How do I keep the coating from going over the project edge?

Use Auto Body MaskingTape to dam upsides, breaking? A re-attaching strip of tape every 3 feet to relieve tape stress. Rub on straight sides of the project (rounded sides cannot be done) Pour coating at room temperature of 70*. Remove tape after 3.5 hours. Epoxy will slump into a soft rounded edge after that point.