MAG Welding Made Simple: What You Need to Know

Many welders use GMAW (Gas Metal Arc Welding) technique in their projects to fabricate high-quality structures. This method is based on using a metal arc, protected by a shielding gas, to weld different metal pieces together. GMAW can be divided into two main types, MIG and MAG welding.

Many new welders are confused about the difference between the two and asked us what is MAG welding?

MAG stands for Metal Active Gas. It is pretty similar to MIG welding in its application. The main difference is in the type of gas used. MAG welders generally use Carbon Dioxide or a mix of CO2, Argon, and Oxygen to get the desired result.

MAG Welding Basics

MAG welding is pretty similar to MIG and you can use the tips applied in metal inert gas welding to your projects when shielding with a metal active gas.

A MAG welding machine operates by supplying a constant voltage to the gun that holds the feeding wire. The electric current creates a plasma arc between the workpiece and the welding wire.

The arc heats up to a very high temperature and melts both the material that you are welding and the wire that is being fed through the spool. So the welding wire works both as the electrode and the consumable. This allows you to work a lot faster than TIG welding.

The welding wire is on a rolled-up reel that is placed in the welding machine and it is mechanically fed to the torch as it gets consumed. You can adjust the speed up or down, depending on how quickly the job needs to be. Adjustments in the feeding speed also affect the amount of power you need. It also affects the type of weld you will get.

The shielding gas serves two purposes here.

First, the active shielding gas used in this process is necessary to protect the molten pool of metal from the environment. If you didn’t have the shielding gas, the material would become way too hot and burn away.

Second, molten gas is used to protect the arc from becoming exposed. This helps maintain a uniform temperature that is necessary for accurate penetration into the base material.

What Projects Can Use MAG Welding?

MAG welding is a common welding technique that is used in a variety of industries. This method is quite versatile and allows you to get high-quality results. It is used a lot in the metal and heavy manufacturing sectors.

MAG welding process can be mechanized with ease, making it suitable for use in places where a high level of productivity is required. It is often applied in vehicle manufacturing plants at the industrial level. It is also popular with hobbyists looking to build their own leisure vehicles.

In MAG welding, you can also use a special gas-filled welding wire without requiring a separate source of gas. When this wire is combined with a compact and portable welding machine, it generates its own shielding gas.

This removes the need for carrying heavy gas cylinders around and makes this welding process a lot more appealing to hobby welders or DIY people who are looking for a machine they can easily move around.

What Materials Can You Work With?

The possibilities of welding with MAG are limitless, regardless of the type of materials that you want to join. You can use it for almost all kinds of ferrous and carbon steels as well as stainless steel of various thicknesses.

If you are looking to work with aluminum, you don’t need a pulse function for the welding machine. In such cases, the current can be set to alternate between the base current and peak current. This allows you to weld even a fragile material like aluminum in a very controlled way, without burning up the top surface.

In the case of welding higher alloy steels and aluminum, you can increase the volume of inert gases like helium or argon in your mix to reduce the intensity of the weld. The advantage of adding inert gases to the mix while MAG welding is that they allow you to meld with higher temperatures without oxidizing the material.

Where Can You Use MAG Welding?

MAG welding can only be used indoors or in enclosed spaces where you have ample protection from the wind. This is because the gases used in MAG welding don’t provide very good coverage like pure Argon or Helium.

Strong wind, moisture, and rainy weather can easily blow away the shielding gas and expose the welding bead to oxidation. This can create porosity and lower the quality of the final weld.

A weld formed this way would be of a lower quality, become rusted easily, and wouldn’t be able to bear load or stress.

Types of Arcs Used in MAG Welding

Four types of arcs are mainly used in MAG welding to weld metals together.

Short Arc Welding

Short arc welding is used if you are working with really thin metal sheets, delicate projects, and soft metals or if you are welding from a difficult position. A short arc weld produces a fine droplet, creates low sputter, and results in a smooth material deposit.

Long Arc Welding

The long welding arc is used for thick metal sheets and plates. It generates a long arc and uses a spatter-intensive technique that produces a coarse material deposit.

Spray Arc Welding

Spray arc welding is used by expert MAG welders or automated machines. It is used for welding together thicker sheets and plates with the help of an argon-based mixture of gases.

You can achieve a larger melting area on metal sheets and greater welding speed with spray arc welding. It produces a very low spatter and creates a fine droplet of material deposits.

Pulsed Arc Welding

The pulsed arc welding is used for all types of sheet and plate thicknesses. It uses shielding gases that are mixed with pure argon to increase weld and arc protection.

Pulsed current is supplied through the wire that creates droplets during the welding process. The speed of the pulses can be adjusted based on project requirements. The result is a uniform flow of fine droplets and very low spatter. It creates practically short-circuit free material deposits.

Benefits of MAG Welding

MAG welding is preferred by many welders because the shielding gases provide adequate protection against oxidation of the finished weld. This welding technique is quite clean and does not produce any slag during welding.

One of its benefits over MIG welding is that the working speed is very high. You can create more projects with MAG welding than you can with MIG welding.

The weld beads created with MAG are thicker and have a deeper penetration in both the base metal and joined arm. It produces a sturdier finish that can support greater loads.

Another benefit is that the welding machine can be used to create the right setting for power, amperage, and wire control. You always have 1 hand free to support the welding torch and guide it to the right position, since the consumable wire is automatically fed into the gun. This makes it quite handy to use the MAG welding procedure in a variety of welding positions.

Last but not least is the price of the shielding gas. Generally, CO2 is used for shielding in MAG welding, which is much cheaper than Argon or Helium. Even if you use a mixture of CO2 with argon, it will cost you less than using pure Argon.

Due to these special advantages, many welders prefer to use the MAG technique for welding.

Related Questions

What is meant by MAG welding?

MAG stands for Metal Active Gases. It is a type of Gas Metal Arc Welding (GMAW) where welders use a mixture of gases to shield the weld puddle and arc to create a higher quality weld.

A metal electrode is fed through the contact tip from a wire feeding spool gun while a shielding gas is fed through the welding torch in this process.

What is the difference between MIG and MAG welding?

In MIG welding, only inert gases or gas mixtures are used for shielding gas purposes. Commonly used inert gases include argon and helium.

In MAG welding, metal active gases are used for shielding the weld puddle. Commonly used gases include a mixture of argon, carbon dioxide, and oxygen.

Why CO2 is used in MAG welding?

Carbon Dioxide is one of the most reactive gases. It offers great metal penetration while providing adequate shielding for the arc. It is one of the few gases that can be used in MAG welding in its pure form without the addition of inert gas, making it very cheap as well.

What is the advantage of MIG welding?

MIG welding offers a much better quality finish than MAG welding. It is ideal for use in thin metal frame projects where you need to work on surface plating or delicate material.


About Pierre Young

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Hey, I'm Pierre Young a qualified AWS Certified Welder. I got into welding in 2009 as a side hustle. Ever since then, I've been doing all kinds of welds - both for business and pleasure. While immersing myself in this wonderful hobby, I've learned from hands-on experience what welding gear works and what doesn't. Welding Headquarters is the site where I share everything I've learned.

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