On my blazer my two front doors have rust on them with a lil bit of holes and chips missing at the very bottom what would be the best method of repair. i had a 87 astro van that i had to do the same with and the bondo i put on broke off again after a few months, i would like to do it with as much reinforcement with out welding.

 

The only way to repair it properly is to cut out the rust and weld in new metal.

You could just replace the door and repaint it to match...