Underwater Welding 101: Read this and be an expert in 5 minutes!

  • There are two types of underwater welding known as dry welding and wet welding
  • Dry welding takes place in extreme pressurised areas, such as under water, with the welders working from a pressurised chamber known as a habitat
  • Wet welding takes place in the water using waterproofed equipment to minimise the danger of electrocution
  • Electrocution is not the main danger to underwater welders, with more lives lost through diving incidents such as drowning, Delta P and underwater explosions
  • Death rates 40 times the US national average highlight the dangers of deep sea welding

underwater weldingThe idea of welding underwater seems bizarre in the extreme. From a very early age we are taught never to mix electricity and water. However, there are numerous occasions when pipelines and equipment submerged under water will need to be repaired but cannot be removed and taken to the surface. This has created a very lucrative but potentially very dangerous career although in reality the dangers are more associated with diving than they are with using electric equipment underwater.

Before we take a look at what you can expect from a career in underwater welding it would be helpful to dig a little deeper. Lets see exactly how underwater welding works.

How does underwater welding work?

The idea of using electricity when surrounded by water is extremely dangerous. However, modern day welding equipment has been developed that effectively eliminates the vast majority of the direct dangers. There are two different types of underwater welding which are known as:

Dry welding

Dry welding is commonly referred to as hyperbaric welding. It is performed in a variety of different sized enclosures known as “habitats”. These are man-made chambers which are lowered into the water and provide a continuous stream of air flowing through the working environment. The airflow is achieved using pipes which pump air from the surface through the chamber wall/ceiling. At the same time they use fans to remove the build-up of potentially toxic fumes. This constant airflow creates an environment in which a safe mix of air and other gases is introduced. The pressure in the chamber is set at a slightly higher level than the surface which helps to enhance the airflow.

All welding workshops contain a ventilation system which helps to avoid the buildup of potentially dangerous gases which can lead to explosions. If you can imagine, the dangers are magnified somewhat when working in habitats under the surface. The dry welding process in a habitat is exactly the same as one you would follow in a traditional environment. A dry weld habitat can vary in size from a simple cover for a welding electrode to one which can accommodate three welders at the same time. We will now take a look at wet welding which is often significantly more cost-effective than the use of what can be expensive habitats.

Wet welding

The first thing to mention with wet welding is the fact that all pieces of machinery are fully insulated and divers wear the same type of protective material you would use to avoid electric shocks while working on the surface. The way in which the machinery is shielded from the water is simple but extremely effective which we will try to explain in layman’s terms.

The process used is often referred to as shielded metal arc welding or stick welding and involves three main types of equipment:

  • Welding machine
  • Electrode holder (referred to as a stinger)
  • Electrode

The power supply used in the wet welding process is direct current only and there is a “knife switch” which ensures that the power is only supplied when required. This allows the wet welder to change electrodes as and when required without the danger of being electrocuted. We will now take a look at the actual process of welding underwater and how electrocution risks are minimised.

Heat movement

When the button is pressed on an underwater welding device it creates a positive current on the electrode which is drawn towards the negatively charged work area. The negative charge from the work area is itself drawn towards the positive charge on the electrode. As these charges collide they create an intense heat which can reach in excess of 5000°C creating the heat which turns the metal into a more malleable material – allowing the weld to be completed. Aside from waterproofing on the exterior of the welder how is the electrode protected in the water?

As the electrode heats up to in excess of 5000°C this converts the flux on the outside of the electrode into a gas. This creates a bubble around the weld which also offers a degree of protection to the electrode. This also allows the weld area to remain dry and as the welding machine is moved along the metal this leaves behind a metal liquid known as “slag”. Often thought of as a waste product, this molten metal covers the weld seam allowing it to cool under more favourable conditions. As the slag cools immediately this layer on top of the weld seam is invaluable and can be manually removed at a later date if required.

It is no surprise to learn that the welding process creates a mass of air bubbles which are drawn to the surface thereby reducing visibility and potentially impacting the effectiveness of the weld electrode. An experienced underwater welder will know how to position the welding machine in a fashion which minimises visibility issues.

