I should have mentioned this stuff should be applied yearly. If done by the RustCheck centre every year they warrant that there will be no rust through for the life of the vehicle.
The panel on my 46 was faded so I tried an experiment with the RustCheck. I applied about three horizontal beads across the panel and it crept into a solid covering of it. This picture shows the panel. I know it is not 'pristine' but it turned out pretty good. Much better than it was at any rate and the painter thought it was good enough to leave like that as that orignal panel paint seems fussy to do.

http:/www.geocities.com/jarge46/panel.jpg