por 15 is a coating they make frame paints and primers that are 100 bucks or better a gallon good stuff withstands heat and dries very hard.
jimmy at the shop here has drained the oil and clened it very well,and used a gel epoxy from napa to fix a few.
its a 2 part epoxy that mixes as you push the handle.
i myself usually clean pan good after draining and grind rust off a big area after treating and epoxying,and then i take a piece of sheet metal and weld a patch over bigger then the square area.
