What is MIG Welding?
MIG stands for metal inert gas. This type of welding refers to the use of electricity to melt and fuse pieces of metal together. Out of the various welding styles MIG is probably the most basic of all. With this technique, a wire electrode is used to create a flaming arc that generates heat and creates filler material. While this is happening, an inert gas is released around the area of the weld to keep out external contamination.
Applications for MIG Welding
MIG welding can be used for common household projects such as repairing a metal fence, swing set, or automobile.
About This Article
This is not an exhaustive guide to every MIG welding scenario. If you are new to welding and unsure about your material, equipment, or technique, please consult an expert. The following article is a series of guidelines that will provide basic welding information but is not a substitute for an expert's on-site advice. Additional resources are included at the end of this article for beginners ready to take the next step. If you're new to welding, read extensively about welding safety practices and the basics of MIG welding.
Why Use MIG Welding?
MIG welding requires a low skill level, produces a relatively clean weld, and offers versatility. Learn more about the advantages and disadvantages of MIG welding.
Materials needed for MIG Wedling
Setting Up
Selecting the right MIG welder for the job is probably the most important thing you can know. MIG welders come in a 1-Phase, Combination 1 & 3 Phase, and 3 Phase. 1-Phase MIG welder typically has a 115 or 230 VAC and is used in home garages, body shops, on farms and ranches, small maintenance, general repairs, and light fabrications. The 1 & 3 Phase MIG welders provide greater flexibility when welding. They are great for all the same things as mentioned in the 1-Phase MIG welders and can also be used in light manufacturing. The 3-Phase MIG welders are generally used in manufacturing and fabrication.
Depending on what you're welding, you'll need to choose the right kind of wire (see our suggested wire thickness chart) and polarity settings in order to make your weld strong enough.
Open the side of your welder and insert the spool of wire inside. As you remove the tip of the wire from the spool, make sure you hold it tight and prevent it from unravelling. The wire is wound tightly, and be sure the wire remains neat, tight, and unobstructed as you feed it. Cut off any bent ends and feed the straight part of the wire into your welder. Many MIG welders say the wire feed is where the majority of their problems occur. If you encounter problems feeding your wire through the welder, the wire liner may need to be replaced.
Roll the wire from the top of the spool into the hose of the welder, turn on the welder, and squeeze the trigger on the handle so that it comes out the end of the tip. When the wire comes out of the welder, cut it so that only a quarter inch is sticking out. Attach a gas cylinder, your shielding gas, to your welder's regulator and hose if your project requires it (see our MIG Shielding Gas Selection Guide).
Use your angle grinder and sand paper to clean all of the metal you're welding in order to ensure that the weld is strong and that your torch is not mixing with any chemicals on the metal. Using a welding torch on certain chemicals can create toxic fumes that can easily be avoided by careful preparation of the metal. Clamp the metal down on the table. Be sure the metal cannot separate while welding the two pieces together. Connect the grounding clamp to the metal to ensure you don't receive a shock at any point in the process.
While welding, wear goggles, a mask, a heavy jacket (such as a leather jacket), gloves, long pants, and closed toe boots. MIG welding results in sparks and UV rays that can cause serious skin damage.
Basic Welding Techniques
Turn on your welder and open the gas cylinder. Check with an expert on the proper gas setting for your particular project. Set your wire feed and voltage according to the metal you're welding (For example: use a wire speed of 30 and voltage of 2 for thin metal such as auto repair). Double check your clamps on the metal and your grounding clamp.
Hold your torch at a twenty degree angle from the metal with two hands, making sure your hands aren't too close to the weld. Position your metal so that you have a clear line of vision while working. As you weld, move the torch in a slight zig zag between the two metals. This technique will vary depending on the distance between the two metals. Some welders suggest moving the torch in an arching zig zag that looks like ocean waves curving back sharply.
Many welders begin with a basic "butt" weld. There are two common methods for moving the torch:
Push Technique: Pushes the torch forward, into the weld.
Pull Technique: Drags the torch backward. This is a common and simple way for beginners to weld.
When the two metals are too closely aligned, welders begin with a "tack" weld. Each tack is a small spot weld with an inch spacing between each tack. Tacks will hold the metal in place and make a cleaner weld possible.
Before setting to work on your project, test your weld on scrap metal to make sure both your techinique and power settings are appropriate. If you can snap the weld apart, then you need to adjust your settings. See our article: Causes and Cures of Common Welding Troubles and diagnose common MIG welding problems at our blog Weld My World.
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Written exclusively for Bakers Gas and Welding by Ed Cyzewski | 
