Fender repaint-what went wrong

[cdlong]

I sanded the rust down smooth, but all the rust wasn't removed. I wiped the entire fender with Ospho. 4 coats of Rustoleum cold galvanizing compound. 2 coats of Kilz latex primer. 6 coats of Rustoleum latex semi gloss. Fenders dried 4 days before handling. I nicked a fender putting them back on. paint is pealing off. I can see the wipe marks of the Ospho once the paint peals off. The cold galvanizing compound, primer & paint all bonded well. I can't seperate the layers. Where did I goof up?