Certified Welder: Recommended or required skills include physical strength and manual dexterity, reading and interpreting blueprints and specifications; specialises in welding materials together. The materials to be joined can be metals (such as steel, aluminum, brass, stainless steel etc.) or varieties of plastic or polymer. Welders typically have to have good dexterity and attention to detail, as well as some technical knowledge about the materials being joined and best practices in the field All welders will be field tested, prior to employment.