it’s typical to weld in a series of cursive “e’s” so that your torch loops back on itself. For a thin metal such as aluminum, the torch will be pushed straight across the weld joint. And then welding uphill is quite another matter.
Here are the specific tips for each kind of torch movement:
MIG Welding Thick Steel
A good way to make sure you’re inserting enough material and penetrating the metal deep enough is to MIG weld with a series of cursive “e’s” where the torch overlaps back into the weld puddle before moving forward. Be careful not to overlap too far on the sides of the metal as you move your torch. Also, keep the torch moving at a steady rate in order to avoid adding too much filler to the weld puddle.
Another variation of this method is to slightly overlap your torch movements like a cursive “i”, touching your torch into the edge of the weld puddle before moving ahead. This will increase your welding speed and prevent you from adding too much material to the weld puddle.
MIG Welding Aluminum
Aluminum requires a very simple push technique where the torch is pushed straight along the weld joint. Since you’re using a shielding gas for MIG welding, a slight torch angle of 10-15 degrees while you’re pushing the weld puddle forward will permit the shielding gas to clean the metal before your filler wire is melted into the weld joint.
Weaving or moving in cursive “e’s” will get the aluminum too hot and add too much filler. Some welders use a short stitch technique that provides a middle of the road option for a wide gap, but many experts suggest using stringers for aluminum. In addition, keep in mind that pushing the weld puddle will give you the best looking weld. Pulling will leave burn marks alongside the weld.
MIG Welding Uphill
We recently posted some MIG welding uphill tips over at the Quick Welding Tips blog, but by way of a recap, there are two basic ways to MIG weld uphill—which is the best way to get a strong weld on a vertical joint. One method is an upside down “V” motion where the torch traces the edge of the weld puddle, pausing briefly on the sides and moving right across the center.
The other method traces the weld puddle in a triangle motion that overlaps the weld puddle a little more, but generally produces the same results with possibly a little more of a crown to the finished weld.
MIG welding is a very simple process, but if you want a strong weld that isn’t full of lumps or holes, make sure your torch movement matches the metal and weld joint for your particular project.
