finishes

The steps for gold plating are much the same as for brass (see "What is Electroplating?"). However in this case the gold is dissolved in a solution and exists as individual single ions of gold. When deposited onto the nickel substrate the gold deposit is virtually pure gold (24 carat). Because gold is such a stable material (it does not corrode) then the thickness can be reduced to less than 1 micron. The biggest problem with gold is that it is a relatively soft material and hence when there is any likelihood of wear a protective coating is applied. Components likely to be requiring this coating include things like door handles, tapwear or handrails.

The protective coating can be a urethane coating as is used for brass or another alternative is the use of what is termed an 'electrophoretic' coating. This is where the urethane or acrylic is present as charged ions in an aqueous solution and is deposited by a plating process. At Astor we use both systems and the electrophoretic process used is 'Clearlyte' which is acrylic based. These finishes are used for tapwear and door fittings as the surface is quite hard wearing. A third alternative is to apply a clear powdercoat finish. The drawback with both electrophoretics and powdercoating is that the finish is not as clear, is thicker and can change the colour of brass and gold slightly.

Since the 1930's chrome plating has been synonymous with electroplating and even today by far the most common form of plating is still with chromium as the final decorative coal. Unlike gold or brass plating, chrome plating needs no further protection. The secret to chrome plating is that the chrome forms a very hard oxide coating which forms rapidly but then protects the surface from further oxidation and is also very resistant to wear. In fact there is a process called 'Hard Chrome' plating and this is done specifically to improve the wear and life of components such as crankshafts. It is for these properties that chrome has remained so popular for so long.

There has been a revival of chrome plating with popularity of some of the more natural metallic finishes such as brushed or satin chromes.

Unlike the standard bright chrome, brushed chrome is done by carrying out a satining polishing process after having first done a conventional nickel plating. Following the satining process the component is then replated with chrome as before and the result is the soft brushed appearance. This finish is quite a good match with the 'No 4 finish' of stainless steel.

Antique finishes include Florentine bronze, antique brass, pewter and verdigris. These are undertaken by using several layers of plating and then applying artificial aging of the surface. This is then followed by relieving by buffing back to show as much of the substrate as required to match the finish desired.

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