No street rod project is complete without a really righteous chrome job. When done right, it turns a funky ride into a gleaming triumph. If you hit it wrong, though, the effect can be like a glamorous model with a gap tooth.
To get some tips on correct chroming, we went to Shaver Automotive Restoration, a company that specializes in revitalizing hot rods and classic cars. During our visit, we checked out a table full of metal trim pieces in need of attention. Some could be repaired, while others were just too far gone, and would be a waste of time to have re-plated.
There’s another caution to keep in mind when re-plating. This process can present some special problems, especially when re-plated parts need to visually match older plated parts on the vehicle.A re-plated chrome part may not look the same as surrounding components due to a change in the way parts are chromed.
Originally chrome plating was done with a hexavalent process, which produced great looking chrome but was later found to be toxic to the workers who did the plating, and introduced deadly chemicals into the environment. A new chrome-plating procedure called trivalent plating was invented to reduce these dangers.
Trivalent is not as tough as hexavalent, but it is less susceptible to discoloration from heat. The biggest problem is that it usually has a darker and slightly brownish tint compared to the lighter, bluish tint of hexavalent. Unless you have two parts side by side, it is almost impossible to see any difference. However, if you are only planning on re-chroming only some of the body trim on an older street rod, the new parts will not be a visual match to the older pieces.
Hexavalent plating is gradually being eliminated around the world, so it is getting harder to find shops that will do it. A few specialty platers still offer hexavalent plating, but it’s expensive. If you are re-plating all the trim on a vehicle, then using trivalent for everything is a more affordable option.
In deciding which pieces are worth saving, the first step is a careful inspection, both inside and out. In addition to any dents or dings, look for corrosion and poor welds. Minor pitting on the surface is not usually a problem, but if rust is starting to eat away at the metal, the part may need to be replaced. The problem is that if the metal is too thin, during grinding and polishing the friction produces heat that can distort the surface and create ripples.
The chrome-plating procedure is fairly simple. First, parts are cleaned and, if needed, bead-blasted. Old plating can be removed by dipping in a caustic acid solution, or with a “reverse plating” procedure. Once the part is squeaky clean, it is buffed on a wheel with progressively finer buffing compound until the base metal is perfectly smooth.
If the base metal is pitted it must be welded up or ground down until smooth. Chrome does not act as a filler material and even tiny pits or scratches will be visible through the new plating job. Do the buffing and repair work yourself, and you will save money at the platers. Much like a paint shop, the cost of materials is small compared to the labor involved.
After the part has been chromed, Shaver recommends coating the inner surface with a rustproof silver paint in order to protect against corrosion that can migrate to the outer surface.
Chrome-plated parts are not as durable as they might seem. Unless they are properly cared for they can tarnish, discolor or even flake off. Plated parts should be cleaned by hand with mild soap and water, avoiding harsh cleaners, abrasives and commercial car washes. Do not buff chrome parts or use excessive wax coatings (some chrome experts advise using no wax at all), although small scratches should be touched up with clear paint to keep corrosion from getting started. Take care of your chrome and it should stay shiny for years to come.
One more tip: a lot of chrome shops have long lead times, so start on those trim parts first, because you may have to wait several weeks or even months before you see them again.
Shaver Automotive Restoration
1942 W. Artesia Blvd.
Torrance, CA 90504