So your 67 Cali car had no rust when you beaded it? And you said you beaded your car before you disassembled it...is that correct? What did you disassemble? (Would it have been better to disassemble the car first then bead it?)
What about beading the car first then go back and use a harder media where rust is visible? (and filler, etc.)
Would the plastic bead dust soak up water? (which would be back the rust)