Epoxy primer is just that---like very thin epoxy glue---you mix two parts together and spray in the time given.I also should have said ---self-etching---which means the primer will "eat" into the metal for a good set.I feel the primer is a very important part as its what really sticks to the metal and the color coat sticks to it.---If anyone is spray-bombing a frame they can use oven cleaner for a cheapo metal prep to get the rattle can primer to stick better.Spray on the oven cleaner wait about an hour--wash off with water very good ,dry and prime.Almost all paints used by auto-shops would be great---especially if you took by some cold beer and they sprayed it with left-over paint(before the beer!).And ask questions too.Like how lone the paint should cure---good luck---sam