MIG welding was developed in the mid-twentieth century to join non-ferrous metals and aluminum. The technology has evolved since being invented in the 1940s given the process a greater range of uses such as steel welding.
Video: How a MIG Welder Works
What is MIG Welding?
Metal Inert Gas, abbreviated as MIG, is a semi-automatic process that requires electrodes, an inert gas and a welding gun with a feeding wire to carry out welding of metals thicker than 1/16 inch or more.
The process, because of its’ many advantages, has always been a method of choice for domestic and industrial welding both. A MIG welder, with a continuous feeding wire, makes welding less troublesome and possible in all positions.
It is also called GMAW or gas metal arc welding or arc welding.
Though it sounds easy MIG Welding is actually a bit more technical and cautious than others.
MIG Welding Equipment
A MIG welder contains a handle with a trigger to allow constant feeding with a wire or electrode. This wire is similar to the brake cables used in bicycles. The continuous feeding is essential for burning and fusing the base and parent metal together. A MIG welder can easily weld stainless steel or aluminum using argon and CO2 blend. The use of nonstop feeding process makes this type of welding easier and safer as compared to other processes. Cleaning is easy in this case. Since it generates less smoke, it’s therefore liked by all. It is very cost effective and fast as well.
Though it sounds easy, it is a bit more technical and cautious than others. It demands you to be more careful during MIG welding. Also, the demand for maintenance is high in MIG welding. A MIG welding gas supply is also necessary all the time which sometimes become a hassle. It can’t operate well on rusty metal. Also, a MIG welder requires multiple accessories to support its functioning.
Apart from few hassles, the benefits of MIG welding can’t be overlooked. But the selection of the most appropriate MIG welder is crucial in this regard. It requires an understanding of the essentials of MIG welding that makes a choice a better decision. Beginners should become familiar with the functioning capacity of the machine first.
Basics of Choosing a MIG Welder
he selection of a right MIG welder for your needs is determined by many factors. Below is an overview of such basics.
- Amperage and TimeThe MIG welder is available in different types, depending on the amount of heat or amperage required to be produced for a particular period. In the case of light or thin metal, which needs less time for heating, a light-duty welder is a good choice. But thicker metals require nonstop heat for a long time which is possible with heavy duty gun. The difference in both types of guns is also found in their purchasing prices as well as the maintenance required for them. Light duty guns are required to be replaced more frequently as compared to heavy-duty guns.
- Selection of MIG Welding GasThe ideal combination of 25C or 75% argon and 25 % CO2 blend is a well-known “all-purpose” blend. For deeper penetration into thick metals 100% CO2 is required.Some MIG welders can also work with flux core welding wire only for feeding purposes. The MIG welder needs to hook up to a gas cylinder somehow. The cylinder is required because the shielding gas helps in producing an excellent weld without slag coating. Therefore, it is better to look for a MIG welder that can be connected to a gas source.
- MIG Welding VoltageBefore choosing a MIG welder, it is equally important to have the right electric outlet. A typical home-based 110 volt MIG welder is best suited for light metal welding as it can be easily plugged into a usual domestic electric outlet. A 220-volt welder is required for heavy welding. Any fluctuation in electric supply may affect the feeding process.
- MIG Spool GunA spool gun MIG welder is a preferable option if welding of aluminum is desired. It is not available for all MIG welders. An optional spool gun is also available to be connected with a MIG welder such as Longevity MIG 140.
MIG Welder Spool Provides a Continuous Feed Through the Welding Gun or Torch
- MIG Wire SelectionMIG wire selection is vital to effective MIG welding. Tensile strength is required to be attained during MIG welding using an appropriate type of wire. ER70S-3 is an ideal wire for base metal with a clean and oil-free surface. ER70S-6 is better suited for metal with surface contaminants. The deoxidizer makes the transition easy from weld to metal in this case.
MIG welding wire acts as an electrode and is fed by a spool. The wire is fed continuously.
The wire diameter and its composition are also critical to consider. An oversized wire may make feeding difficult and tip blockage. An undersized wire also erodes the tip. Hence consistent diameter is very important for a constant flow of current. The wire must be changed if it is found rusty. A rusty wire also causes an interruption in feeding.
- Cooling MechanismAnother essential feature to look for in a MIG welder is whether it is air-cooled or water-cooled. The heat over the metal requires being dissipated either through air or water. In the case of light-duty welding, air cooling is sufficient where ambient air and gas can cool down the metal. Water-cooled guns are recommended for continuous long welds with 300-600 amp. But these guns are expensive and difficult to operate and maintain as compared to air-cooled guns.
- Cost EffectivenessWhile deciding about which MIG welder to choose, the welder with a complete package must be your choice. From the matter of cost to arc quality, everything counts in a MIG welder. The MIG welders with the most reasonable to the most expensive price ranges are available in the market depending on the features. The one you select must comply with your needs and purpose. It is not just the cost of the welder to be counted, but also the accessories along with it count too.
The effectiveness of weld through MIG welding is thus dependent on the appropriate selection of welder. The MIG welder with the above-stated features will not only make welding easier but also results in a better quality of metal welding.
The better you understand the nitty-gritty of this machine, the more enjoyable the welding process could be for you.
FAQ
Should the contact tip on a MIG gun stick out or be recessed?
The answer depends on the type of metal transfer mode you are using such as pulse transfer, globular, spray, or short-circuit. Each mode has a different contact tip positioning. For example, if using a spray transfer more, more heat is generated on the contact tip than when welding in short-circuit mode. The distance from the contact tip to the work varies based on the transfer mode.
Most MIG welding done at home is short-circuit transfer welding. Spray mode is utilized for large welds or thicker materials. In short-circuit mode, the contact tip should stick out past the nozzle end about 1/8 inch. This enables the operator to visually see the tip, making it easier for the operator to maintain the core tip contact with the work and distance. Most nozzle setups are in a fixed position and you just screw them on. These are usually even with the nozzle rim. Some types have a recessed nozzle as they are tightened into position. In general contact tips are not recessed as this makes it hard to see and maintain consistent contact tips to work distance along with consistent amperage.