One of the most important visual aspects of a muscle car are the shiny parts, you know, the chrome. Fresh paint trimmed out with dingy, dented and rusted bumpers, as well as other brightwork, detract from the overall fit and finish of any example of Detroit iron. With the EPA’s ever-increasing environmental controls, however, the days of the local chrome shop have gone the way of AMC. Not that the EPA controls are a bad thing, but just a few of decades ago these chemicals were simply dumped into the local creek, not a good thing.
What we are left with are a handful of regional and national chrome houses that specialize in restoring bumpers for body shops, restoration shops, and individuals. While the majority of their business comes from selling plastics bumpers for auto body shops, about a third of the bumpers sold are for cars and trucks up to about 10 years old. Where this matters to you is that these chrome shops run hundreds of bumpers a day. This means that the overall cost of plating your bumpers will be much less than at a smaller shop that may or may not have the ability to properly apply the nickel and chrome that is needed to create a lasting finish. That and there are a few of these shops that kind of side-skirt the EPA regulations and that is just, well, illegal. Besides that, the majority of smaller chrome shops use smaller tanks, which work great for them because they require less room, less chemicals and are easier to control the levels of chemical vapors in the air, which is the main gripe of the EPA and OSHA (Occupational Safety and Health Administration). The problem is that these smaller tanks don’t have the space for large bumpers typically found on 50s through early 70s cars. In these cases, most local chrome shops actually send the bumpers to a regional chromer.
A common problem with chrome shops is that they simply clean and replate the metal. After years of parking lots, flying rocks and other road hazards, most bumpers have a few dents, dings and twists that need to be fixed BEFORE being plated. Chrome plating is just like paint, you can’t bump out a dent afterwards or the plating will crack and flake off. There are several steps that the platers take through the process, and as the bumpers move through, they are sent back to the previous stage if something is found. It is rare that a bumper makes it through the process with a flaw, though it does happen.
There are 2 types of chroming, double plate and triple plate. Most people consider triple-plated chrome to be the best. The problem with triple plated chrome is that the EPA has regulated this process almost into extinction. There are very few chrome shops that continue to triple plate chrome. The triple plating process consists of 3 stages; copper plating, nickel plating, and chrome plating. The copper stage is the issue here. This process is so dangerous to both humans and the environment that it is just not safe to perform it. The vapors cause too much damage even at very little exposure levels. Double-plating involves the nickel and chrome stages.
The real meat of the process is the actual chemical dipping. There are several stages to this process. First, the polished steel must be cleaned in a caustic soda bath, then rinsed, and then hung on the belt system. The actual plating occurs in 2 tanks, the nickel tank, which is what provides the reflective shine, and the chrome bath, which is actually just a sealant to protect the nickel from tarnishing. The bumper soaks in the nickel tank for 45 minutes to an hour while the electroplating process works. How this works is by negatively charging the metal bumper and placing it in the positively charged bath. The nickel is held in 50-60 bags hung on the side of the tank. These bags hold the nickel “coins” (not money coins, but about the same diameter, 1\4-1\2-inch thick) which then melt into the solution of nickel chloride, nickel sulfate, boric acid and sulfuric acid. This chemical balance must be maintained to strict tolerances or the result will not be suitable for use. The 45 minute to one hour time is important because if the bumper is left in too long, it will have a rough orange-peel finish. The bumper is then rinsed in a couple of acid and water rinses, and then the bumper spends the next minute in the chrome bath. Once the chrome is put on, the bumper is rinsed in a final wash, and drip dried.
Having your bumpers plated with fresh chrome will do wonders for the finish of any muscle car, restored or not. We had the chance to follow a regional plater, to see the process from drop off in Oklahoma City, to Dallas, and back. The price for a single Buick GS bumper ran $360, which is not bad considering that it carries a lifetime warranty.