Stopping rust

["Walt Goddard" <waltcpa@sierra.net>]

I have been slooowwwwlllly fixing the body on the 77 and cannot seem
to stop the rust.  Sand down to bare metal, clean well with alcohol
(rubbing alcohol, not drinking), and then primer with what's called
self-etching primer.  Supposed to bond to the bare metal.  In all
cases, rust is coming through the primer after less than 1 month.
Is there some type of primer that will stop the rust?  Or is there
some other method I should use when removing dents/scratches?
TIA

Walt Goddard
waltcpa@sierra.net