Welding can be loosely defined as the joining of two metal pieces. MIG welding, specifically, uses heat to melt the two pieces together along with a wire. This third, filler metal is fed through the gun (the heat source) into the weld. The melted metals cool together, creating what should be a strong joint.
Almost any combination of metals can be joined by MIG welding, but the strength and durability of the joint is determined by the wire used. A careful examination of the metal(s) being welded will lead to the best choice of wire, also known as the electrode, for the weld.
Common Metals for MIG Welding
As previously mentioned, MIG welding can weld most metals and metal alloys (a metal alloy is one piece composed of two or more types of metal). The three most commonly used metals in MIG welding projects are carbon steel, stainless steel, and aluminum, although aluminum requires a special setup and is not nearly as common as the other two. The metals being welded together are often referred to as the base metals. The composition and thickness of the base metals are what determine the proper composition and thickness of the electrode wire.
Selecting the Right Wire Metal
Typically, the wire should be the same type of metal as the metal to be welded. Stainless steel wire should be used to weld stainless steel and aluminum wire should be used to weld aluminum, and so on.
Many MIG wires are manufactured to include elements other than the primary metal. These elements, such as manganese, silicon, and titanium, help to deoxidize the weld, making it less porous and therefore more stable. Steel wires are also often coated in copper to prevent oxidation. The amounts of these extra elements vary from wire to wire and will have an impact on the stiffness of the weld puddle. Refer to the wire’s primary metal when making your selection, and don’t be put off by the presence of these stabilizing metals. If you’re unsure of your wire selection, research your options before purchasing, or speak with a knowledgeable salesperson at your local welding supply shop. Lincoln Electric also offers a ‘Consumable Selector’ guide on their website; Please note that the selector’s results will recommend solely Lincoln products, but their recommendations could easily be used to select a similar product from another brand if that is preferred.
Selecting the Right Wire Thickness
The second aspect of wire electrode selection is the thickness of the wire. The thickness of the base metals being welded together determines the proper diameter for MIG welding wire. Many manufacturers include wire thickness charts in their wire product packaging and on their websites.
Other Pointers for MIG Wire Selection
- A range of thicknesses work for each standard wire diameter, so it’s still possible to get the right wire diameter for a project even if the exact gauge of the plates being welded is unknown.
- Wire is often sold by weight rather than length of wire on the spool. Generally it is more economical to purchase heavier spools, especially for frequent welding, but factor your welding habits into your decisions about how much wire to buy. Select an amount that makes sense for your own purposes, rather than buying the cheapest price-per-inch spool that will not be used.
- September is Lincoln Month at Baker’s Gas, and BakersGas.com now offers Lincoln MIG welding wire. Visit the product page to learn about select Lincoln wires, their features, and their typical applications. All Lincoln orders placed in the month of September are entered in sweepstakes for one of three great prizes. The current special prices will expire at the end of September, so stock up soon!