{"id":10332,"date":"2025-10-03T11:06:12","date_gmt":"2025-10-03T11:06:12","guid":{"rendered":"https:\/\/www.qceas.eu\/blog\/thermal-lances-how-these-powerful-underwater-cutting-tools-work\/"},"modified":"2026-09-23T09:14:07","modified_gmt":"2026-09-23T09:14:07","slug":"thermal-lances-how-these-powerful-underwater-cutting-tools-work","status":"publish","type":"post","link":"https:\/\/www.qceas.eu\/en\/blog\/thermal-lances-how-these-powerful-underwater-cutting-tools-work\/","title":{"rendered":"Thermal lances: how these powerful underwater cutting tools work"},"content":{"rendered":"\t\t
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A thermal lance is a powerful tool for underwater cutting operations. In this blog, you can read about how these lances work, when divers use them and the safety precautions involved.

\nWhat is a thermal lance?<\/strong>
A thermal lance is a cutting tool that reaches extremely high temperatures by forcing oxygen through a metal tube containing combustible rods. The rod is ignited and then burns at thousands of degrees Celsius, causing the material to melt almost instantly, even while underwater.\nThe rods are usually made of magnesium, which burns brightly and consistently. This allows the lance to make controlled \u2018cuts\u2019 through hard materials. Divers use thermal lances to remove metal objects, cut holes for feed-throughs (for example, in walls) or cut open structures for repair, salvaging or civil engineering work. \n

Why use a thermal lance underwater?<\/strong>
Underwater, visibility is limited, and divers often have very little room to manoeuvre. The thermal lance is specifically designed to work effectively in those conditions.\nThanks to its extreme heat, the lance can burn through steel, anchors and other hard materials without the need for large machinery. This makes the tool ideal for removing obstructions, loosening jammed components and accessing areas where further work is required. \n

How does a thermal lance work?<\/strong>
A thermal lance consists of a metal tube filled with combustible rods. Thanks to the supply of oxygen, the lance can continue to burn underwater, and the oxygen ensures that the molten metal is blown away immediately.\nA spark from a welding transformer ignites the rod, creating a point of combustion hot enough to melt hard materials almost instantly. This combination of combustible rods and oxygen makes the thermal lance a powerful, stable and reliable tool in any conditions. \n

Using a thermal lance underwater<\/strong>\nUnderwater, the diver carefully guides the lance along the cutting line. The constant supply of oxygen maintains the heat, meaning that it operates in much the same way as it would above water.
However, underwater cutting operations requires greater skill. The cutting point is more difficult to judge due to bubbles, slag and, at times, limited space. Because divers work very close to the cutting point, stability, situational awareness and good communication with the team above water are essential. \n

Underwater applications of the thermal lance<\/strong>
The thermal lance is used for a wide range of tasks, such as:\t\t\t\t\t\t\t\t<\/div>\n\t\t\t\t

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