As an 'aside' question, does anyone know how many years the cad plating usually lasts? So how long before it has to be done all over again?
Cees, that's an impossible question to answer as it has everything to do with the environment which is different for each car and owner, and what kind of plating was done (quality, thickness, treatment, etc.)
However, keep in mind the following: true CAD (cadmium plating) lasts longer than zinc plating. More often than not (guessing) people are having zinc plating done (which is silvery in color) and then the phosphate wash (which adds the gold color) as opposed to cadmium, merely because cadmium plating is harder to find.
That being said, the industrial measurement of how long these platings last is usually done with what is called a "salt spray test". G-d forbid we would ever subject our cars to such a horrific environment. A typical standard would be found under ASTM B766, and an end result might be 480 hours of salt spray to red rust. That's for Cadmium.
For zinc plating, the duration to red rust can be as little as 12 hours. The most common zinc specification is ASTM B633-07.
Pardon the pun--but take this with a "grain of salt". There are so many factors influencing corrosion, and the quality of plating...it pays to study and research. Thickness of plating, plating standard, phosphate washes, etc. all make a huge difference in how long things last. Talk to a few platers, do a little research, find some materials finishing books, and arm yourself with some knowledge.
Concluding, let me quote one plater here: Cadmium use in harsh environments and aerospace application has no equal and Cadmium is second to none in aquatic or brackish application. There are some that say you cannot find cadmium plating, and that's silly. There are plenty of platers around, they just take a little more work to find. I've had cadmium plating done. Cadmium plating will only go away when we stop making military aircraft.
My car: nearly all of the interior parts were done with barrel zinc plating with a gold phosphate wash. The restorer chose to go local, and there were no local cadmium platers. After 12 years now, a good deal of the brightness of the color has faded. While there is no rust, and only minor signs of corrosion, the engine bay parts are ready for another round of plating. When this happens--and I don't know when that will be--they'll be done in Cadmium, not zinc.
I have just finished doing all the cad plating in the engine bay on mine. Here are some photos
Garry--absolutely stunning! I only wish I could see the car in person.