Originally Posted by Timelord
The heavy grinding and rust probably removed bulk of the zinc. The 'proper' way to paint galvanized metal is to etch it first. There are etching primers, or you can just give it a spray down with Ospho.
I washed down the floor, TSP'ed the floor to remove all the goop and grease, gave it another hose out. After it dried, I used a pump sprayer to spray down the entire floor with Ospho. Once that dried, I ended up having to fine-wire-wheel the zinc oxide. Don't breathe that stuff. I then put a coat of Rustoleum Pro primer and matching top coat. Worked very well.
Where do I get the Ospho?
The whole interior side areas seem to be rough enough but the center isle is was very well protected so I will need to rough it up or something before coating it.
Again, thanks so much for all the input--it is very helpful as we have no clue what we are doing.