If you can use a sand blaster, this way u will see any real defects in your frame because sandblasting works in three ways; 1. removes paint work 2. clears out dirt and muck out of scratches and strips the frame material back to a better finish 3. leaves the frame slight rough so the primare will stick tot he frame easier which helps prevents runs. Then you should put a layer of lacker or 'clear' on to your final coat of paint to help pretect your frame, hope this helps send me a picture when your done