Decided to use Por 15 on a 2002 Dodge Ram 2 years ago because it seemed to be the most used and had the best results. This video shows the results of a frame that had light scale witch we wire brushed and did multiple coats of Por 15 just two years before. Por 15 has an Acid in it too help adhere to the rust but I believe it breaks down the metal and keeps moisture behind it making it rust from the inside out. This time we are going to use Zero Rust witch has better results than Por 15.