Many folks believe that the ability to weld makes one a metal fabricator. Yet, not all metal fabrication involves welding. Some pieces are connected with nuts and bolts or rivets, some pieces are bent, twisted or rolled into another form, and some pieces are machined. While welding is a relatively new technology, blacksmiths have been fabricating basic necessity products, farm implements, tools, and art from metal for a very long time. To properly attach metal to metal, one needs to understand the properties of the metal: what kind of metal is it--iron, steel, aluminum, or an alloy mixture? What will the final use be--decorative, structural, artistic? These questions can affect both the design and fabrication of a metal project. Structural steel fabrication usually involves using very heavy steel and specialized welding materials. The framing of high rise buildings is often made from structural steel. Decorative, ornamental and architectural fabrication is used in commercial, industrial and residential applications--deck rail, stairs and gates. Pieces that need to be strong yet lightweight such as bicycles, airplane fuselage and race cars can be made from a variety of lightweight metal alloys. Metal fabrication artists often use reclaimed metal or scraps, and art can range from sculpture to abstract.