Eric, this is my expertise.  Just did one whole van and am working on another at this time.  Two methods I have had great success with.

Use POR-15 and FOLLOW the directions, then prime with high build primer, then paint.

Use Rust Converter, Follow the directions, then prime with high build primer, then paint.  This method is less labor intensive.

Use Crown rust preventive film on all surfaces to install the window

> On Feb 28, 2025, at 12:00 AM, Automatic digest processor <LISTSERV@GERRY.VANAGON.COM> wrote:
> 
> Rust treatment process and products?

Cheers,    

Frank Condelli
Almonte, Ontario, Canada
'87 VW Westy, '00 Kawasaki 250 Sherpa, "98 Ducati 750 Monster 
Vanagon/T3/Westfalia Information
BusFusion <http://www.busfusion.com/> a VW Camper camping event, Almonte, ON 
Lionel Trains (Collection for sale) <http://www.frankcondelli.com/trainsal.htm>