When repainting a car one can get away with scuffing up old paint and applying a new finish, however, there is only one way to re-chrome old bumpers, emblems, trim, and the like. Chrome can't be laid over the top of chrome, even if the base chrome is decent. Instead, the part must take a trip to a muriatic acid bath where the previous coat is completely removed. At that point the object will go through the chroming process all over again. By the way, don't try this step in your backyard; let a chrome shop do it!
Knowledge Is Power
So far we've covered what chrome is, and what the process is. What we haven't delved into is what you need to know about fabricating your own pieces that will eventually visit a chrome shop. Like we said before, the entire triple-plating process is not a heavy buildup. In fact, it's minuscule, hundredths of an inch thick when it's all done. Therefore, it's crucial to get ones metal as smooth and even as possible before it's sent off-for two reasons. For starters, looks. Chrome is like a mirror, and any defect will be magnified. For this reason make sure all welds are ground smooth and pot-hole free, any and all pin holes, divots, valleys-whatever you want to call them-need to be removed. Trying to chrome over these little miscues is like implanting a prism right in the middle of your ornamentation, and not in a good way! Add dabs of weld to any trouble spots and then grind it back down to ensure everything is following an even keel. The second reason to ensure that everything is smooth is cold hard cash. Remember, chrome plating takes a lot of polishing. The more the chrome shop has to polish your pieces to perfection, the more you're going to pay. Take the time to grind and file your metal to as close to perfection as you can get it. Why spend more when you can take a few extra hours at home to make it right?
Another thing to keep in mind is to not over grind. For instance, take shaved bumpers for example. According to MJB, one thing they often see is guys shaving their bumpers, but over grinding their welds to the point it creates a low spot. On one hand it's good because all the imperfections of the weld is ground smooth with the bumper, but remember, every action has a reaction. And the reaction here is a low spot that will wave at you like the homecoming queen in a parade. If you're unsure about your skills to create an even-flowing piece, then grind your welds close, but leave a little bit of a raised weld for the chrome shop to do the rest.
In the case that one has to fill or fix any defects, such as low spots, and tacks of weld are out of the question, there are options. However, it will jack the price up. For small areas, 1x1-inch areas, one can use brass brazing rod or bronze silica rod to fill low spots and repair imperfections. It is perfectly OK to chrome either of these metals; however, where the extra expense comes into effect is in the copper baths. The reason one would use brazing rod or bronze silica on their parts is because it will flow and grind much easier than steel, which makes fixing an imperfection that much easier. Yet it is because of the soft property of these ores that makes things more expensive. When the chrome shop goes to polish the object the softer metal will dissipate much faster, which could leave the imprint of the area in the finished product. Therefore, the chrome shop will build up a layer or two of copper to ensure a nice basecoat with an even finish, resulting in a hike of the price.
...The bags along the poles...
...The bags along the poles are filled with 1x1-inch squares of copper, nickel or chrome. (see above)
Here's how it all works. Parts...
Here's how it all works. Parts are strung up with copper wires and hooks (for conductance), and hung on the ground poles. Once down in the solution, the electrical current begins breaking down the 1x1-inch pieces of metal into minute pieces that fill the solution with thousands of tiny pieces. The minute pieces are then drawn to the current of the objects hanging on the ground poles, which in turn plates the piece in the desired metal.
Another valuable lesson I...
Another valuable lesson I learned is that pieces welded closed are the most troublesome-because A. they tend to float, and B. they run the risk of taking on solution. If any solution from the previous tanks seeps in through pin holes, there is a risk it will seep out in one of the other plating tanks; long story short; chrome shops won't take that chance. In my case I ended up having to put drain slots at the back of my bars, that way the bars could be drained before they entered the next bath. Once again, this is why it's always a good idea to give a call to guys like MJB with these scenarios-Bill was actually the one who helped me out with the drain solution.