A mate has asked me to help him sort the underside of his car as it is starting to show signs of its age. I was wondering what would be the best way to go about this and the best products to use.

I was think of using an angle grinder with a twisted wire knot attachment to remove the underseal then priming using zinc primer then finishing with hammerite smooth. I dont have access to any spraying equipment so has be all done with rattle cans/brushes.

Any advice on method and/or products to use?

Thanks
Dom