yep - pretty straight forward.
If you see the fluid doing the "fish eye" thing, you may need to wash
with soap or degreaser for the Ospho to work properly.
It will not remove grease or oil residue.
For heavy oxidation or corrosion, I would spray on Ospho and scrub with the green
scrub pad to really get into the surface - let dry - wash off - spray on another coat.
Let that one dry overnight as per their instructions.
From the Ospho.com website . . .
NEW METALS - For new ferrous or aluminum metals: remove dirt, grease, or oil; apply OSPHO, let dry overnight, then paint.
For best results, use OSPHO at temperatures no lower than 36 degrees F. Excessive dew and humidity may prolong drying time and cause powdery buildup.
Best results have been achieved using an oil-base primer and topcoat. Test a trial sample before using under epoxy or latex-base paint applications. OSPHO is equally effective for exterior and interior work alike and is highly recommended as a pre-treatment coating by leading paint manufacturers.