what to use to seal old paint and rust?

[abdywgn]

the tops of the fenders and roof are really taking a beating. New Mexico was kind to the lower body but the upper is faded, down to primer and wipe off rust. what flat or satin clear can be used to seal it until I or the next owner decide on a color and actually paint the car? I tried marine grade clear varnish with UV protection but I think the metal gets to hot for it and it cooks off. a brush on would be better than spray but open to ideas. Thanks!

 

[gzig5]

I saw an ad on Motor Trend TV for a wipe on sealer but don't remember the brand. Looked like a good idea though. Google "brush on patina sealer" and you'll come up with several options. I don't have experience with any of them.

 

[Bodyperson]

Sharkhide