Arc Welding Equipment: Basics to Get Started

Arc welding equipment mainly consists of a welding machine, a power source, a gas setup, electrodes, an electrode holder, and welding cables. The equipment categories you need are the same whether you’re going for MIG, TIG, or stick welding.

The type of welding machine, power supply, and electrodes will vary according to the type of welding you want to work on. Knowing each category and what goes into it is essential if you want to practice different welding styles.

Even if you prefer stick welding or MIG welding, it pays to be able to work with other equipment or at least have a basic understanding of it. So let’s go over arc welding basics before diving into what you need to start.

How Does Arc Welding Work?

With the dawn and expansion of electricity use in the 19th century, people quickly learned that a high-enough electric current produces a lot of heat. This heat can be used to melt metal. The molten metal can, in turn, be used to join two pieces of metal when cooled down.

Arc welding is a process in which an electric arc is created between the base metal and an electrode to melt either or both to join two pieces of metal together. 

A noble gas like argon or helium is used as a “shield” from atmospheric gases, like oxygen and water vapor as they can cause oxidation of the base metal. This oxidation makes the welding job weaker, less stable, and more prone to failure.

That means you need the following: 

1. A welding machine 
2. A power supply to run the welding machine
3. A noble gas setup to shield the operation
4. An electrode to complete the arc
5. A holder for the electrode
6. Cables

#1: The Welding Machine

Welding machines, also known as welders, provide the heat needed to melt the metal. You can find many types of welders, depending on the welding type you intend to do. The manual types include:

• Shielded Metal Arc Welding (Stick) Machines
• Flux Core Arc Welding Machines
• MIG (Metal Inert Gas) Welding Machines
• TIG (Tungsten Inert Gas) Welding Machines
• Multi-Purpose Welding Machines

The main design of the welding machine is pretty similar among the different types. The main differences are in the current the machine utilizes and the type of electrode you can use.

This depends on the power supply to which the welding machine is connected. These come in two categories:

• Constant Current, abbreviated as CC
• Constant Voltage, abbreviated as CV

Here’s how each of them works:

Constant Current 

A constant current (CC) power supply controls the current output even when the voltage running through it varies. Voltage changes are directly related to the arc length, so the shorter the arc, the higher the voltage.

Without a stabilizing action from the power supply, the heat produced from the electric current can vary greatly. This is a huge problem if you’re working manually, like in stick or TIG welding machines, because hands aren’t steady enough to maintain a constant arc length.

Constant Voltage

Constant voltage (CV) power supplies depend on the relative constancy of the arc length. When the arc length is constant, this stabilizes the voltage and produces a constant current.

Of course, manual welding jobs require always changing the arc length depending on the space between the electrode and the base metal. That’s why CV power supplies are mainly used with automated welding machines.

Here is my recommendations for the best welding machines for beginners:

#2: Power Source

A welding power supply is the source of the electric current that runs the welding machine. As mentioned above, any manual welder will utilize a constant current (CC) power supply. But what about the polarity of that constant current?

Polarity is the positive or negative charge on either side of the electric circuit. This charge is constant when dealing with direct current (DC), like a car battery. 

On the other hand, if your power supply runs on alternating current (AC), the charge cycles about 60 times in one second (aka a frequency of 60Hz) between the base metal and the electrode. 

This makes a difference in some types of welding, like stick or MIG welding, which have to work with DC power supplies to maintain welding quality. However, if you’re using a non-consumable electrode, like in TIG welding as we’ll explain below, you can use AC just fine.

AC power supplies are cheaper than AC/DC, but TIG welding equipment can be expensive. Getting an AC/DC power supply makes more sense when purchasing your equipment to work on stick or MIG welding projects.

#3: Gas Setup

In MIG or TIG welding, you need a constant stream of inert gas to shield your weld from atmospheric gases, like oxygen, nitrogen, or water vapor, that can cause oxidation and weld failure. 

The inert gases you can use are:

• Argon
• Helium
• CO₂

You can get cylinders of each gas in its pure form or, more commonly, cylinders of gas mixtures. That’s mainly to cut the cost of the weld, since pure argon or helium is much more expensive than CO₂.

Remember that welding aluminum will most likely require pure argon or helium. That’s because aluminum is very reactive and easily forms an oxide layer that can hinder proper welding if it’s not shielded enough.

Aside from the cylinder, you’ll need a regulator known as a flowmeter. This measures the gas flow so you can gauge how much you’re using.

#4: Electrodes

An electrode is the component of the welding circuit that carries the opposing charge to the base metal, completing the arc and heating the metal. There are two main categories of electrodes:

• Consumable electrodes
• Non-consumable electrodes

Let’s talk about each kind in a little more detail.

Consumable Electrodes

Consumable electrodes are made from metal with a low melting point, like nickel or mild steel. So, with the heat of the welding arc, they melt into the piece you’re working on.

They’re either bare or coated with a flux material. Bare electrodes have difficulty stabilizing the arc, so they’re rarely used.

Coated consumable electrodes are coated with either a light, medium, or heavy coat of flux material. The lighter the coat, the more precise and polished the piece looks. However, heavy coats stabilize the piece more and work for deeper welds of thicker metals.

Consumable electrodes can come as rods for stick welding, or as wires for MIG welding.

Non-consumable Electrodes

Non-consumable electrodes are made of materials with a high melting point that can withstand arc heat and remain intact. They’re either made of graphite carbon or tungsten.

Carbon has the advantage of welding non-ferrous metals pretty well. Of the two kinds, tungsten electrodes are easier to work with because they require much less current than graphite. They’re either made of pure tungsten, or with a small percentage of thorium or zirconium added.

You can tell whether or not the tungsten electrode is made of pure tungsten by the painted end of the electrode.

Green denotes a 99.5% tungsten electrode, slightly less precise and can get contaminated more easily.

Yellow is 1% thorium, and red is 2% thorium.

Brown, which is 0.3 to 0.5% zirconium. It works about as well as thorium electrodes, which is much better than pure tungsten electrodes.

#5: Electrode Holder

An electrode holder is exactly what it sounds like. A metal connector, either a clamp or a twist-grip connector, holds onto the electrode to connect it to the power supply.

Spring-loaded holders work great with consumable electrodes because they can grip them well. When the electrode is spent, the stub can be easily unloaded.

#6: Cables

You’ll need a cable to connect the electrode holder to the power supply and the base metal to ground it. These wires are made specifically from copper to endure high currents without failure.

Remember that they come in different gauges and at different quality points. You should go for something specially made for welding, as jumper cables cannot withstand the current of a welding machine’s power source.

Final Thoughts

Arc welding equipment falls under the same category for almost all types of manual welding. You should have a welding machine, a power supply, an inert gas setup, an electrode, an electrode holder, and cables to connect the circuit.

This setup generates enough heat to melt the base metal and/or the electrode to join two metal pieces together. 

The electric current coming from the power supply for most manual applications is a constant, direct current. This requires the power supply to be a constant current, AC/DC machine.

Lastly, you can either use consumable or non-consumable electrodes. Just make sure you’re using equipment that works with your electrode type.