[lupo]

The most durable chassis coating would be a two-component urethane , preferably a polyester based over a acrylic.
in 1988, when I was selling a popular rust product. I was at a show and had my displays out as usual, and the silver had a green tint. A man walked up to my stand, we talked for a while, and he mentioned to me that this primer I was selling was similar to a primer that Mobay had developed. He claimed the Mobay material had little or no sunlight sensitivity and it would do an incredible 8000 hours salt spray. He was the owner of a paint factory in New York State and he attempted this formulation, but on the way home the can burst in the trunk of his car. After that, understandably, he shied away from it. I started asking a lot of questions, but he advised me just call Mobay chemical’s tech department with my questions. You can bet Monday morning I was on the phone with Mobay, where I spoke to an elderly gentleman. Every time I mentioned the black he got a little huffy—his exact words to me were, “It’s silver, like it or lump it.” . I asked him where I could get a can of this silver and he told me to call Steelcoat in St. Louis, which I did, and they sent me a bunch of samples. The first thing I did was paint the front of the 38 Packard. It was stripped down to bare metal, and there was pitting on the top where the hood ornament went. Directions were to spray two coats, and I did exactly that. On the second coat the pitting disappeared...I couldn't believe it! Needless to say, I was happy as a little boy on Christmas.

So that’s how I discovered a way to level pitting without having to use Nitro stain—and this is when the tag line “Get rid of the Pits” was born. In addition to that, we had an airtight seal so the rust couldn't come back, AND we could use any kind of paint over it. The reason for this is it’s completely solvent proof when it dries. So in my first experiment I discovered that it worked well on clean steel, it sealed the rust airtight, didn't turn green in the sun, and dried nice and toothy for paint to adhere to it. I started doing all kinds of experiments with body fillers and glazing putties, and have had great success for many years with these techniques. Not all moisture cures are the same. It amazes me to this day how many other companies copied por-15, it also amazes me that none of these vendors ever restored a car.