You can make floating shelves from lightweight, inexpensive hollow-core doors. They’re perfect for displaying collectibles, photos, and travel mementos or just about anything. These shelves are strong, too.

Recognize that each shelf is made from half of an 18-in. hollow-core door. Cut the door blank lengthwise after clamping a straightedge guide to the door. Be sure to use a 40-tooth carbide blade for a smooth cut. Don’t exceed 9 in. Wide or you’ll start to weaken the cantilever strength of the shelf.

Cut a cleat to fit inside the door. Measure the space between the outer veneers of the door and cut cleats from a 2×4 to this thickness. Make the cleats as long as the inside of the door. Use straight, dry lumber for cleats.

Trace the horizontal location for each shelf using a 4-ft. level as your guide. Use a stud finder to mark the locations of the studs and lightly press masking tape over each one.

Bolt the cleats to the studsPredrill 1/4″ diameter holes at the stud locations after you cut the cleats to length (the measurement between the end blocks of the door half). Hold the cleat to your line on the wall and drill into the stud with a 1/8-in. bit. Using a wrench, install one lag screw into each stud until it’s tight. Use 1/4-in. x 3-1/2 in. lag screws. Each cleat must be straight.

Make space for the cleat. Cut away the corrugated cardboard cores at least 1-1/2 in. from the cut edge. Scrape away the glue carefully without gouging the wood surface. A bread knife works well for this.

Dry-fit the shelf to make sure the blank fits over the cleat. Check the backside of the shelf and scribe it to the wall if necessary. Use a block plane or sander to remove material from the back edge for a tight fit.

Glue the shelf to the cleat. Apply a generous amount of glue to the top of the cleat and the inside bottom edge of the door blank. Slide the shelf over the wood cleat. Or, if you don’t want these mounted permanently – just slide the blank over the cleat.

Fasten the shelf. Nail the shelf to the cleat using a square as your guide. Start at the middle and work your way to each end. Use 1-in. brad nails spaced 8 in. apart. Nail the bottom also. If you wish for the shelf to be removable (and didn’t apply glue), use counter-sunk screws instead of brads. Install them from the top, and use a small sticker to cover the head. The paint used on the shelf can be used to touch up the stickers, to match.