In the most general terms, welding is a method for joining two pieces of metal or plastic together. By fusing materials at the molecular level, welding creates a much stronger joint than merely bolting or riveting pieces together. This is why they use it to build bridges and oil derricks, manufacture everything from airplanes to electronics and even create fine jewelry.

If you’re thinking about learning how to weld, read this exhaustive guide to get an overview of the many types of welding and what their uses are. It should help you decide what kind of welding is right for your goals.

Welding actually encompasses many different techniques, equipment, and materials used for fusing metals and some plastics. There is no single, best way how to weld. Each type suites best for particular applications, so the variety of welding you learn should depend on the sorts of projects that interest you.

Hobart 500559 Handler 140 MIG Welder 115V
  • 5-position voltage control selector adds a smooth, stable arc at all welding thicknesses
  • Welds 24 gauge up to 1/4 in mild steel; Weldable Materials: Steel, Stainless Steel and Aluminum
  • Welding Processes: MIG(GMAW), Flux Cored(FCAW)
Lincoln Electric Square Wave TIG 200 TIG Welder, K5126-1
  • Advanced features yet easy to use
  • A great TIG machine for aluminum
  • TIG and stick from one power source

How to Weld using Fusion Welding?

Fusion welding is an umbrella term for any type of welding in which the pieces you want to join, called the workpieces, melt together. It usually involves adding a filler material at the site where the workpieces join to strengthen the weld, but not always. Because the workpieces actually melt together during the welding process, fusion welding creates some of the strongest bonds. The weld is as strong as the workpieces themselves. It’s also necessary for the workpieces to have the same base metal in order for them to melt together and have it result in a strong weld.

How to weld using Fusion welding includes all of the most commonly used welding processes. It also offers the most career opportunities for those interested in a welding career. There are many different types of fusion welding, but they all fall into three general categories: arc welding, gas welding, and power-beam processes.

Types of Fusion Welding

​​Arc Welding

Arc welding uses an electrical arc to provide the heat that melts the workpieces. Electricity flows through an electrode and arcs to weld the metal pieces. The electrode can either be a wire or rod that only conducts electricity, or it can be a wire or rod that melts and provides the filler metal to help bond the workpieces. An electrode that melts and includes filler is consumable. The electrical arc is around 6,500 degrees Fahrenheit at the tip. As the electrode moves along to the joined seam, the weld cools behind it, forming a bond.

Gas-Shielded Arc Welding vs. Submerged Welding

If you want to create a good, strong bond, it’s important to protect the melted part of the weld, called the melt pool, from the atmosphere. Oxygen and water vapor in the air react with the hot metal to form oxides and nitrides, which weaken the weld. As a way to shield the weld, most arc welding includes a gas or vapor cloud around the arc and melt pool. This is accomplished by heating another material, called flux, which produces a gas when it’s heated. When the base metal contains iron, the gas shield is carbon dioxide, hydrogen, oxygen or nitrogen. Argon or helium are generally used with other metals.

Submerged Arc Welding

Another method for protecting the arc and melt pool during the welding process is by ‘submerging’ them in flux, which means covering the arc and melt pool with a layer of small particles made up of silica, lime, calcium fluoride and other materials. Submerged welding only works when the weld needs to be done on a flat surface, so its applications are limited. However, it’s a preferred method in automated welding on long, straight welds because it’s fast and forms a strong joint.

Basic Arc Welding Equipment

Every type of arc welding requires four essential pieces of equipment: a power source, cables, an electrode holder and an electrode. The power source provides the electricity that ultimately creates the heating arc. The cables carry electricity from the power source, through the electrode holder to the electrode, and then from the workpiece back to the power source. The electrode holder generally takes the form of a clamp or gun, and electrodes can be consumable or non-consumable. The consumable electrodes are often coated with flux to create a gas shield.

Types of Arc Welding

​There are different types of arc welding, and each is good for various applications. Understanding the advantages and disadvantages of each process makes it easier to understand why they’re better for some projects and not others.

Flux-Cored Arc Welding

In flux-cored arc welding or FCAW, the electrode holder is generally a gun welder with a motor that continuously feeds the electrode through. The electrode itself is a tube filled with flux which creates the shield as it melts. The metal tube around the flux core melts to provide the filler metal.

Uses

FCAW can be used no matter what position the workpieces are in and it has a high deposition rate so that welds can be done quickly. Most importantly, some types of flux-cored electrodes use a flux that produces slag instead of gas, so the shield can’t blow away. This makes it ideal for outside work, so this type of welding is popular on construction sites and in ship-building. The electrode wire is more expensive than for other types of arc welding, as is the equipment. Slag-producing electrodes also leave a coating over the weld that needs to be chipped off once it cools.

