I'm with Don, that stuff is expensive and just hides what needs to be fixed properly. I would weld in new and paint it.
There is a couple of old guys in Booton NJ, they are the Kanter Brothers,
they have a saying it goes like this "Do it once and do it right".
POR - to me - will just will hide stuff/rust.
That causes more work later on down the road.
Just MHO. Everyone has got one.
This is not to offend people whom have used this product and like it.
Even the Kanters sell POR. I just avoid it as a personal note.
Tom
Huntersville, NC