Yes, I add a small amount of water, using a cap from a plastic water bottle. I fill the cap two times and pour it in. The water helps the enamel lay out over the surface better. Emerald urethane is a little tricky to spray at first until you get a feel for how the product performs. If you spray cabinet doors laying flat, which I recommend, you have to build up the coats as you spray. Start with one light coat, moving the spray gun fast, then make two more passes, moving the gun slower to build up the coating. With Emerald urethane, you have to spray a thick and even coating. When spraying doors horizontally, Emerald levels out really nice if you spray on the right thickness. If you spray it too light, you'll get an orange peel effect, or rough textured look with small air bubbles. I definitely recommend practicing on some spare pieces of wood first.