While most shelves are attached to the wall by means of hardware and mounting brackets, you can also use the less-traditional method of glue. There are advantages of hanging a shelf with glue including the fact that you don't have to locate studs or use power tools. Both wood and plastic shelves can be glued to the wall.
Clean the area of your wall from which the shelf will hang to remove any dust or debris to ensure proper adherence of the glue. Wipe the surface with a mild solution of soap and water and let dry.
Use a fine-grit sandpaper to roughen up the surface area of the shelf that will attach to the wall. Wipe a soft cloth over the surface to remove any dust.
Attach a laser level to a tripod and use it to project a straight line onto the wall where you'll hang the shelf. This line will serve as a guide when gluing.
Apply a straight line of urethane glue along the edge of the shelf that will touch the wall. Urethane glue works especially well to bond different material types together. This type of glue is also one of the strongest available.
Line the shelf up with the projected line from the laser level and press the shelf into place. Apply the pressure for at least one minute until the glue begins to bond.
Place four to five strips of masking tape extending from the wall on top of the shelf to the wall on the bottom of the shelf. This applies constant pressure while the glue cures. Leave in place for 24 hours before removing.
Keep in mind that removing the shelves, once glued into place, will likely damage the wall behind it. Gluing shelves is best reserved for permanent placement. Wood shelves may come with brackets on which the shelf is placed. These brackets can also be attached to the wall with urethane glue instead of installing in a typical manner.