What is MIG?

MIG welding is a welding process that was originally developed back in the 1940′s. This process is designed for welding aluminum and other non-ferrous metals. MIG welding is an automatic or semi automatic process in which a wire connected to a source of direct current acts as an electrode joins two pieces of metal, as it is continuously passed through a welding gun. A flow of an inert gas (originally Argon) is also passed through the welding gun at the same time as the wire electrode. This inert gas acts as a shield, keeping air borne contaminants away from the weld zone.

Pros and Cons of MIG welding:

Some advantages of MIG welding include:

• It allows metal to be welded much faster than traditional welding “stick welding” techniques. This makes it ideal for welding softer metals such as aluminum.
• Since the shielding gas protects the welding arc, MIG welding produces a clean weld with very little splatter.
• The versatility of MIG welding means it can be used with a wide variety of metals and alloys
• The ability to join a wide range of metals and thicknesses
• All-position welding capability
• A good weld bead
• A minimum of weld splatter
• Easy to learn

However, its disadvantages are as follows:

• The welding equipment is quite complicated because it demands a source of direct current, a constant source and flow of gas as well as the continuously moving wire electrode. In addition, electrodes are available in a wide range of sizes and made from a number of metal types to match the welding application.
• The actual welding technique used for MIG welding is different from traditional welding practices, thus, there is learning curve associated with MIG welding even for experienced welders. For example, MIG welders need to push the welding puddle away from them and along the seam.
• The necessity for the inert gas shield means that MIG welding cannot be used in an open area where the wind would blow away the gas shield.
• MIG welding can only be used on thin to medium thick metals
• The use of an inert gas makes this type of welding less portable than arc welding which requires no external source of shielding gas
• Produces a somewhat sloppier and less controlled weld as compared to TIG (Tungsten Inert Gas Welding)

Furthermore, this type of welding is very useful because you can use it to weld many different types of metals: carbon steel, stainless steel, aluminum, magnesium, copper, nickel, silicon bronze and other alloys.

Now, we are going to learn how to MIG weld one of the soft metals – the aluminum.

MIG Welding – How to do it

Aluminum MIG welding is much harder than standard steel welding primarily because aluminum is a much better conductor of heat. As a result, its easier to melt the entire aluminum work piece while creating the weld. Therefore, Aluminum MIG welding requires more precise control over the arc temperature and the electrode feed rate.

Materials Needed:

• Electrodes
• Shielding gas
• Welding gun
• Welding machine

Instructions

1.      Choose the shielding gas. Aluminum welding typically uses a shielding gas of pure argon. Steel welding typically uses a blend of argon and CO2, so you may need to replace any regulators that are made specifically for CO2.

2.      Pick a MIG welding machine for aluminum. The welding machine must have more voltage so that it can form the welds more quickly. A 115 volt feeder is adequate for an aluminum work piece that’s up to 1/8 inch thick and a 230 volt machine can handle aluminum that’s up to ¼ inch thick.

3.      Use electrodes of the right alloy and thickness. Thinner electrode wire is more difficult to feed while thicker wire needs more time to melt. In the case of aluminum, there is an extremely narrow range you should use. Electrode wire for aluminum should be 0.035 inches in diameter. The most common alloy is 4043 aluminum and harder alloys like 5356 aluminum may also be used occasionally.

4.      Feed the electrodes wire with a feeding kit specifically designed for aluminum. These kits should include contact tips with larger holes than would be used for steel wire of the same diameter because aluminum expands more than steel when it’s heated.

5.      Weld as quickly as possible. Use a single, straight pass on each weld to prevent the entire work piece from overheating and possibly melting.

Over the years, the industrial life has been much easier and convenient because of inventions and innovations. Though each of them owns respective pros and cons, what matters most is that we learn how to use them correctly for our protection.

Welding is a skill that needs to be developed over time, with a piece of metal in front of you and with a welding gun/torch in your hands. MIG welding is sometimes referred to as the “hot glue gun” of the welding world and is generally regarded as one of the easiest type of welding to learn.