Absolutely not! There are some companies out there that give the impression that just because we suggest wax with our sinks that you HAVE to do this.
It couldn’t be further from the truth. We would say about 60% of our customers wax their copper sinks on a regular basis and the other 40% do absolutely nothing. Regardless if you’re dealing with recycled or virgin copper, copper has a living finish that will change color and develop patina over time. Waxing your copper sink just simply helps to slow down the aging process.
By waxing a copper sink, you’re preventing oxygen from getting to the metal. Oxidation is what develops patina on copper, and after about 15 to 25 years, weathered patina (outdoors) can turn light green, called verdigris patina, like on the Statue of Liberty. Patina actually protects copper, but some people don’t like the variations in color change. So, waxing your copper sink creates a thin, protective barrier to elements that come in to contact with copper, to minimize unwanted color changes during the natural patina process. Like waxing a car or boat, you are helping the finish last longer than left untreated. It also helps reduce water spots if your water has a high mineral content, or calcium build-up from hard water. We sell the Renaissance Wax, which is a microcrystalline wax, but you can also use a carnauba wax.
Weathered Copper Patina Chart
Waxing seems to be more popular with our Dark Smoke and Rio Grande finishes, because these are darker than new copper and as they patina they actually lighten over time.
Dark Smoke finish
Rio Grande finish
Waxing these darker colors helps to slow down the patina and lengthen that person’s preferred choice of copper finish. Regardless of what finish you choose for your sink, waxed or not waxed, you will see your copper sink change color.
The environment copper is in and how it’s used will also affect how it ages. Wet copper will age faster than dry and copper exposed to salt water or salt air will also patina very differently. Copper will also react with certain chemicals, such as bleach, which will lighten the color. It doesn’t harm the metal but it may turn it a color you weren’t expecting. If you are familiar with copper pots, spots and color changes occur but don’t stay that way for long. The copper will naturally keep changing color.
Be careful with anyone that tells you their copper sink doesn’t need wax because it won’t change color, or the patina won’t change and won’t be affected by food or chemicals. In this case, maybe the copper isn’t 99% pure, or some other treatment is applied on the surface of the copper. Some companies will apply a lacquer finish to their copper to prevent it from changing color. Lacquer is problematic, because over time the lacquer coating peals or blisters uncontrollably, leaving certain areas exposed and others covered. The lacquer bubbles and blisters can also trap particles of substances from water and food, which creates further unwanted spots of color changes.
In the end, waxing copper is an option and a personal preference. Everyone is different and so is the way they maintain their copper sink.