The Pros Guide To Underwater Welding

Our Everything You Need to Know Guide to Underwater Welding

If you said the words ‘underwater welding’ to most people, they would probably laugh. 

The idea of trying to use 300 to 400 amps of direct current while underwater naturally seems like a fast way to get to heaven for anyone who has heard the old adage, “water and electricity don’t mix”. 

Well, amazingly, underwater welding is a reality and is actually one of the most common jobs that commercial divers undertake.  

Let’s take the plunge to see how exactly underwater welding works and how it is literally keeping our world afloat. 

Underwater Welding Information: The Definition, The Process & Types 

What is underwater welding?

For those of you who are entirely new to commercial diving and are wondering what is underwater welding, let’s start by answering this question.

Simply, put, underwater welding is the process of using heat to join metals underwater. 

Roughly speaking, it involves the same equipment (though modified for underwater use), as you see used in your local garage. 

Indeed, it usually involves welding together two pieces of metal (welding techniques are now available for materials such as plastics)  in order to create a strong join. 

But are there that many things to weld underwater that can’t be lifted out of the water to repair?

The simple answer – yes. 

The vast majority of the world’s offshore structures are metal. Structures such as oil and gas platforms, as well as all the world’s shipping vessels, are made from metal. 

When they break, someone has to fix them, no matter where they are in the world’s oceans, lakes, or rivers. 

The price of wrenching out a 17,000-ton oil platform just to do some repairs would bankrupt even the largest company if they had to do it regularly. 

So it is up to commercial divers to dive in and get these jobs done using underwater welding.

The Different Types of Underwater Welding

Underwater welding is actually a type of Hyperbaric welding. 

Simply put, this is a term that refers to welding at elevated pressures, which in the case of underwater welding, are a result of the water pressure around the weld site. 

There are two main types of underwater welding – Dry and Wet welding

The industry commonly, and somewhat incorrectly, refers to dry welding as ‘hyperbaric welding’, while calling wet welding  ‘underwater welding’.

Dry welding is also known as ‘Habit welding’ on account of the dry environment that is constructed around the weld site.  

Dry welding is the safest but most costly type of underwater welding. 

Because this type of welding is done in dry conditions, the weld quality is regarded as being better than that of wet welding. 

However, companies are forced to balance the desired weld quality with the higher costs of creating a dry habitat around a weld site, since to undertake all underwater welding in this manner would be extremely costly and time-consuming. 

As such, dry welding is not considered a practical solution in the majority of cases. 

This means that divers must turn to wet welding. 

Wet welding, as the name suggests, involves literally welding in water. Naturally, this form of welding is more dangerous but is much faster and cheaper to undertake. 

Let’s look a little more closely at how these types of welding work.

How Does Underwater Welding Work?

The difference between dry and wet underwater welding is considerable. 

The most obvious difference is the environment in which they are undertaken. However, the differences go all the way down to welding technique and dive equipment needed when undertaking the weld. 

Before we get to the differences, let’s start with the similarities and the welding process.

Welding – The Process Explained

Arc welding is the process of using electricity to join metal. 

The science is relatively simple, a large current (either DC or AC) is used to create an electric arc, which is an electrical induced breakdown of a gas that creates an electrical discharge. 

This electrical arc is generated between the welder and the metal material. This arc is hot enough (over 5,000 degrees C in some cases)  that it melts the workpiece metal and electrode to form a molten pool of metal that covers the join. 

Depending on the surrounding heat, this molten metal quickly cools and forms a metal joint between the previously unjoined surfaces. 

There are numerous variations of arc welding, which include shielded metal arc welding (SMAW), gas tungsten arc welding (GTAW), plasma arc welding (PAW), and flux-cored arc welding (FCAW). However, the basic principle behind all these different approaches is the same. 

Shielded metal arc welding remains the most common type of arc welding, this is also true for the commercial diving industry. It produces strong joins and so is ideal for heavy metal. Other than steel and iron, arc welding of this nature can be used to join metals such as copper, nickel, and aluminum.

Dry Welding: Safe But Expensive

All of the above types of arc welding can be used in dry welding. This is another added bonus over wet welding, which as we shall see, only uses one of the above techniques. 

Before we get to the advantages of dry welding over wet welding, let’s take a look at how dry welding is done underwater. 

Dry welding would not be possible without some way to isolate the weld area. 

In order to do this, some form of dry environment or ‘habitat’ needs to be used. 

These habitats come in all shapes and sizes. In most cases, they are required to be big enough for a diver to get inside and to be able to work freely around the weld area. 

However, recent advances in technology have yielded much smaller dry welding apparatus that allows divers to operate the welder from outside a small dry habitat though which the welder is fixed.

