1. Get a ball. Figure out how large you want the ball to be, and choose a sphere of that size. Whatever the object, it must be heavy enough to handle being covered by mirror chips and must be compatible with paint and adhesive. A solid rubber or plastic ball works well.
2. Paint the ball. It's a good idea to cover the ball with shiny silver paint because, as you're about to discover, the mirror chips do not cover every square millimeter of your ball. There are cracks and tiny gaps between mirror faces inevitably, but the paint will make the mirrored surface appear seamless and without gaps. If your plan is a non-traditional, colored disco ball, then choose a shiny paint that matches the color of your mirrors.
3. Now comes the fun with mirrors. The best way to achieve a uniform, classy look is to purchase the mirror chips at a craft store. They are so readily available, and the quality is superior to a chopped up compact disc or other improvised methods that people employ. At craft stores, you'll find bags of mirror chips in different shapes and sizes. Choose square-shaped mirrors for best results. The smaller the chips, the more light speckles it will throw out on a room.
4. Now you can glue the mirror chips onto your ball - one even, straight row at a time, starting in the center. It's crucial that you make sure this first row is straight and level. Work on a flat surface and don't hesitate to use a ruler, string, measuring tape or any other tools as you proceed with this row to make sure it is straight and level. When this first row has dried firmly in place, start on the next row above it and proceed in this fashion, working up the ball row by row. It's a good idea to flip the disco ball over once you are ready to begin work on the bottom half of the disco ball; by flipping the disco ball over, you'll be working above an already dried row of mirrors that can support the new row as it dries. This eliminates the remote possibility of the new row slipping downward along the disco ball.
5. Use a motor to make it spin. The appropriate motor can be purchased from a home and hardware superstore. Many shop selling the water fountains will have one..