My approach to media blasting a classic car body has evolved over ten years from over-aggressive to appropriately precise.

Sodium bicarbonate blasting is the gentlest option. It removes paint and light rust without profile-etching the metal the way sand or walnut media do. The downside: it's slow, the media isn't reusable, and it won't remove heavy rust.

Glass bead is my current preference for most panel work. It removes paint and surface rust, leaves a consistent profile that promotes adhesion, and is fast enough to be practical on a full body shell. It does not remove heavy rust pitting.

Media blasting a full body should be followed immediately with an epoxy primer coat. Bare metal oxidizes within hours in humid environments. If you can't get the primer on the same day, use a temporary rust inhibitor.