Glossary of terms associated with underwater welding

  • Hyperbaric welding – the process of welding at extreme pressures (high and low)
  • Dry welding – the process of welding within an artificial chamber known as a habitat
  • Wet welding – the process of welding underwater with no pressurised protection
  • Electrode – this creates the positive charge which reacts with the work surface’s negative charge. Producing heat in excess of 5000°C
  • Flux – the flux surrounds the electrode offering additional protection. The extreme heat prompts a chemical reaction creating a gas bubble surrounding the weld area
  • Slag – this is the molten metal left behind as the weld stick is moved, covering the weld seam thereby allowing it to cool in a controlled manner
  • Arc welding – the process by which an electrode reacts with the work surface to create an arc -like area of intense heat. This turns the metal into a liquid form allowing the weld to be completed
  • Delta P – otherwise known as differential pressure this can prove fatal when two bodies of water intersect at different levels. If repairing, for example, damaged pipes, when the blockage is removed the water on each side will very quickly level. Potentially creating a release of enormous pressure.

underwater weldingPursuing a career in underwater welding

Anyone looking to pursue a career in underwater welding will have to be a competent diver as well as a competent welder. There are various underwater welding schools across the globe offering underwater welding courses. Some of the more specialist courses can take as little as six months. However, a commercial diving and general welding course can sometimes take between two and five years. It will obviously depend on the individuals experience, skills and commitment as well as the quality of the underwater welding school.

Underwater Welding FAQ

How much does an underwater welder make an hour?

It will obviously depend upon the type of work, location, the number of projects and availability. However, a qualified underwater welder can expect to make upwards of $26 an hour. It is difficult to put an exact figure on the hourly rate of an underwater welder as many are paid per project. This can be tens of thousands of dollars but they spend the rest of the year looking for additional work. Diving experience will also have a major impact upon the level of remuneration for an individual. There are many welders in the world but few who can bring together diving experience and welding skills.

How dangerous is underwater welding?

It will surprise many people to learn that the risk of electrocution does not head the list of dangers for underwater welders. As we touched on above, all of the machinery used is waterproofed, a knife switch ensures power is only used when required and all divers wear protective clothing. It is also worth noting that the welding arc creates a path of least resistance between the electrode and the working area thereby reducing the chances of being electrocuted. So what are the main dangers?

The main dangers of welding underwater include decompression sickness, hypothermia, drowning, and explosions and, perhaps most important of all, Delta P. Delta P is a process by which two sides of connected water will automatically rebalance when any blockages are removed. When you bear in mind some of the depths at which deep sea welding can occur, these pressures can be enormous. They have been known to drag divers into pipes, suck in arms and legs and if the injuries don’t get them, the lack of oxygen will. When welding underwater there will usually be a team in constant communication with the underwater welders. They will be ready to enter the water to assist when required.

How much money does an underwater welder make a year?

It is almost impossible to calculate an average annual salary for an underwater welder but figures provided by the https://waterwelders.com/ website give an interesting insight. According to the website, the average underwater welding salary is just under $54,000 a year. The range can be anywhere between $25,000 up to $80,000 and beyond for specialist projects. The top 10% of underwater welders in the world will make nearly $84,000 per year while the bottom 10% can pull in up to $30,700 a year. As you would expect, in such a potentially dangerous field of work, employers will pay the highest rates for those underwater welders with the most experience.

What is the average life expectancy of an underwater welder?

Predicting the life expectancy of an underwater welder is not a precise science. There have been a number of studies over the years looking at this subject. However, it might surprise many to learn that a study by the US Defence Technical Information Center cast a very interesting light on life expectancy. While many are overly concern about the threat of electrocution when using welding equipment underwater, there is only one officially reported death from electrocution which occurred back in 1943. The individual involved was alleged to have carried out underwater welding in 10 feet of water wearing protective clothing except he was barefoot.

An article by the US Center for Disease Control and Prevention provided statistics from which it was possible to calculate the underwater welding death rate. It found that the rate of death was more than 40 times the American national average – 11 underwater welders dying each year. A further study between 2002 and 2014, although not carried out on a scientific basis, used data from the Divers Association in America. The figures indicated welder divers were dying between the age of 35 and 40. With many only entering diving school at 20 years of age, the average working life expectancy was between 10 and 15 years. While it is difficult to challenge or confirm these figures, this is the only life expectancy survey carried out into the deep sea welding industry.


Underwater welding is one of the most specialised jobs in the world. It is also one of the most dangerous for reasons which are not immediately obvious. Many people automatically assume that electrocution is the main danger. In reality it is possible to minimise the risk of electrocution to near zero if all safety precautions are respected. The main dangers come from different aspects of diving from decompression sickness to explosions, from Delta P to drowning.

A non-scientific study into the life expectancy of underwater welders was alarming to say the least. It suggested a death rate of more than 40 times the US average. Those employing the skills of underwater welders will suggest they are well compensated with salaries ranging from $25,000 a year anyway up to $80,000 and beyond. Specialist projects will require experienced underwater welders who do not come cheaply.

For those looking at a career in underwater welding the best advice would be to perfect your diving skills. While also appreciating all of the safety precautions surrounding the use of welding equipment underwater. Some of the more experienced specialist underwater welders can earn six-figure salaries. However, for this type of income there will be a significant increase in the risk factor.



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