One of the more ingenious dry habitats is used to weld underwater pipes. It is a large habitat that surrounds the raised pipe and is fixed into place by several large claws. Once connected to the pipe, the water is pumped out and the divers are free to climb inside to undertake their work in a dry environment. 

The beauty of this design is that it can easily be moved down the pipe so that the divers can weld large distances of pipe quickly. 

Due to the toxic gasses produced by arc welding, the habitat is required to have an ambient air pressure of around 0.5 to 0.7 bar, which is slightly above pressure outside. This means that there is a constant flow of air in and out of the chamber. 

This flow of air ensures that all toxic gases are quickly removed from the chamber and so do not pose a risk to the divers. 

At deeper depths, where divers would be in danger of developing nitrogen narcosis, a helium gas mix is used to keep the divers safe. Unlike nitrogen, helium has little to no narcotic effects on humans.  

Since a habitat is an expensive bit of kit, and the time it takes to set them up is far greater, costs naturally rise considerably for dry welding. However, since divers are able to work in a safe and dry environment, risks to divers, are dramatically reduced thanks to these habitats. 

Once the habitat is set up, the divers can enter a pressurized environment where they can take off their dive helmets and get unrestricted access to the weld area. 

From here on out, the welding process is the same as it is above the surface. The weld area will be cleaned before the divers will don their welding mask and start welding. 

Another huge advantage of dry welding is that the weld area can cool much slower than a wet weld. This has the effect of creating stronger bonds between the metals. Where post-weld heat treatments are required, dry habitat welding is the only option.

This is why dry welding is always used on the most important jobs such as those where toxic or explosive substances might be involved and the weld area will be under some stress. 

Once the diver is happy with the weld, they can undertake any required nondestructive testing in order to ensure the weld quality conforms with the required safety standards. 

After this, the process goes into reverse as the diver exits the chamber and it is depressurized and uncoupled, ready to be moved to the next welding area. 

Wet Welding: When Dry Welding Won’t Do

Now we get to the fun part. 

Wet welding uses shielded metal arc welding (SMAW) and involves welding in the water around the weld site. This is nearly always the type of weld used, though flux-cored welding and friction welding are also possible. 

While this might seem like utter insanity, the science that makes this approach possible is sound. 

As with dry welding, the diver will first clean the area around where the weld is to be made. This usually involves the use of an electronic device such as a grinder. In other cases, a simple wire brush will do. 

Once this is done, the diver will use a specialist underwater welder to undertake the weld. 

Working on the same principle as a normal welder, the main difference is that the electrode coolers are heavily insulated and designed for the strong cooling effect exhibited by the water environment. 

For this reason, a welder designed for underwater use cannot be used in a dry environment, otherwise, it will overheat. 

Since it is entirely underwater, AC current is avoided. Around 300 to 400 amps of direct current is used to power a waterproof electrode. 

The resulting electric arc heats the weld area where a gas bubble forms. This bubble, in effect, creates a dry habitat where the molten metal can create a join. 

The slag buildup that occurs on the weld surface helps to slow cooling of the weld, however, due to the surrounding water, wet welds cool much faster than dry welds. 

Wet welding has a number of advantages. 

Since a large sealed habitat is not required, divers can weld far greater areas than is possible with dry welding.

Naturally, if you can do more work per hour, this means that wet welding is better value for money and cheaper.

Unfortunately, wet welding has its drawbacks. To start with it exposes the diver to a far greater risk of electrocution, either by faulty equipment, diver error, or accident. 

There are no prizes for guessing the result of a diver being exposed to 300 amps of direct current while deep underwater. 

As we have already touched on, due to cooling, the weld quality and strength is not as good as with a dry weld, meaning wet welds are unsuitable for certain jobs. 

Decompression sickness, nitrogen narcotics, along with suspected longer-term cognitive problems, are all increased risks associated with wet welding.  

Finally, due to the large volume of bubbles given off by the welding process, divers’ visibility is often impaired, making it more difficult to ensure a good weld. 

How Dangerous Is Underwater Welding?

While the industry takes every precaution possible to try to ensure the safety of its divers, accidents do and will always happen. 

It is calculated that, on average, 11 underwater welders die each year.

While this figure is lower than those of deep-sea saturation divers, for example, the numbers are no less humbling. 

Commercial diving industry safety regulations are some of the most strict and comprehensive in the world. Companies are legally bound to do everything in their power to ensure the safety of their divers. 

This is also why the industry insists that all commercial divers be fully trained in whatever task they are being asked to perform.

Which Underwater Welding School To Pick?

