If going paint/coating my first move would be to roll on Hammerite smooth.
Solvent, gas, and oil dont bother it.
Takes over a week to fully harden but when it does you can hit it with a hammer and it wont chip.
http://www.kilz.com/hammerite/v/index.jsp?vgnextoid=b2fd5f86a6331210VgnVCM1000008a05d103RCRD