​MIG Welding and MAG Welding

​Like flux-cored arc welding, both MIG and MAG welding use a gun-type electrode holder that feeds the wire electrode through. The difference is that the gas shield also gets fed through the welding gun rather than being produced by flux inside the electrode being heated. MIG stands for metal inert gas, and MAG stands for metal active gas, which indicates the distinguishing characteristic of these two types of arc welding. In MIG welding, the shielding gas is a mix of inert gasses, like argon and helium. In MAG, the shielding gas is generally a mixture of carbon dioxide, argon, and oxygen.

Uses

​The most commonly used welding process and the easiest to learn is probably MIG and MAG welding. You’ll find them applied in the automotive, sheet metal and shipbuilding industries, in the production of pipelines and pressurized vessels and in home improvement. MIG welding is usually used on metals without iron in them, such as aluminum, while MAG pertains to iron-containing metals.

​TIG Welding

Also known as gas tungsten arc welding, or GTAW is TIG welding or tungsten inert gas welding. The welding gun provides the gas shield, usually argon, much like in MIG and MAG welding. However, the tungsten electrode is non-consumable. You can use a filler in TIG welding, but the rod must be fed into the weld manually.

The purpose of TIG welding is primarily to weld thin, light metals, such as copper, magnesium alloys and aluminum, from 0.5 to 3 millimeters thick. It isn’t as fast as some other types of welding, but it can weld any joint in any position.    

​Plasma Arc Welding

​The main difference between TIG welding and plasma arc welding is that the shape of the arc is different. In TIG welding, the arc is cone-shaped, so the length of the arc changes the characteristics of the weld. If the tip of the electrode is close to the workpieces, the arc length is short, making the weld relatively narrow and deep. If the tip is held further away the arc length is long, and the arc is relatively wide, creating a flatter, shallower weld. That means making a consistent weld depends on the skill of the welder.

Uses of Plasma Arc Welding

In plasma welding, a plasma gas is used to shield the arc, which makes the arc more straight and narrow. That means the weld has a consistent size, even if the welder moves the electrode tip closer or further away from the workpieces. It’s also very fast and doesn’t cause much deformation to the workpieces. It’s used on many of the same materials as TIG welding, except for magnesium alloys, although it can be used on materials both thinner and thicker than TIG welding. For example, its uses include welding ultra-thin materials in the space industry and the automated welding of stainless steel pipes.

​Oxy-Fuel Gas Welding

Gas welding differs fundamentally from arc welding in that it doesn’t use electricity to produce heat. Instead, burning gas generates the heat that melts the workpiece base metal and filler, that gets added manually. The gas is usually acetylene in oxygen, and at around 5,600 Fahrenheit, it burns at a lower temperature than an arc welder. This lower temperature makes it good for metals that tend to crack, like cast iron. The gas flame provides the shield that protects the weld from reacting with atmosphere, so they require no flux.

Although gas welding isn’t as common as it once was, it has the advantage of being versatile and using the relatively cheap equipment. It’s good for welding pipes, making repairs and welding any materials between 0.5 and 6 millimeters. They also use the gas torch for heating and cutting metal.

Basic Gas Welding Equipment

Gas welding requires a tank of oxygen and a tank of acetylene, pressure regulators, hoses, flashback arrestors, a welding torch and if desired, uncoated rods to use as filler. Safety should be a primary focus when gas welding. The oxygen and acetylene tanks should be stored apart from each other in a well-ventilated area. The pressure regulators keep the flow of gas stable, and the hoses carry the gasses to the welding torch. Flashback arrestors are another safety feature that prevents the flame from moving back up the hose and causing an explosion. The welding torch provides the flame for welding.

​Power-Beam Process Welding

For the last 30 years, the newest developments in welding are in power-beam processes. These use other energy sources to create heat for fusion, specifically lasers, and electron beams. Power-beam processes have several advantages over traditional fusion welding methods; they are much faster, create a stronger joint and can produce very narrow deep welds. However, power-beam processes require a nearly perfect fit between the two workpieces. The shrinkage of material after cooling can also cause cracking and deformation.

Power-beam processes are increasingly the preferred welding method in the aerospace and automotive industries, shipyards, the oil, and gas industry and in the manufacture of medical devices.

Types of Power-Beam Process Welding

Power-beam processes include laser and electron beam welding. Equipment for these processes can be fairly complex. Because of this complexity and the nature of power-beam processes, they are usually performed automatically for industrial applications.

