An arc welder is a type of welding machine that uses electricity to create an electric arc between the welding electrode and the metal being welded. This arc produces intense heat, which melts the metal and fuses it together. The welding electrode, also known as a welding rod, is made of a material that melts at a lower temperature than the metal being welded. As the electrode melts, it creates a filler material that helps join the pieces of metal together. Arc welding is a versatile and widely used welding process, suitable for various types of metals and thicknesses. It is commonly used in construction, fabrication, and repair work.