After you put the chicken in the burlap bag how many times do you have to swing it over your head? Does it matter what kind of chicken?
I’ve used a fair amount of Ospho but do not have a lot of experience with large panels. For brackets I make or other parts I clean them well to remove heavy rust then spray Ospho on using a trigger type spray bottle like an empty Simply Green bottle.I let the parts dry well. If there is a residue or build up I might rinse with water and wipe dry with a cloth then let air dry. I have used Scotchbrite to smooth areas also. That’s it! I then prime or paint directly. You want to maintain the iron phosphate surface to protect from further rust and iron phosphate provides and excellent surface for paint or primer. Some Mil Specs require iron phosphate treatment before primer or paint.
From house of Kolor tech sheet NOTE: PLEASE REFER TO SANDING GRIT RECOMMENDATIONS FOR BARE METAL AND OLD FINISH SANDING. NOTE: DO NOT USE ANY ACID BASE PRODUCTS SUCH AS SELF ETCHING PRIMER, ETC. UNDER THE KP2CF PRIMER. THIS WILL ALMOST CERTAINLY CAUSE AN ADHESION PROBLEM. NOTE: IF YOU FIND IT NECESSARY TO USE A METAL CONDITIONER TO REMOVE RUST, ETC., BE SURE TO THOROUGHLY CLEAN AND NEUTRALIZE THE TREATED AREA FOLLOWING THE CONDITIONER MANUFACTURERS RECOMMENDATIONS, USING OUR KC20 POST SANDING CLEANER WITH A MAROON SCUFF PAD TO INSURE ALL ACID RESIDUE HAS BEEN REMOVED BEFORE PRIMING. IF NOT, THIS WILL ALMOST CERTAINLY CAUSE AN ADHESION PROBLEM.
That's pretty much true for all of HOK's primers/sealers. I don't think they have a single one. That's recommended for use, on top of any acid based cleaner or converter.