​Laser Welding

​Laser beam welding, or LW welding, uses a laser to heat metal and plastics. The laser is a beam of excited photons, or light, produced by exciting either solid materials or gasses. They call lasers that use solid materials as solid-state lasers. The most commonly used solid-state laser in welding is the Nd: YAG laser. They also use Laser welding in the automotive industry, medical device manufacturing, and jewelry making.

​Electron Beam Welding

​Electron beam welding, or EB welding, uses a stream of electrons to heat materials. As the cathode emits electrons, a strong electrical field accelerates them.  The electrons are moving so fast when they hit the base metal that the kinetic energy, or energy of the movement, is changed into heat energy. EB welding is most useful in the construction of components that require high-strength bonding. Aerospace gears, combustion chamber covers for gas turbines and semiconductor fabrication equipment are just a few of the applications for EB welding.

How to Weld Using Pressure Welding?

​How to weld using Pressure welding encompasses any welding methods that join materials by pressing or working them together. In some types of pressure welding, they heated the workpieces before being pressed together, but not in every type. They use a filler material at the weld site to strengthen the bond, but this does not occur in every type of pressure welding.

How to Weld Using Resistance Welding?

​Where two metal pieces touch, it creates resistance to an electrical current. By running a current through this resistance, enough heat is generated to melt the base material so it can be forced together. Resistance welding has the advantage of being fast and not requiring any filler material. On the other hand, it’s not very flexible. Each type of resistance welding uses specialized equipment that they only use to perform one task. It is usually automated.

How to weld using Resistance welding is most common in the automotive industry, in the manufacturing of shopping carts, stainless steel sinks and chains, and to make furniture parts, to name a few.

Types of resistance welding include the following:

  • ​Spot Welding
  • ​Projection Welding
  • ​Butt Welding
  • ​Flash Welding

Other Types of Pressure Welding

Other types of pressure welding include friction welding and ultrasonic welding. In friction welding, one part rotates against the other. The heat generated by the friction and deformation of the materials creates the weld. Ultrasonic welding uses high-frequency vibration and pressure to fuse materials. Ultrasonic welding is the most common type of plastic welding. It is prevalent in industries as diverse as automobile manufacturing, medical device manufacturing, food packaging, and electronics.

How to Weld Using Soldering and Brazing?

​They use Soldering and Brazing to join different types of metals together, even if they have very different melting points. This occurs by heating a filler metal with a lower melting point than the base metals of the workpieces. The molten filler metal fills the joint between the two solid workpieces and diffuses into each, creating an alloy in the narrow zones alongside the joint. This effectively joins the parts together, forming a strong bond between them. The gap between the two pieces shouldn’t be any wider than 0.5 millimeters.

Working temperature is what differentiates soldering from brazing. Soldering, or soft soldering, takes place at temperatures below 842 Fahrenheit, while brazing, sometimes called hard soldering, is utilized when temperatures over 842 Fahrenheit. The necessary temperature depends on the materials you want to join and the melting temperature of the fill required to join them.

Applications

Soldering and brazing have a wide variety of applications, such as with aluminum and aluminum alloys, copper and copper alloys, brass, silver and more. They’re critical in the manufacturing of circuit boards for electronics, making components for appliances like refrigerators and air conditioners and common in jewelry making.

​Ultimate Guide

If you’re considering learning how to weld, you should think about what your goals are and what type of projects interest you. Whether you’re considering a career in welding on how to weld or interested in developing a new hobby, there are many different types of welding on how to weld, each with different applications. If your goal is to earn the most money as a welder, look into underwater arc welding. If you’re a jewelry maker looking to expand your capabilities, soldering is the way to go. Now that you know all about welding on how to weld, you can make the right decision for you.

For instance,  if you would like to learn more on how to weld click here Learn How to and 22 Reasons to Go to Welding School.

Featured image: CC0 Public Domain jarmoluk via Pixabay

Hobart 500559 Handler 140 MIG Welder 115V
  • 5-position voltage control selector adds a smooth, stable arc at all welding thicknesses
  • Welds 24 gauge up to 1/4 in mild steel; Weldable Materials: Steel, Stainless Steel and Aluminum
  • Welding Processes: MIG(GMAW), Flux Cored(FCAW)
Lincoln Electric Square Wave TIG 200 TIG Welder, K5126-1
  • Advanced features yet easy to use
  • A great TIG machine for aluminum
  • TIG and stick from one power source

Become a Better Welder

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