How MIG Aluminum Welding Works How MIG Aluminum Welding Works

MIG aluminum welding can be considered to be both a skill and an art form. A good welder can work very quickly and leave a smooth weld along two pieces of aluminum. It’s a complex procedure but the welds produced have to be very clean. MIG aluminum welding requires a lengthy learning curve and nobody becomes an expert overnight. It can be a challenging task even to experienced welders.

What iS MIG Welding?

MIG stands for metal inert gas and is a technique used on soft metals such as aluminum. Welders use a welding gun which can be set for automatic or semi-automatic use depending on the job requirements. The welding gun contains a feed of wire and is connected to an electric current.

The heated wire joins the two metals together, making for a long, continuous seam. The inert gas also passes through the welding gun. This is necessary in MIG aluminum welding to ensure no contaminants enter the weld and this ultimately leaves the join looking cleaner and smoother.

Inert Gas

MIG aluminum welding has progressed since it's early days. Back then, the biggest problem was finding a good inert gas that would work for welding. Nowadays, the industry uses carbon dioxide as a protection against contaminants in the weld. It’s a cheap and readily available alternative to most inert gases although pure argon is best for welding aluminum.

However, the fact that MIG aluminum welding relies on inert gas as part of the process does create problems. The welding has to be conducted in areas without wind so the gas doesn’t disperse particularly quickly. Because welding cannot really be done outside unless the conditions are exceptionally good, this makes the task restricted to indoor use and potentially dangerous gas can fill the air. Suitable safety equipment should always be worn.

Learning to Weld

There are several things to master in MIG aluminum welding. The welder has to be able to maintain a steady, even bead of wire to join the metals together as well as dealing with the amount of gas and electrical current being fed. Additionally, the nozzle of the welding gun has to be at a specific angle for optimum welding which requires a great deal of control.

This makes MIG aluminum welding very different from spot welding which is often used on iron and harder metals. Because the process is relatively fast, it doesn’t bore holes in the aluminum.


The wire used in the weld is fed from a spool through to the welding gun. The electrode on the tip of the welding gun provides the electricity that melts the wire so it can be applied to the aluminum. A successful weld requires the electrode to be held a constant distance from the metal and at the right angle. The shielding gas protects the weld as it cools, which happens very quickly.

MIG aluminum welding is very simple in principle but learning how to do it well takes a lot of time and practice. Once the weld has been completed, it still needs to be ground down to the point where it’s totally smooth to give a great appearance.

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