Crackle, Craze and Other Textures
The process involves using two coats which dry at different speeds. As the slower-drying base coat stretches and hardens, the quicker-drying top coat has already lost flexibility, and cracks and crazes in random, uncontrolled patterns. For clear finishes, you must use a spray gun, probably for the base coat but certainly for the top crackle enamel, which is a special preparation sold as such.
Source:Crackle, Craze and Other Textures
