This question takes many different forms: some people have the very specific idea that they want to gold plate brass buttons or chrome plate carburetors; others want to be able to plate anything. Some want to do it once to repair an heirloom, or a few times as a hobby; others want to do it as a small business. Most want to start in their basement or garage; only a few want to do it in a properly designed factory.
There are a few types of plating that are relatively easy, for example, gold plating of auto emblems. Why is this fairly easy? It's not only because the parts are small but because, even after the replating, you are relying on the factory plating job for all of the corrosion resistance and most of the appearance. These emblems were polished and buffed, copper plated, plated with two heavy layers of high quality nickel, then flashed with chrome at the factory. All you are doing is removing the chrome flash and replacing it with a gold flash. The original plater solved the preparation problems, any adhesion issues, and the corrosion resistance problem; the original plater provided the smoothness and shininess that makes the gold plating look good. There is a gigantic difference between starting with a beautifully nickel plated emblem and starting with a raw casting :-)
With the exception of plating some simple things like jewelry or car emblems, it is expensive to get into the plating business. And it is foolish to mess around without adequate knowledge, in a business where many have been killed or seriously hurt (and dozens have been sent to jail). Please treat as quackery any promise that plating is easy.
For those who want an heirloom plated, you can look up 'plating' in the Yellow Pages for a local large city, or see www.finishing.com/shops/ for a list of plating shops, or post an RFQ. Plating is a jobshop oriented business, and you don't have to plate it yourself if you don't want to.
For those who want to do plating as a hobby or a very casual business, please think carefully; due to the inherent hazards in working with toxic materials, and the ecological and legal problems of dealing with the inevitable waste products, plating isn't a great hobby, and is very heavily regulated as a business (even innocuous rinse water is regulated as hazardous waste).
For those considering plating as a real
business, please join us, this industry needs new blood --
but do it with your eyes open.
A Quick Science Lesson
First, a couple of paragraphs of easy science. Part of the quackery you may hear is that you can just 'dip' the parts. This would be like reporcelaining your sink without even moving or washing the dirty dishes that are sitting in it. It is nonsense. Plated coatings require metallurgical bonds: if the plating is not to blister off when the item is put into service, the plated coating must atomically bond to the surface. This means that the surface metal must be utterly free of oils, grease, wax, rust, tarnish, and passivity. There is no good way to do this except to clean the parts in very strong hot caustic cleaners and then acid pickle them immediately before plating.
When something is 'chrome plated', sometimes it means cleaned, etched, activated, palladium-tin plated, electroless copper plated, electrolytic copper plated, semi-bright nickel plated, bright nickel plated, and THEN chromium plated -- with multiple rinses between each set of steps. Many plating processes require post-treatment steps after plating as well. It can be rather involved, usually requiring at least 15 different vats of chemicals and sometimes as many as 50, to do just a single finish on a single type of material. We have an FAQ on line that explains this by describing the steps in chrome plating in detail.
The Politics of Plating
Next, the politics: the electroplating jobshop industry was the country's very first EPA-regulated activity; the first industry for which "categorical standards" were issued. What that means, somewhat simplified, is that all waste products, no matter how innocuous, are "categorically" hazardous waste for which you are responsible forever, no matter how much you pay for disposal. Part of this was probably due to the fact that it is easier to intimidate Mom & Pop shops than giant corporations; but part of it is the reality that plating inherently involves strong acids, caustic soda (lye), chromium, heavy metals, and cyanide. Multi-million dollar aquifer cleanups have been necessitated by leaks from very small plating shops. And it is impossible to go from one step of the plating process to the next without copious rinsing. What will you do with that rinse water as it grows too strong to use any longer
Don't Even THINK About Chrome Plating At Home
Plating involves dangerous chemicals, some of them carcinogenic, some of them rapid acting and powerful poisons. Lethal gases can be easily released if you don't know what you are doing. If the process demands cyanide, chromic acid or hydrofluoric acid, would you have these in your house or garage? I wouldn't have them in mine, I promise you.
If you will accept that it isn't easy, that you're not going to do it in a residential environment, and that you'll need to learn a lot first, then . . .
Here's How To Get Started: