TIG vs MIG: Which Welding Process to Choose?
1 or 0 and 1
The major difference between MIG (Metal Inert Gas) and TIG (Tungsten Inert Gas) welding derives from the difference in the type of electrode used to generate the arc. The arc creates heat which melts the filler metal into welding plasma. In MIG welding, the electrical current runs through the filler wire so it acts as both the electrode and filler metal. This method produces plasma at a single point. In TIG welding, the electrode and filler metal are separate and must be joined together during the welding process, requiring two contact points.
Do You Prefer Automatic or Manual?
When comparing the two welding methods, it might help to think of MIG as an automatic gear shift car and TIG as a manual gear shift car. MIG welding is easier, faster, and more versatile and is the popular choice for beginners—much like an automatic gear shift. TIG welding requires more skill and takes longer but allows for greater control over the process—much like a manual gear shift. Both types of welding use a gas shield that pumps through the nozzle to protect the weld from contaminants in the air.
With MIG welding, an arc is formed from an electrical current that runs through a continuous spool of wire that feeds directly through a handle and out of the tip of the nozzle, much like a glue gun. The wire acts as both an electrode and metal filler. This method requires pressure on the trigger which pushes out the filler wire that melts into plasma as it hits the arc. You must control the size of the arc by adjusting the distance from the tip of the nozzle to the plasma at the welding point. MIG welding can be used for a variety of applications but will sometimes burn through on thinner gauged, delicate materials.
In TIG welding, the electrode and filler wire are separate. The electrical current in a TIG runs through a tungsten metal rod with a handle that is gripped like a large marker. The filler metal comes in the form of rods. Since the electrode and filler metal are separate, you must use two hands, one to hold the electrode nozzle to create the arc, and the other to feed the filler metal. You have to manually feed the filler metal into the arc using your fingers. This requires a bit more dexterity and control. The TIG method is slower and more difficult to master but does give you more control over the process.
TIG Set Up
TIG welders need more setup time as well. In order to create an arc, you must first manually grind the tip of the tungsten electrodes to a sharp point. Ideally, you’ll use a dedicated wheel of a shop grinder so that you don’t contaminate the tip with foreign material that may be left over from an earlier project. While welding, you must be careful not to dip the point of the electrode into the plasma; this contaminates the arc, resulting in the weld not forming properly. Once the electrode becomes contaminated, it must be replaced.
TIG Set Up
With TIG welding, you need to be able to feed the metal rods into the arc using your fingers. At the same time, with your other hand, you have to control the size of the arc by maintaining the proper distance between the electrode and welding point. It takes a lot of practice to get it right and for this reason, this method is more difficult than MIG welding. Though TIG welding is more complex, it does allow for welding thinner metals and more delicate work. If you are looking to weld to get a variety of tasks accomplished quickly, I would recommend the MIG. If you want to deep dive into welding, I would recommend the TIG. If you are having difficulty choosing one, there are now some welding machines available that have a conversion option so that you can do both.
Header image credit: jason gessner, Flickr