Welding 101

Welding is the process of fusing two or more parts together by means of heat, pressure or both. As the parts cool, a joint is formed.

This fabrication process is usually used on metals and thermoplastics. Similar to that of soldering and brazing, welding requires a filler material or binder to join the two materials together.

There are 4 main types of welding; MIG, TIG, STICK and FLUX.

You'll see us mention these words/phrases throughout this guide. Here's what they mean:

Electrode: a conductor through which electricity enters or leaves an object, substance, or region

Weld pool: in metalworking, weld pool refers to the small workable portion of a weld where the base metal has reached its melting point and is ready to be infused with filler material.

Electric arc: an electrical breakdown of a gas that produces a prolonged electrical discharge. Electric arcs occur in nature in the form of lightning.

Weld bead: the metal deposited in the joint by the process and filler wire used

Filler wire: a metal added in the making of a joint. When heated, this metal liquifies and melts to flow into the space between two close fitting parts

MIG welding stands for Metal Insert Gas welding, and uses electricity to melt and join metal. This fast and easy process is perfect for beginners as it is by far the easiest method. MIG welding is quick to learn and you can cover several different types of welding using one machine.

Without getting too technical, Mig weld machines operate using a continuous wire electrode that is wound on a spool inside the Mig welding machine. Mig welding uses electrical energy to melt the electrode wire which is deposited to create a weld. Once the heat is removed, the weld pool cools and solidifies to form a new piece of fused metal. This is how you weld 1 piece of metal to another. In most cases, Mig welding requires a shielding gas to protect the weld pool from contamination.

By using electricity, an electrical arc (a short circuit) is created between an electrode wire.

Mig welding is one of the most common types of welding.

MAG welding is a Gas Metal Arc Welding (GMAW) process that uses heat created from a DC electric arc between a consumable metal electrode and a workpiece which melt together to create a weld pool that fuses to form a join.

Mag stands for Metal Active Gas.

What is the difference between MIG and MAG welding?

Mig and Mag welding are both GMAW processes. Shielding gas is needed in both cases, however the composition of shielding gas is different.

Mig welding uses inert gas, such as Argon as shielding gas. The shielding gas remains intact during welding (does not disintigrate) because of the pure inert gas. No external chemical element is induced into the weld bead. Mig welding cannot alter the chemical composition of the weld bead or its properties.

Mag welding uses a mixture of active gas, like oxygen or CO2, and inert gas as shielding gas. The shielding gas disintigrates during welding due to intense heat of the electric arc. Because of this, certain chemical elements, such as oxygen or carbon, are induced into the weld bead. Because of this process, Mag welding is capable of altering the chemical composion and properties of the weld bead.

Mig welding is preferred for joinging non-ferrous metals, like aluminium.

Mag welding is preferred for joning ferrous metals, like mild or stainless steel.

Tig welding stands for Tungsten inert gas welding and is a sub-type of GMAW that uses electricity to melt and join metal. Tig welding is suitable for welding many different types of metal.

Tig welding is a stable arc welding process that uses a non-consumable tungsten electrode and an inert gas in the welding arc to create high-quality welds. It joins pieces of metal together through a welding current.

Tig welding is typically used for its versatility, cleanliness and minimal finishing requirement, though it isn’t the easiest welding technique to learn or master.

Difference between Mig and Tig welding

Tig welding requires a separate filler material to be fed onto the weld with one hand while operating the torch with the other. With MIG welding, a wire electrode is continuously fed through the spool gun to create the weld.

Tig welding can be difficult for inexperienced users due to the multitasking required.

A Mig welder can weld thicker materials and faster. Tig welding works better with thinner metals and smaller projects.

Tig welding leaves a very clean and neat finish therefore is often used in structural or artistic applications.

Arc welding is the only welding technique that can be safely done underwater. Arc welding uses an electric arc to create heat to melt and join metals.

It depends on the grade of cast iron.

Cast iron comes in different grades; grey iron, white iron, ductile iron and malleable iron. All cast iron can be welded apart from white iron. Though its worth noting that cast iron is much more difficult to weld than carbon steel.

If you are looking to weld cast iron, the best way to do so is Arc welding, provided the correct welding rods are used.

Inverter welders are designed for voltage regulation. They convert AC power supply into a lower usable DC voltage output.

Inverter welders are much more energy-efficient than traditional standard transformers. They are a perfect replacement for conventional welders when it comes to generating heat and consuming energy. In fact, they can output the same amount of energy while requiring up to 30% less input power.

Always keep a clean and tidy work area. Dirt, grease and oil can enter the weld pool if not, leading to contamination which may result in poor welding results.

Protective equipment is essential.

Always wear a welding helmet, and the best you can afford at that. Welding can damage your eyes if not. We stock a range of welding helmets at Toolstop.

Here's a look at some of our favourite welders and welding tools we have to offer...