Arc welding
From Halopedia, the Halo wiki
The Arc Welder is a heavy-duty piece of machinery used by the UNSC on its starships. Arc Welders are multi-person machines, weighing 200 kilograms, though it should be noted that a person wearing MJOLNIR Armor could heft the machine with ease. Arc Welders are large welding instruments designed to fuse starship-grade plating into place.
