Graham's Blog has a number of Mig Welder related articles including:
Gas vs Gasless Mig Welding
10 Tips to Improve your Mig Welding
Mig Welding Aluminium
Mig Welder Feed Roller Tension Adjustment
Mig Welding Gas
Mig Welder Wire Feed Speed
Gas Flow Rate for Mig Welders
Metal Inert Gas Welding (MIG) is, in most cases, an incorrect term as an Active Gas such as an Argon/Co2 mix, or pure Co2 is often used. In reality, the use of an active gas makes the process Metal Active Gas Welding (MAG). However, "Mig" has become the generic term used in the UK. In North America, the process is generally referred to as Gas Metal Arc Welding (GMAW).
However you choose to name the process MIG, MAG or GMAW, the process itself involves feeding a continuous wire electrode. From the end of this wire/electrode an arc is produced between the wire and the workpiece. This arc melts the workpiece metal, forming a weld pool. The wire is then used as a filler metal to form the weld. Shielding gas is poured continuously over the weld to prevent oxidisation.
Mig Welders are still the most popular choice of welding machine for the DIY welder and industrial fabrication shops. A Mig Welder is easy to set up, and once set, simply requires the operator to master speed of torch travel and arc length.
A Mig Welder is capable of mig welding Mild Steel, Stainless Steel and Aluminium, although Mig Welding Aluminium should only be attempted by the experienced Mig Welder and results are limited.
The key advantages of a Mig Welder are high weld speed, ease of use and low cost. Disadvantages of a Mig Welder include less control over quality, fairly hard welds and possible mechanical problems if the Mig Welder's mechanisms are not kept in good working order.
Choosing the right Mig Welder is a balance between how much you can afford to spend and what you want the Mig Welder to be able to do. There is no point in buying a 130amp Mig Welder to run off a 13amp plug if you want to weld 10mm steel, because that Mig Welder simply won't be powerful enough, so be realistic about what you want your new Mig Welder to do. If you need any help with this, please do not hesitate to phone and speak to our Technical Department. Another consideration when choosing a Mig Welder is torch type. Mig Welders either have a Fixed Mig Torch, that is to say it is bolted to the machine and wired in, or they have a Euro Mig Torch. A Euro Mig Torch is found on almost all professional Mig Welders; they tend to be better quality Mig Torches and the Euro fitting means they can be changed in under a minute. Essentially, the Mig Welder has a Euro Socket on the front that the Euro Mig Torch simply screws on to with a hand nut. Despite their better quality, most Euro Mig Welder Torches are cheaper than replacement Fixed Mig Welder Torches.