What equipment is needed to spray epoxy primer?

Either compressor will work. If you want more volume you can tee the two tanks and run one motor. For just shooting some primer you can get by with a disposable inline dryer snake. Also loop your hose off the ceiling to get some water to drain back to the tank before it hits the snake.

Since all you really want to do is shoot epoxy do it outside. Who cares about bugs, dust, ect. It's gotta be sanded, shot with high build, and blocked anyway.