Good stuff here, I too have used "sand blasting" with success but there is also a long term problem with paint adhesion, metal man mentioned peening, this work hardens the surface and can cause problems with paint adhesion even after using self etching primer, i suggest you know full well what media your sand blast shop uses, i also know hotrod shops and paint shops have been doing it awhile but in aircraft we never paint something that has been sandblasted.
