The Sealey Buyer Guide to MIG Welders
MIG welding involves a wire fed from a spool in the welder unit, which runs through a hose to a handheld torch. The wire performs two jobs; it supplies voltage to melt the metal being welded, and acts as a filler. The process offers high productivity, as the wire is continuously fed.
Gas is used to shield the weld from impurities which would cause the weld to be porous and weak. The gas is fed from a gas bottle mounted on the welder unit, up through the hose to a gas cup at the end of the torch. The gas can be easily blown away, particularly if you are working outdoors, resulting in poor quality welds. In recent years, Gasless MIG welders have become popular. They use a specialised flux coated wire to shield the weld, enabling them to be used outside.
Types of Gas & Industrial Gas Supply
There are three types of gas used:
- CO2 Carbon Dioxide - used for mild steel.
- CO2/Argon - A mixture of 20% Carbon Dioxide and 80% Argon which gives a smoother and cleaner weld than pure CO2.
- ARGON - Pure Argon which is used for aluminium.
If you plan to run your machine on gas, you need to consider how much welding you plan to do. Lower amperage machines tend to use small disposable or re-fillable bottles. If you plan to do a lot of welding, a large industrial gas bottle will be more economical. However, your welder will need to be converted to cater for the larger bottles. Larger amperage welders are designed for use with industrial gas bottles.
Environment & Power Supply
The first consideration when purchasing a MIG welder is where you intend to weld. If you plan to work outdoors, you need to purchase a MIG capable of gasless welding. Usually, these machines can be easily converted to run with or without gas.
Secondly, you need to consider the power supply available in your workplace. Some machines can be run on a conventional 13Amp domestic supply, while others may require a 30Amp or even three phase supply. If you plan to weld thin metal, such as car bodywork, a lower amperage is all that’s required, therefore 13Amps is sufficient.
Torch & Hose
Larger MIG welders include welding torches and hoses with a bayonet type connector. This allows the user to easily change between hoses/torches, which is particularly important if you frequently weld different types of metal i.e., mild steel to aluminium.
Old school MIG welders have a permanently live torch, but most modern machines have a switch in the torch to turn on the voltage, feed the wire and turn on the gas supply. This is a safer and easier method and used in all Sealey MIG welders.
The duty cycle of a welder reflects how long it can weld in a 10-minute period before it must cool down. For example, a 40% duty cycle equates to 4 minutes of continuous welding. The higher you set the amperage, the shorter the duty cycle. If you plan to carry out a lot of welding, the duty cycle is a very important consideration when comparing electric welders.
View our current range of MIG Welders here:
Safety First! MIG welders create very hot temperatures and emit a very bright light, which can cause severe damage to both exposed skin and eyesight. Therefore, it is essential to wear the correct safety equipment.