What is Underwater Welding and How Does it Work?

What is Underwater Welding?

Underwater welding, also known as hyperbaric welding, involves welding at elevated pressures.

The welding can either take place in the water itself (known as wet welding) or in a dry, pressurized enclosure (known as dry welding), with steel being the most commonly welded material.

The term ‘hyperbaric welding’ is usually used when referring to dry welding and ‘underwater welding’ for wet environments.

Hyperbaric welding can either take place wet in the water itself or dry inside a specially constructed positive pressure enclosure and hence a dry environment.

It is predominantly referred to as “hyperbaric welding” when used in a dry environment, and “underwater welding” when in a wet environment. The applications of hyperbaric welding are diverse—it is often used to repair ships, offshore oil platforms, and pipelines. Steel is the most common material welded.

Dry welding is used in preference to wet underwater welding when high-quality welds are required because of the increased control over conditions that can be maintained, such as through the application of prior and post-weld heat treatments.

This improved environmental control leads directly to improved process performance and a generally much higher quality weld than a comparative wet weld. Thus, when a very high-quality weld is required, dry hyperbaric welding is normally utilized.

Research into using dry hyperbaric welding at depths of up to 1,000 meters (3,300 ft) is ongoing. In general, assuring the integrity of underwater welds can be difficult (but is possible using various nondestructive testing applications), especially for wet underwater welds, because defects are difficult to detect if the defects are beneath the surface of the weld.

Welding underwater can be achieved by two methods: wet welding & dry welding.

Wet Welding

Wet welding entails the diver performing the weld directly in the water. It involves using a specially designed welding rod and employs a similar process used in ordinary welding.

Here are the advantages to wet welding:

  • Cheap and fast
  • High tensile strength
  • Ease of access to weld spot
  • No habitat
  • No construction

Dry Welding/Hyperbaric Welding

Another method of welding underwater is hyperbaric welding or dry welding. Hyperbaric welding is the process by which a chamber is sealed around the structure that is to be welded. It is then filled with a gas (typically a mixture of helium and oxygen, or argon), which then forces the water outside of the hyperbaric sphere. This allows for a dry environment in which to perform the weld.

Here are some advantages of dry welding:

  • Welder/diver safety
  • Higher weld quality
  • Surface monitoring
  • Non-destructive testing

How Does Underwater Welding Work?

There are surprisingly a number of ways that welder divers do it. After being given an assignment, project managers and expert welder divers choose between several types of underwater welding that will best suit their needs. Find out more about their specific welding processes below.


1. Wet Welding

Most of the time, divers use Shielded Metal Arc Welding (SMAW) or “stick welding” as it is the most cost-effective and versatile method for wet welding. With this method, they produce an electric arc between their electrode and the infrastructure metals (like stainless steel and aluminum) that will be welded together.

It’s important that welder-divers keep their electrodes clean. Also, once they’ve reached the weld area, divers usually check the surroundings for any obstructions or safety hazards before performing the weld.

When the diver is ready, they start by placing their electrode on the target surface and signaling their team to flip the current on, generating 300 to 400 amps of electricity via direct current (DC).

As for how the diver doesn’t get electrocuted, the key is in the thick layer of gaseous bubbles that the flux (or external coating) of the electrode creates to cover the weld and shield the electricity from water, corrosive gasses, and other oxidizing compounds. The team also uses direct current (DC) as it is safer and more effective to use underwater than alternating current (AC).

Other common types of wet underwater welding methods include:

  • Flux-cored Arc Welding (FCAW)Makes use of a continuously fed filler metal or electrode to weld nickel-based alloys and cast-iron metals, among others.
  • Friction Welding (FW) – Uses high friction and heat instead of material melting to fuse metal or thermoplastics together.

2. Dry Welding

As previously mentioned, dry welding or habitat welding involves the use of a hyperbaric chamber while referring to the same basic welding process. After creating a seal around the structure that needs to be welded, connected hoses flush water out and replaces it with a mixture of gases, like helium and oxygen.

After pushing all the water out, the hyperbaric chamber will then be pressurized to the correct depth to avoid decompression sickness.

