[header] How to hang shelves without nails [title] Get a shelf made of a light, hollow material. [step] Unfortunately, fasteners like nails are necessary to hang up extremely heavy shelves made of dense, solid materials like steel or oak. However, you can use adhesive fasteners to hang up light, hollow shelves made of things like balsa wood. 
As a general rule, try to hang shelves that weigh 3 lb (1.4 kg) or less. [substeps] For safety, do not attempt to hang shelves with adhesive strips if they weigh over 10 lb (4.5 kg).