Can You MIG Weld Underwater?

Underwater welding is a highly specialized field that requires both diving and welding expertise. It is primarily used for repairing and maintaining marine structures, offshore pipelines, oil rigs, ships, and even nuclear power plants. The two main types of underwater welding are dry welding (hyperbaric welding) and wet welding.

Dry Welding (Hyperbaric Welding)

Dry welding, also known as hyperbaric welding, involves the use of a hyperbaric chamber to create a dry environment around the weld area. This method offers several advantages over wet welding:

  1. Better Visibility: The dry environment allows the welder to have better visibility and control over the welding process, leading to higher-quality welds.
  2. Reduced Defects: The controlled environment minimizes the risk of weld defects such as cracking, porosity, and inclusions.
  3. Improved Weld Strength: The absence of water pressure and the ability to use standard welding techniques result in stronger, more reliable welds.

However, dry welding also has some drawbacks:

  • Specialized Equipment: Dry welding requires the use of a hyperbaric chamber, which is expensive and complex to set up.
  • Higher Costs: The specialized equipment and the need for a dedicated support team make dry welding a more costly option compared to wet welding.

Wet Welding

can you mig weld underwaterImage source: Mig weld example

Wet welding is performed directly in the water, without the use of a hyperbaric chamber. This method relies on the bubbles created by the shielding gas to cover the weld area and protect the diver. While wet welding is generally less expensive and more accessible than dry welding, it also has some significant drawbacks:

  1. Reduced Visibility: The water and bubbles surrounding the weld area can make it difficult for the welder to see and control the welding process, leading to a higher risk of defects.
  2. Increased Defects: The water pressure and the presence of water around the weld area can increase the risk of weld defects such as cracking, porosity, and inclusions.
  3. Lower Weld Strength: The water pressure and the inability to use standard welding techniques can result in welds with lower strength and reliability.

Underwater Welder Training and Certification

To become an underwater welder, individuals must first be certified welders and then complete specialized underwater welding training. This training can take several years to complete and includes the following key components:

  1. Diving Certification: Underwater welders must be certified divers, typically with advanced or commercial diving certifications.
  2. Welding Techniques: Trainees learn specialized welding techniques, such as the use of waterproof welding equipment, shielding gas management, and weld joint preparation.
  3. Underwater Safety: Underwater welders must be trained in underwater safety protocols, emergency procedures, and the use of specialized diving equipment.
  4. Weld Inspection and Testing: Trainees learn how to inspect and test underwater welds to ensure their quality and integrity.

Risks and Hazards of Underwater Welding

Underwater welding is considered one of the most dangerous professions, with a high fatality rate. The primary risks and hazards associated with this field include:

  1. Drowning: Underwater welders face the constant risk of drowning, especially in the event of equipment failure or unexpected emergencies.
  2. Explosions: The combination of welding and the underwater environment can lead to the risk of explosions, particularly when working with flammable materials or gases.
  3. Electrocution: Underwater welding involves the use of electrical equipment, which can pose a significant risk of electrocution if not properly maintained and grounded.
  4. Decompression Sickness: Underwater welders are exposed to changes in water pressure, which can lead to decompression sickness if not managed properly.

To mitigate these risks, underwater welders often invest their earnings to retire early, as the physical and mental toll of the job can be significant.


While it is possible to MIG weld underwater, it is a highly specialized and dangerous profession that requires extensive training, specialized equipment, and a deep understanding of both welding and diving techniques. Underwater welding is primarily used for repairing and maintaining marine structures, but it comes with significant risks and challenges that must be carefully managed. Those interested in pursuing a career in underwater welding should be prepared to invest the time and effort required to develop the necessary skills and certifications.

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