Welder-assemblers work mainly in factories that make a wide variety of metal products, such as machinery and equipment used for preparing food or extracting and processing ore, agricultural machinery and transportation equipment. They can also work in welding shops specializing in repairs.

Welder-assemblers prepare, assemble and weld metal parts (by applying heat and using filler metal or fusion welding techniques) in order to manufacture, repair or modify mechanically welded assemblies. They use welding set-ups and materials, as well as manual and semi-automatic welding processes.

Welding is a wide field that includes a range of possibilities with respect to the types of parts welded and the types of materials (e.g. mild steel, stainless steel, aluminum), welding processes (e.g. GMAW, GTAW, FCAW, SMAW), positions (flat, horizontal, vertical, overhead), cutting processes (e.g. oxy-fuel cutting, plasma arc cutting, cutting using shears), shaping processes (e.g. bending, shaping, grinding), etc. In addition, welder-assemblers are increasingly required to use automated or robotic manufacturing equipment.

Welder-assemblers should be relatively versatile when it comes to welding processes, materials and so on, although, given the wide variety of processes and materials, they cannot be proficient in all of them. However, the more versatile they are, the more employable they will be. Lastly, they must always avoid compromising their health and safety and those of others.