Chrome Metal Plating - It Don't Mean A Thing If It Ain't Got That Bling

A process called electroplating that uses an anode, a cathode and a liquid bath of the material to be used for plating applies chrome. The simple explanation of the process is that electrical current flowing from the anode carries dissolved metal in the solution where it is applied to the surface of cathode, or the part being plated. But while that sounds simple, in reality the plating process is a complicated chemical process that requires expensive equipment, constant monitoring of solution strengths and temperatures, not to mention strict adherence to a long list of safety and health standards. Sherm’s is a zero-discharge facility, which means they have invested in, among other things, an ion exchange unit that continuously circulates and purifies process water making it cleaner than what comes out of the tap. Although all chrome shops use the same basic plating process, how parts are prepped has a huge impact on the finished product. Art compares chrome plating to a paintjob, in both cases the finished product is only as smooth as the surface below, and the smoother the surface the more reflective it will be. And again like a paintjob, the prep work for chrome is the time consuming, and consequently the expensive part of the process.

When parts come into Sherm’s for plating they are cataloged and inspected. Previously chromed parts are stripped and all parts are mechanically and chemically cleaned. Next, the visible surfaces of the part are smoothed to remove any imperfections. If necessary, some filling is done—lead is normally used for cosmetic fixes while structural repairs call for welding with the base material.

With the prep work done, the next step in plating is the copper coat, which is like primer for paint. In some cases, several coats of copper will be applied and smoothed to make the surface perfect. On many early trucks, trim parts were made from a material often called pot metal. That name came from the fact that “just about anything was thrown in the pot” including zinc, which has a low boiling point.

Consequently, during the casting and subsequent cooling process, air bubbles can be trapped in the part, which ultimately leads to corrosion and blisters in the chrome plating. The only way to repair a blistered pot metal part is to strip it, clean out the pit to get rid of the corrosion, then make the surface level using solder as a filler. However, there’s a catch—lead won’t adhere to pot metal, so the part is given a thin coat of brass. Although solder will stick to copper, there is a compelling reason for using brass. Intricate, ornate design work is often incorporated into the surface of these cast pieces and compared to copper a much thinner coat of brass can be applied to the piece so even the most delicate details can be preserved.

After the part to be chromed is smooth and straight, the color coat is applied, and in the plating process that means a coat of nickel. Nickel provides the shiny reflective surface, but if left unprotected, it will tarnish. Like the clearcoat on paint, to protect the nickel the final step in the plating procedure is an application of chrome. Surprisingly, this is the least time consuming step of all the processes, taking only a few minutes in most cases. But that doesn’t mean there aren’t some tricks involved. Depending on the shape of the piece being plated there may be high and low density areas—that means areas that are prominent are high density and will attract more current and consequently a thicker layer of chrome, areas such as concaves are low density and won’t receive as thick of a deposit. The cure for this is experience and specialized equipment.

While chrome is found on bumpers, grilles, and other parts, stainless steel was often used for various trim pieces; over the years most trucks were treated less than delicately so it’s not unusual for the stainless trim to suffer dings and dents or worse. Fortunately, stainless is a tough material that can often be saved. Much like bodywork, the procedure is to use hammers and dollies to remove dents. In some cases, silver solder is used to repair rips and tears, which are followed by sanding and buffing. When done properly, most stainless repairs are impossible to detect.

We followed the crew at Sherm’s around the shop to get an idea of what it takes to get the kind of results from chrome plating and stainless repair that sets one truck apart from another. CCT