How to get started with MIG-MAG welding

Arc welding is the most popular type of welding among DIYers mainly thanks to the kind of versatility it offers. In fact, most ferrous metals can be welded using this technique.

What is the Difference Between MIG and MAG welding?

• Metal inert gas (MIG) welding: a continuous solid wire electrode is used to produce the weld under the protection of an inert gas such as argon or helium.

• Metal active gas (MAG) welding: a continuous solid wire electrode is used to produce the weld under the protection of an active gas such as an argon/CO2 or argon/oxygen mix.

• Gasless MIG welding: welds are produced using a flux cored welding wire.

Once you've really got the hang of manual arc welding, it's only naturally to want to explore new horizons. This usually means moving on to so-called semi-automatic welding. MIG-MAG welding is the most commonly used welding process among both professionals and hobbyists – and with good reason. Let's take a look at the various equipment used for this type of welding and try to draw up a reasonable budget to get you started.

While manual metal arc (MMA) welding is somewhat limiting when it comes to thin materials, MIG-MAG welding can be used to tackle sheet metals such as bodywork panels. That's why most auto mechanic repairs rely on this type of welding. In fact, all types of metalworkers, from welders to blacksmiths, use MIG-MAG welding to construct all manners of structures and vessels.

In terms of performance, a machine-fed wire rod system translates into increased productivity. What's more, the absence of a flux coating makes welds easier to clean. It's even possible to use welding wire up to 3mm to assemble large components.

Metals like aluminium and stainless steel can also be welded using this process provided you use the right wire and gas. However, it's worth noting that shielding gas – whether you use neutral or active gas – will mean a fairly significant additional expense. Two types of wire can be used in MIG welding:

• solid bare wire used with gas (for indoor welding only);

• flux core wire with a flux compound inside the electrode for gasless welding outdoors.

Welding machine

You might be tempted to invest in a welding station that offers both solid wire MIG welding and flux cored arc welding and this is usually a good idea. While it is possible to find low-end welding machines designed exclusively for gasless welding bear in mind that flux cored arc welding does require skill and the welds produced will almost always be inferior to those crafted with MIG welding.

What's more, things can get tricky if you plan to carry out auto body repairs which require a greater degree of precision. Flux core wire usually starts at 0.9mm in size (since the flux compound is contained within the welding wire) while solid wire can be as thin as 0.6mm.

If you are on a 230 V single-phase supply you can choose from a wide range of welders. Opt for mid-range to high-end models based on how often you plan to use the welder and your budget. The most important criteria to bear in mind when choosing a model are power and duty cycle.

Quick note: aluminium welding calls for a powerful welder with a water-cooled torch – you need to be absolutely confident when choosing a welder for this type of application.

Duty cycles

The duty cycle of a welding machine refers to how long the welder can operate safely. A minimum duty cycle of 60 to 70% is recommended for a welding machine supplied by single-phase power. To translate, this means that for 10 minutes of operation at 100A, you will have 6/7 minutes of welding and 3/4 minutes of cooling with a well-ventilated welding station.

Welding torches

Welding torches are designed to cool using air or water. The torch provided with the welding machine can be changed. You can opt to replace the original torch with a higher quality model as long as you ensure it is compatible with the machine and matches your needs. Doing so will only help to enhance your comfort when welding.

Replacement welding torch parts

Don't forget to stock up on spares for any welding torch components designed as wear parts.

Welding wire

Welding wire should always be chosen to match the task at hand. You might want to store a range of different sizes for various welding tasks. Be sure to check that the size of the wire matches the capacity of the feed roller.

Welding gas

Welding gas comes in cartridges, bottles (60 or 120 litres) or even in disposable gas cylinders of 1 to 10 m3. The welder is linked to the gas via a gas regulator. For general use, an argon CO2 mix can be a good option. It is good practice to double check that your bottles are firmly closed when you have finished using them.

Welding helmets

A huge range of LCD welding helmets is now available. Be sure to look for an auto-darkening feature when purchasing.

MIG welding pliers

Welding pliers are multi-purpose tools designed for tasks like cutting welding wire and removing and installing nozzles and contact tips.

Anti-spatter spray

Spraying an anti-splatter spray around your welds will prevent spatter formation which can save you a lot of time.

Welding apron and gloves

When it comes to personal protective equipment (PPE), leather will usually be the safest option. A welding apron and welding gloves must be worn at all times.

Angle grinder

It is essential to have an 115mm angle grinder on hand to fix any mistakes. That said, there's no need to get the fanciest piece of kit out there. To make your choice, think about how often you plan to use the tool.

If you are planning to set up a little metalworking corner in the workshop or garage, ensure that the space is well-ventilated and kit it out with the following:

• a metal workbench or, failing that, a wood workbench with a strong sheet metal top. Bear in mind that the workbench can never be too big. If you have the space, go for a large workbench.

• a shelf where your welding machine and angle grinder can be stored within easy reach;

• a tool storage system or toolbox with essential tools like a hammer, clamps, spanners, a hacksaw, and so on.

• a metal vice with or without a pivoting base;

• a pair or several trestles for welding larger items.

Having a dedicated welding area is really handy as you can simply bring anything you want to weld to your welding station rather than having to constantly move around your equipment. Keeping your workshop tidy and clean will reduce the risk of accidents.

The following personal protective equipment (PPE) is essential for any welder:

• safety shoes;

• welding gloves;

• safety goggles

• welding helmet;

• workwear;

• welder's apron.

PPE will make carrying out your work much safer.

Set up a fire extinguisher in the workshop and make sure you have a bucket of cold water nearby to cool your welds if necessary.