Underwater welding is an important part of any industry that involves shipping or structures that are entirely or partially under water. From pipelines, to platforms to ships, metal structures must be repaired, and in many cases can't be removed from the water.

Developing good technology for underwater welding is important. Ideally, an underwater weld ought to be strong enough to permanently be part of the structure. It should also be quick and cheap to implement, without being dangerous - unfortunately, no method can meet all of these standards.

Underwater welding has a number of risks, and must be done by specialists trained to use the equipment and take the appropriate precautions. Underwater welders may be employed by oil and gas industries, shipping companies or even the military.

The two basic types of underwater welding are wet and dry. Wet welding is exposed to the water during the process, and uses electrodes for power. This cheap, fast method of welding can is often done when a structure or ship can't be removed from the water.

The disadvantage of wet welding is that it's never as strong or stable as a dry one. That's because water can cause cold or hot spots, interrupt the welding process, or even create pockets of oxygen and hydrogen that could explode. Wet welds are nearly always temporary, and provide lower elongation percentages than a dry weld.

This means that a wet underwater weld tends to need repair often, and must be inspected regularly for damage. It's an alternative to prematurely putting a ship in dry dock, but not always the cheapest one in the long run.

Dry underwater welding is often referred to as hyperbaric welding. It's usually carried out in a chamber built to isolate the weld from the water outside. This chamber may be pressurized and contain inert gas. Chambers vary from large enough to hold the welder and all his or her equipment to small enough to surround only the weld.

One variant of underwater welding developed by Neptune uses a very small chamber fulled with gas pressurized to one unit above the outside water pressure. This helps prevent contamination and lets the chamber be built quickly and easily. This is one of the least expensive forms of dry underwater welding.

Dry underwater welding is usually thought of as time consuming and expensive, so it's not often used for repairs that must be done quickly. It can be disruptive to ordinary routines, because it's often complicated, but it produces a much stronger weld.

There are a number of risks associated with underwater welding. Shock is a significant danger if the equipment isn't properly insulated or if the welder doesn't observe correct procedure. Decompression sickness is another issue that underwater welders should pay attention to - the right precautions will prevent it, but it could be dangerous, or even lethal.

Every kind of underwater welding has its own problems and benefits. It's important to know what you need out of a weld and the resources that are available. Check out all options, even if they're new to the market, to make sure you get the right solution for your needs.