If you are considering a metal faucet, sink or countertop for your kitchen or bath you may have heard the term “living finish” or perhaps “organic finish”. Any metal besides stainless steel that is not coated with a sealer or a metal finish such as chrome will acquire a “patina” over time. This means the finish will change and evolve through exposure to the environment. Some call this “oxidation” (exposure to oxygen) but this patina process is also caused by other environmental factors that the metal surface might come into contact with as well as wear resulting from regular use.
When applied to plumbing fixtures, the question comes up most often regarding copper sinks. Faucet and drain hardware manufacturers generally address this issue with certain coatings that protect the metal surface from the environment, thus preventing patina or changes in the finish. However, these types of coatings (PVD or other types of clear protective finishes) are more difficult to apply to a larger surface area such as that of a sink and require a more “production” like manufacturing process. Thus many of the artisan crafted copper and bronze sinks are not sealed and will have a true living finish.
Metal products with a chrome finish or stainless steel products are often referred to as “non-living”. This is only partially true. The surfaces of these products can, in fact, dull over time depending on the environment and how well they are cared for. We have also heard nickel referred to as “non-living finish” but the fact is that nickel will patina or “tarnish” as well. However, this process is significantly slower than unprotected copper or bronze.
With unprotected brass, bronze or copper, the patina process occurs more quickly. What happens to the metal finish over time? The answer to this question depends on whether or not a patina was applied artificially when the sink was made, the environmental factors present when in use, how much the product is used (wear) and the type of maintenance or care employed.
If you are purchasing a copper sink that has a finish (i.e. it isn't a “shiny copper”), heat and/or chemicals have been applied to accelerate the aging process. You will see such terms as “oil rubbed bronze” or “weathered copper”. To create these finishes, the metal has been exposed to a chemical bath and possibly heat as well, that reacts with the metal and changes the color. The darker the finish, the less the metal will patina or age after it's installed. In a way you are “shortcutting' the patina process. Regardless, you still have a living finish that will evolve, but generally speaking, the darker the patina is to start with, the slower the change over time.
Environmental factors specific to your home and chemicals that may be exposed to the surface of your sink are the great unknown. Every application and environment is different. Humidity, airborne salinity, pollutants and oxygen work together with time to coat the metal surfaces with a signature patina. If you have a kitchen copper sink and expose the metal surface to certain acids such as those found in a lemon, you will actually dissolve some of the patina. The constant changes due to these myriad factors are treasured by some and not welcomed by others. Personally I like the rich hues and earthy browns that occur over time. I see this as “character” and appreciate the uniqueness in color and tone between two identical products in different environments.
If you appreciate a living finish, the care and maintenance of your sink will be fairly straightforward. If you wish to prevent it, this is possible to a certain extent. There are several different ways you can slow down the patina process. Applying a brass or furniture wax that does not contain polish or cleaners can slow the change in patina much the same way an automotive wax protects the finish of your car. If desired, patina on a sink can be removed with a metal polish or mild acid such as lemon juice or vinegar. Waxing the surface will preserve the shine, or the sink can be left untreated to develop a new patina.
Oftentimes we sense that our customers are fearful of a living finish….or that this type of finish will require more maintenance. Our answer is always the same – if you don't like the patina that you eventually end up with, you can always start over! Any copper or brass cleaner will revert the patina back to a shiny surface if you like. If left unprotected, the aging process starts over again and within a few weeks you will begin seeing the metal surface darken. In addition, you can always buy a sink with a darker finish and keep the surface waxed. This will ensure the least amount of change over time. As for maintenance, occasional cleaning with soap and water is really all you need to do. If you opt to wax your sink, this is generally something you will need to do only every 3 – 6 months depending on the amount of use. You can read more about the care & maintenance of copper sinks at Copper Sinks Online.