Underwater welding training is a must if a diver is going to be able to weld well and safely. Throughout the world, there are scores of first-class underwater welding schools

Not only will this ensure that you don’t come up short for the right qualifications for that great underwater welding job, but it will also boost your earning potential too. 

Employers are constantly on the lookout for those A-star divers who can be relied upon to do a great job every time. 

In fact, diving folklore says that once you have made a good contact in the industry, it will be with you for life. 

Countless divers turned up on a short term contract and made a big enough splash that they have found themselves being headhunted by the very same employer. 

Without the best possible training, you won’t be able to do the best job possible.

How To Become An Underwater Welder

The idea of signing up for a commercial diving training course, breezing through training, then jumping on a helicopter to go earn some big bucks, might make a career as an underwater welder seem easy, but the reality is a little different. 

To start with, commercial diving requires a special kind of person. 

A typical commercial diver is an adventurous, level headed, well trained, and part nomad. Due to the work environment, there is little room for people who suffer from claustrophobia or anything like that. 

The path to becoming an underwater welder requires lots of dedication, hard work, and self-discipline. 

Provided that you have earned your high school diploma or G.E.D, and can pass a medical, you will be eligible to undertake a commercial diving course. A top-side welding qualification or experience is also a huge bonus. 

While it is possible to complete your commercial training in around 5 months, these courses usually rush students through the training and don’t pay enough attention to ensuring that they get all the training they need. 

A good diving school will require students to complete a 7-month long course, which means 8 to 10 hours a day, 5 days a week for the duration.

You will need to check to ensure that your course has an internationally recognized underwater welding certification, without it, you won’t get hired. 

Once you have all the underwater welding requirements, you can take the next step of finding a job. 

Keep in mind that your first few years are expected to be about you learning the ropes, building up experience, and making connections. 

If you keep your head down and do a great job, in no time you will be earning the big bucks.

Underwater Welding Jobs

Underwater welding companies are crying out for good underwater welders. 

Thanks to the enormous amount of work in the Gulf of Mexico, divers are in hot demand right here in the United States. 

There are also numerous port projects, shipping maintenance and repair jobs, scientific research support posts, etc., that need underwater welders. 

All these companies provide underwater welding equipment and accommodation, they just need divers. 

Underwater welders can find jobs in lots of ways. If you have any connections then it’s time to give them a call. 

Otherwise, you can hit the diving job boards online and start searching. Another good approach is to contact commercial diving companies directly to get your foot in the door. 

The more experience and training certificates that you have, the faster you are likely to get a call-back. 

Underwater Welder Salary

The scope of the underwater welding pay scale varies quite a bit depending on experience. 

A  new graduate can typically start out making anywhere above USD $25,000. Most graduates are making above $30,000 after 6 months.  

The global average in regards to underwater welder pay is $53,990 or $25.96 an hour. The top 10% make above $80,000 while the bottom 10% make $30,000. 

Depending on whether you are willing to work onshore or offshore, the pay rate can vary quite a bit. 

Offshore: Far Out To Sea With Nothing Else In Sight

An offshore welder will find themselves working deep out to sea, usually on an oil or gas platform. 

Typical jobs include maintaining and repairing platforms, installing pipelines and wellheads, repairing damage to support ships, etc. 

Under the usual contact, a diver will typically find themselves working 4 to 6 week shifts offshore before returning for shore leave. 

A recent graduate who is lucky enough to find themselves working offshore is likely to pull in a starting salary of $40,000 to $60,000 per year. 

Divers with 3 or more years of experience can expect to make between $75,000 and $100,000. 

Onshore: Closer To Home 

Onshore divers get slightly less pay because they are stationed on land, and so have the benefits of a normal life. 

Indeed, onshore work can be anything from repairing ships, building ports and other structures, repairing dams and infrastructure like sewers, etc. 

A new graduate can expect to pull in anywhere between $25,000 to $40,000 per year. 

More experienced welders can make between $50,000 and $80,000 per year. 

Some specialist divers, such as those in HAZMAT industries such as nuclear, make more. 

Hard work and connections really do pay off in the commercial diving industry. The formula is simple – do a good job and make yourself indispensable and the big bucks will follow very quickly.

Is Underwater Welding Worth It?

Though underwater welding is indeed a demanding job, the rewards are more than worth it. 

If commercial diving and all the challenges and adventures that come with it are truly in your blood, then underwater welding is a job that will leave you smiling at the end of every day. 

The truth is that there are lots of reasons why many people are not underwater welders, the hard work, and the somewhat strange lifestyle. 

For those that are, the money, the hard work, the somewhat strange lifestyle, and the kick out of being an elite group of people who can do a job that no one else can, is more than enough to keep them going to work every morning.