What should I use to protect the insides of my doors and rear wheel wells from rust?

The inside of my door has a little rust, and small areas where there is no paint or rust.

The rear wheel wells had been protected by some thick black stuff that a restorer had applied in the past. Some of that material is peeling up, leaving clean unrusted/unprotected metal.

Any thoughts?

 

www.por15.com then cover that up with some undercoating

 

Spray on truck bed liner once its on its there for life.

 

Rustoleum works on the cheap $7. Once dry its tough as nails. I have a uncle with a 53 ford truck hes had for over 30 years. He did rusteloum years ago and its still on there no rust in those areas.

 

Depends on your driving conditions. If you drive it here and there, no rain or snow, then you can get away with a quick and easy fix, like a rattle can of primer, paint. If you drive it it all kinds of weather conditions, then I would go for a more permanent fix, a good primer and undercoating such as 3M rubberized undercoating or similiar, for the rear wheel wells since they will take more abuse. The inside of your doors are not subjected to the same conditions, you can go with a spray rustoleum or POR-15. I would use rustoleum, it is cheaper and easier to apply. Make sure all metal is clean and prepped before applying any paint. POR-15 is designed to use directly over rust. POR-paint over rust, it converts rust chemically to stop any further advances of it. You can check all options out by researching the products and choosing what best will work for you.