rust never sleeps, seems like that idea's gotten across, I think the major point thats being missed here is really DONT USE PHOSPHORIC ACID TREATMENTS UNLESS YOU COMPLETELY REMOVE & NEUTRALIZE IT PERIOD! you cant have an acid underneath a painted surface w/o some risk of it causing lifting & de-lamination of the painted surfaces above. You then need to sand it off to insure a clean & prepped metal surface thats ready to accept a layer of paint.

For example - if you acid treat then POR 15 the sh*t out of the surface prep you've given yourself the double whammy of potential paint failure. Ospho & other rust treatments are / were created for heavy industry where no one gives a crap how pretty their fishing vessel, excavator or tractor is, they just want practical application methods. A fishing vessel have what 3/8" plate steel ??? so is that going to rust thru or have problems like a car w/26 ga. steel.

Just lose the acid treatment bullsh*t altoghther & you'll all be better off, its the shortcut you dont really want to take. Ask yourself if its really worth the risk then throw that crap out of your paint arsenal!

Or if your a gambler........go ahead & use it just dont bitch when your paint fails.