Bumpers are what started this company. All bumpers are completely repaired before the plating process begins. Twists are taken out and lines/curves are straightened to ensure a good fit on the vehicle. Severely damaged bumpers may require the use of our hydraulic press to get them back into shape. Any dents or dings are taken out with a hammer and dolly and ground smooth. The backs of the bumpers are sandblasted to remove rust and contamination so that plating will stick to the back. Since most bumpers that we restore are more than 30 years old, there is usually rust under the old nickel. We grind these bumpers down to bare metal, remove the factory chops and waves, and then begin the polishing process.
In order for us to produce a mirror chrome finish, the metal needs to be polished before it goes into our tanks. Most of the vintage metal that we work on has rust under the original plating, so we need to remove all the plating down to the bare metal. If you are building steel parts that are going to be plated, you are better off using cold rolled steel instead of hot rolled. Hot rolled steel is full of pits and scale that make it that much harder to polish.
There is no scientific metallurgical standard for pot metal, it is generally whatever metal was swept off the shop floor during production - whether that be lead, zinc, iron, copper, aluminum, tin, magnesium, cadmium, or slag. The main purpose of pot metal is to give plating shop employees grey hair. Due to the inconsistencies in the formulation and casting process, pot metal is prone to pitting, cracking, bending, and distorting with age. All of this means that the plating is coming off and the part is just plain ugly! We have extensive experience in bringing pot metal back to life. Many pot metal parts will be in and out of the copper tanks many times in order to fill pits that have developed over time. This means that we will need to re-polish and often re-carve the detail and sharpen lines and edges that may round off and fill in during the coppering process. We have a specialty welder available that can weld pot metal so repairs can be made. It should be noted that there is some pot metal that cannot be plated due to the presence of excessive amounts of certain metals.
Generally, the first stage of the plating process. After polishing, prep work, and cleaning, the cyanide copper strike tank is the first tank a part will go into. The copper strike is not only a base for adhesion of later plating processes, but also serves to protect the base metal from the acidic copper and nickel solutions so that they will not react and result in peeling. After the copper strike, parts will generally go into the acid copper tank. The amount of time spent in the acid copper is usually determined by how much metal needs to be laid onto a part to fill slight imperfections. Many of our customers bring parts in for just copper plating. When left to the elements, copper will patina and oxidize. This is often desirable for exterior decorations. If needed, the copper can be buffed to a bright shine as well.
On parts that are going to be nickel or chrome plated, the next step after copper is a copper buff. This process heats the copper layer, partially melting it and allowing it to flow into any sanding lines and small pits. The finish produced after copper buffing is a smooth mirror finish which provides a nice even base for a layer of nickel.
Nickel is the second stage in the plating process. It is nickel that provides the deep luster of a chromed part. When you see your reflection in a bumper, you are actually seeing the reflection off of the nickel - through the chrome. Early model cars (pre 1930) used nickel plating instead of chrome. After the late 20s, early 30s, manufacturers started chrome plating exterior parts but left many interior parts in nickel. We also do a lot of work on old wood stoves, bathtub feet, bathroom fixtures, and door hardware in bright nickel. We can also do brushed or satin nickel.
The final step of the process is chrome plating. While most people think of chrome as shiny metal, it is actually a clear protective sealer on top of the nickel which prevents the nickel from tarnishing. Chrome gives finished pieces a blue tint as opposed to the yellow tint of nickel.