Patch panel paint?

What is best paint to use on the backside/inside of patch panel to prevent rust? I am no body & fender guy but have been a welder/fabricator going on 20+ years. I thought I have seen a weld through primer before?
Thanks

This is what i use on my projects both hot rod and 4x4.





http://www.pbejobbers.com/product-2weldthru-primer-copper-450ml-aerosol_59693.aspx

POR 15 or several types from Top Secret Coatings