What are the options for protecting a cast iron keel from rusting and fairing its rough exterior? Having taken it down to clean bare metal it is rough and lower than adjoining surface. What next? The previous owner had applied epoxy from the looks of things. It didn't protect the metal i.e. keep it from rusting. the outside looked nice until a closer inspection showed some blisters. Popping reveiled big flakes of rusted metal. I don't want to repeat that experience.