Consumable electrodes

Consumable electrodes

As mentioned previously, stick welders usually use consumable welding rods, which will be referred to as stick electrodes here. These include light coated electrodes, as well as shielded arc or heavy coated electrodes.

As the name suggests, light coated electrodes have been finished with a thin coating which has been applied by techniques such as brushing and spraying. This is usually made up of a combination of several different materials, which are likely to be similar to the metals which you are welding together.

The arc streams created when using bare rods can be difficult to control, so if your job allows it then using a light coated electrode increases the arc stability. This will make your life quicker and easier.

However, that is not the only purpose behind having a light coating on the welding rods. Other benefits of using light coated electrodes are that impurities such as oxides and sulfur are reduced (or eliminated altogether), the drops of metal at the end of the welding rods are more regular in both size and frequency – meaning that your welds are smoother and neater – and they only produce a thin slag.

Shielded arc electrodes are similar to light coated electrodes, except for the fact that they have a heavy coating. Due to their tougher, heavy duty nature, they are better suited to applications such as welding cast iron.

There are three different types of coating applied to shielded arc electrodes, which each have different results during the welding process. Firstly, there are those with coatings containing cellulose, which uses a layer of gas to protect the weld zone; the coatings on the second type include mineral substances, which leave a layer of slag. The third type of coating on shielded arc electrodes is made up of a combination of cellulose and minerals.

Shielded arc electrodes which form a layer of gas are ideal because they act as a highly effective protective barrier, resulting in strong welds. The weld pool needs to be protected from certain atmospheric gasses (namely oxygen and nitrogen), which affect the welds and make them weak, porous and brittle. This protection can either be given through the use of a coated welding rod, or through a blast of gas which can separate the weld pool from the air (as described in the cellulose-coated shielded arc electrodes).

Just like light coated electrodes, shielded arc electrodes reduce oxides, sulfur and other impurities in the metal, leaving clean, smooth, regular welds. In addition, the weld arcs created by these welding rods are much easier to control than bare electrodes, which are prone to causing lots of spatter.

It might seem like a hassle if you opt for a mineral-coated shielded arc electrode which forms a slag, but, in fact, this slag can have a beneficial effect. It cools slowly – much slower than cellulose-coated shielded arc electrodes – which draws impurities up to the surface. As a result, you’ll end up with high-quality welds which are strong, durable and clean.