stripping a patina Duster hood

Is Eastwood Fast Etch just diluted phosphoric acid.Their tech say you only need to wipe with paint prep before top coating and bare metal can be left nearly indefinitely without flash rusting.
Also leaves zinc film to promote paint adhesion.
If it's the same as hardware products diluting is a great idea but a gallon of Eastwood Fast Etch will do more than a whole car.