In this particular entry, I'll give offer some history about moisture cured urethanes and explain the science behind them and , . Originally formulated by the Mobay chemical company in the early 1970s, this coating system was designed for maximum corrosion resistance on bridges, structures along the sea front, and any other -corrosive environments. It worked on a simple principle that the resin being moisture activated and waterproof would be heavily impregnated with aluminum pigment, when applied in layers, would cut off the oxygen. It was first introduced in the mid-70s as POR-12 metal filler. After the owner died a new owner arrived and that marked the end of POR-12 metal filler. His logic was that customers who are painting the bottom of their cars don't want silver, but black instead. This black was coating was then created, but it was not the same as the silver--without the aluminum pigment to cut off the oxygen, it was not air tight. I had been working for that company, and that's when I left and started my own Coating Line. Since that time, a number of companies have appeared and sell the black coating the same way: they all claim that the black is air tight and will stop and prevent rust by itself. This is not true. The fact of the matter is that aluminum flake and metacious iron oxide and Mica cut off oxygen, and if a coating does not contain one of these, it is not air tight. For 30 years now, we’ve been using two coats of silver then a black. The name of this coating system is the Three Coat Polyurethane System, which consists of two coats of the aluminum base primer and one color coat. This system provides a service life of up to 25 years, rust free.That's the facts. This is a section from my blog that I have edited out the name of our products.
I’ve used POR15 and epoxy primer in different situations. If the metal is rusted you need to do something to it apart from how you would treat sound metal. I used POR15 on some sub rails from 1931 - rusted but sound. I also used it on some fresh sheet metal floors and a sand blasted 1931 firewall. On non rusted metal you need to prep it properly - that means their degreaser and metal prep (etch) products first. It seems fine to me, but I just did it last year. It is UV sensitive, so if the painted area will see sunlight it needs to be top coated (starting to sound like their web page). I used the POR15 black as well as their silver. The silver has lots of metal particles in it and seemed to help smooth out the firewall after sandblasting. It would be hard to beat epoxy primer on clean metal.
In a industrial environment in a lot of cases project engineers will specify two coats of the aluminum pigmented moisture cured NON LEAFING. The second coat is an epoxy to promote adhesion. It's then top coated with a two component urethane. Generally a two component polyester urethane is preferred because of the excellent chemical and acid resistance. This system was used to paint the conveyor belts at a South Carolina's coal-fired generating plant on the Atlantic that was subject to the salt air and severe coal dust corrosion. The Hallandale Florida beach ball attraction same system. Same system on my 55 that you see in my avatar.I can understand for a lot of you don't care about coating systems such as these. A lot of you prefer rust oleum. Some swear by epoxy ,all well and good. Everybody has a different outlook on what they're trying to accomplish.
If you have rust, that you cannot remove, for practical reasons, like deep inside a structure, I recommend this: http://www.pettitpaint.com/products/primers/above-the-waterline/rustlok-steel-primer/ It is loaded with aluminum, much as the coating in the process that @Pats55 mentions. There are things that had surface rust on them, where I painted with this, and then top-coated, in New England, that live outside, in the late 1980's that still have yet to rust. If it is exposed to light, you need to top-coat it, and that is done when the surface is tacky, so the layers tie together. The inside of every single thing that I have built, on the West Coast, has been coated with this. Over 200 vehicles, over 20-years. Zero issues. Some of these vehicles live within sight of the Pacific Ocean, where late-models show rust-through, in 10-years. Just like similar coatings, keep it off of your skin, and don't spray it.
Here is a re-post of @Pats55 teeny font infor, for us vision impaired dudes: "In this particular entry, I'll give offer some history about moisture cured urethanes and explain the science behind them and , . Originally formulated by the Mobay chemical company in the early 1970s, this coating system was designed for maximum corrosion resistance on bridges, structures along the sea front, and any other -corrosive environments. It worked on a simple principle that the resin being moisture activated and waterproof would be heavily impregnated with aluminum pigment, when applied in layers, would cut off the oxygen. It was first introduced in the mid-70s as POR-12 metal filler. After the owner died a new owner arrived and that marked the end of POR-12 metal filler. His logic was that customers who are painting the bottom of their cars don't want silver, but black instead. This black was coating was then created, but it was not the same as the silver--without the aluminum pigment to cut off the oxygen, it was not air tight. I had been working for that company, and that's when I left and started my own Coating Line. Since that time, a number of companies have appeared and sell the black coating the same way: they all claim that the black is air tight and will stop and prevent rust by itself. This is not true. The fact of the matter is that aluminum flake and metacious iron oxide and Mica cut off oxygen, and if a coating does not contain one of these, it is not air tight. For 30 years now, we’ve been using two coats of silver then a black. The name of this coating system is the Three Coat Polyurethane System, which consists of two coats of the aluminum base primer and one color coat. This system provides a service life of up to 25 years, rust free.That's the facts. This is a section from my blog that I have edited out the name of our products."
Thank you I cut-and-paste this from my blog which is a major accomplishment for me. Thanks for backing me up we old-timers need to stick together
The Jalopy Journal
