Milk crates are sturdy containers that are useful for more than just milk. These crates can hold books, knick-knacks and toys. Making a milk-crate book shelf is a way for kids to take part in room decoration.
Measure the dimensions of the space where you want to locate your book shelf. Measure the dimensions of a milk crate.
Draw a plan for your book shelf. In the plan, show how many crates are needed to build the book shelf tall enough and wide enough to fit in the space in your room.
Lay out your milk crates, hole side down, in a configuration to match your plan. You will want to mock build the entire book shelf at this point.
Attach all of the milk crates one to the next both across and down with zip ties. Use two zip ties to attach each edge, one near the back edge of the milk crate's wall and one near the lip of the crate. Trim off the excess on the end of the zip ties with a utility knife.
Move the assembled unit outdoors or to another well-ventilated area. Lay the unit on a tarp or newspapers to protect the surface of your work space. Paint the unit inside and out with a spray paint designed to stick to plastic. Multiple coats have a better result than one thick coat. Let dry between coats as recommended on the paint's label.