I tryed about 6 different types found my best results was with a converter from permetex, I sanded the area as much as I could and back to clean metal when possible, and used a brush dont dip the brush in since if cotaminated the chem starts turning and this stuff aint cheap, if you do it like the fine print says after you finished you can drill it or use filler, one tip try to make the suface as smooth as you want before useing since this stuff aint easy to sand and you can use a spray can for hard to reach areas good luck