1. Place the wooden ball on a drop cloth (outside). Spray one coat of primer, and let dry. Flip it over and spray the other side. Let dry. Likewise, spray two coats of paint on each side, letting it dry between coats.
2. After the paint dries for several hours, attach the ball to your lamp’s original finial. The brass finial from my lamp fit perfectly into the hole of the ball. All I had to do was press them together for it to fit snugly. Depending on the size of your finial, you may have to glue it—or buy a new finial. This one might work.