MIG welding came into existence during the WWII and was created for the faster production of equipment and weapons. Post war, the process was still popularly used in large factories and workshops.
In ARC or stick welding, the flux around the electrode melts and a gas is formed which shields the puddle from the surrounding air which contains nitrogen, hydrogen, oxygen and other gases that can contaminate the weld pool and cause weld defects.
MIG stands for metal inert gas. For MIG welding, a solid-steel wire spool is fed via a liner and then from the contact tip of the MIG gun. The tip of the welder is electrically charged and is hot and when the trigger is pulled, the wire melts to form the weld puddle.
In the case of short-circuit welding, small drops of molten wire get heated when short-circuited and flow to generate a puddle when touching the base metal. The weld puddle is shielded from the atmosphere by the inert gas flowing out of the welding gun.
In MIG, the inert gas does not combine with any other element and so, inert gases such as argon and helium were used initially. Later, it was discovered that carbon dioxide also worked equally well, although it is not an inert gas and this type of welding came to be known as GMAW or gas metal arc welding. Typically, MIG welding is used in factories and engineering shops.
Buying a MIG Welder
When buying a new MIG welder, you must consider the following factors such as its maximum and minimum amperage, maximum and minimum weld thickness, duty rating warranty period and type, whether it has a return, pick up or return to base type of warranty.
Advantages and Disadvantages of MIG Welding
MIG welding has several advantages such as it offers higher productivity and you do not have to stop your welding to change the rods or brush or chip the weld frequently, the learning curve for MIG welding is quite shallow, it is very easy to understand and produces good-looking welds, the process does not require any clean up, can weld on aluminium, mild steel and stainless-steel.
Some of the disadvantages related to MIG welding is that it needs a bottle of shielding gas, requires you to spend money for the consumables such as nozzles and tips. Welding cannot also be done on dirty, rusted or painted surfaces and you need to clean the metal properly before you begin to weld and MIG welding is not suitable for thick steel as you cannot get proper penetration.
In short, MIG welding is quite an easy and popular process. It can be learned very easily and is very versatile and can be used for various projects as the learning curve is not very steep. And, the best part is that you can set up a MIG welding unit easily, even in your garage in your home or workshop and start welding.