The technique that will be used will depend on the size of the chamber. Here are the four types of dry welding methods that welder-divers choose from:

  • Pressure Welding: Method used for working in a pressure vessel, which measures approximately one atmosphere unit of pressure (similar to sea-level pressure).
  • Habitat Welding: Welder-diver uses a small, room-sized chamber with the same pressure outside it (ambient pressure) at working depth. The chamber will displace the water into the surrounding body of water before the welder-diver enters.
  • Dry Chamber Welding: The welder diver enters the small chamber from underneath and gets covered only from the head down to the shoulders (with diving gear).
  • Dry Spot Welding: Technique used for chambers that are clear and about as small as a person’s head. It is placed on the weld site and the welder-diver will have to insert the electrode into the habitat, which will conveniently seal around it.

Shielded Metal Arc Welding (SMAW) and Flux-cored Arc Welding (FCAW) are also used during dry underwater welding, as well as the following common welds:

  • Gas Tungsten Arc Welding (GTAW): Also referred to as “TIG,” this welding process uses a non-consumable electrode made of tungsten. Heat will be applied, along with an electric arc, on stainless steel, aluminum, and other metals that need to be welded.
  • Gas Metal Arc Welding (GMAW): Also referred to as “MIG,” it is known for its various metal transfer methods. This method uses shielding gas that runs through the welding gun around the electrode to weld non-ferrous metals like aluminum.
  • Plasma Arc Welding (PAW): Also makes use of an electric arc, but the arc is constricted to produce a high arc (plasma) speed and intense heat for welding stainless steel, aluminum, and other metals.

For extensive deep underwater welds inside large hyperbaric chambers, welder divers usually work in pairs. Once the operators have lowered the chamber down to the weld site and filled it with gas, the welders will drop to the same depth (in a diving bell), swim into the chamber, and start the weld, often alternating between 6-hour to 8-hour shifts.

How Much is an Underwater Welding Salary?

Underwater welding takes very little time to learn, but years to master. Many underwater welders start their journey in diving school, intent on taking the plunge as quickly as possible.

According to commercial divers and global statistics, the average underwater welding salary is $53,990 annually and $25.96 per hour. However, most incomes float around $25,000 – $80,000. Diver welders in the top 10% make $83,730 while the bottom 10% pull in $30,700.

Diving experience is the biggest determiner of an underwater welder’s salary. Location comes in second.

Some commercial divers’ underwater welding salaries can hit up to $300,000+ annually.

Why the large pay range?

Most underwater welders receive pay by the hour or project. That means Joe Diver might make a hefty $30,000 in a few months with a big contract.

Then he spends another five months looking for his next gig.

Here are the primary factors that affect your diverse welder income:

  • Experience
  • Certification
  • Environment
  • Depth of Work
  • Dive Methods
  • Underwater Welding Equipment
  • Distance Offshore
  • Overtime
  • Other Factors

Every factor is part of a larger equation for increased pay, marketability, and career opportunity.

But to be passionate about this career, you need to know where it will take you.

1. Inland Income

Among the ponds, rivers, and lakes of your area, you’ll bring home a paycheck of about $40,000 – $80,000. Most of your work will focus on dock areas, bridges, dams, and small vessels.

Inland welder divers don’t get the money of their offshore counterparts.

But they have the luxury of a less rigorous schedule (40-hour weeks) and less traveling. Unfortunately, when it comes to welding, freshwater makes for a more unstable environment due to the lack of salt ions.

Plan on plenty of practice before striking your arc here.

2. Offshore Income

In the ocean, you’ll earn $40,000 – $100,000 or more each year.

Offshore underwater welders spend most of their time on oil rigs or large marine vessels like Navy ships. Their work schedule rarely lets up: It’s not uncommon to work 80 or more hours in a single week. However, due to your intense schedule, underwater welders will usually come back inland after a month out at sea.

Out in the ocean, underwater welders do a good deal of cleaning, pipe welding, and installation underneath major platforms. They must possess a good head for large machinery repair.

And if they have experience as a Diver Medical Technician – that’s a big bonus.

Unlike inland diving, offshore welder divers must come in for the winter. Oceans are simply too perilous: Tidal waves, hurricanes, and the like.

If you’re thinking ahead of time, you can find seasonal employment with a welding shop along the coasts and gain additional welding experience until spring comes.

The Money Tide

Either inland or offshore, underwater welders’ earning potential takes major leaps after the first 3 – 5 years in the industry.

These formative years shape…or break you. If you make it through, you’ll be the big fish: You’ll have a much higher chance of employment than the minnows – your less experienced colleagues.