MIG welders are versatile and easy to use. With a little bit of practice, they can also be easy to set up. Your MIG welder’s user manual may contain recommendations for power settings and wire feed speed, but there are also a few universal setup guidelines to follow to ensure you end up with clean, strong welds.
Before you set up a MIG welder, it is important that you have a basic understanding about how one works. Metal Inert Gas (MIG) welding, also known as Gas Metal Arc Welding (GMAW), uses an electric arc and an inert gas to melt the metal being worked on. This molten metal combines with metal fed from the welding gun to form a weld “bead.” As the bead cools, it solidifies, forming a new section of fused metal.
Setting Up a MIG Welder
On a traditional MIG welder, there are three primary settings that you will have to adjust for each welding session: voltage, wire feed speed and gas flow rate. Even if you have a user manual or chart to guide you, it can help to take some time working with a scrap piece of metal to precisely dial in these settings.
- Voltage is the primary setting that determines how much heat is applied to the metal. Insufficient voltage will produce a weak weld, but too much voltage can burn completely through the metal being worked on.
- The wire feed speed setting controls how fast the wire is fed into the weld joint. This determines not only the amount of fill material left in the joint, but also amperage, since increasing the feed speed means more electrical current can be transferred into the metal being welded.
- A gas flow rate of 15 cubic feet per minute should be sufficient for most shops, but you may have to increase this setting if you are working in a drafty area. The gas shields the weld, enabling it to form in a clean, consistent manner.
Common Bead Issues
As you try different settings using your scrap piece of metal, pay close attention to the quality of the bead you are producing. A good weld will fully penetrate the base material without burning through it, have a flat bead profile, and adequately cover the joint. If you experience any of the following issues, adjust your MIG welder settings accordingly:
- Metal splatter
Solution: increase voltage and/or gas flow rate
Solution: decrease wire feed speed and/or voltage
- Excessively wide bead
Solution: decrease wire feed speed or accelerate gun travel time along the weld
- Narrow, convex bead
Solution: increase voltage or decelerate gun travel time along the weld
Once you have some practice adjusting the controls on your MIG welder, you will be able to use it with a variety of metals. MIG welders are compatible with aluminum, stainless steel and other steel alloys, which is what makes them so popular in collision repair shops.
While these metals can all be welded with a MIG welder, they will act differently when heated. Advanced welders, like the Chief MultiMig 522 and 511, offer preset weld programs and parameters to streamline each welding job. The programmable features found on these welders can make it easy to weld metals like aluminum and high-strength steel, which are increasingly being used on vehicle bodies.