Painting a rusty metal shed
We are in the process of painting a rusty metal shed. We sanded the rust off, washed the shed and applied Rustoleum rusty metal primer. After the primer dried, we painted the shed with Sherwin Williams Exterior Duration paint in white. It has been a few days since we painted and there are little rusty spots showing through the paint. We went to the local hardware store and they told us we needed to neutralize the rust before we painted with naval jelly. We also went to the local Sherwin Williams store and they didn't have a clue what to do. Sherwin Williams was surprised the rust showed back through especially since the Duration paint is also self-priming.
Is there anything we can do? Should we apply the naval jelly to the whole shed and repaint? It will take quite a while to brush naval jelly on the shed. Any suggestions would be appreciated.