Copper gutters look incredible when they’re polished and new. Some copper gutters look incredible after years of service. Compare the two side by side and you might not even realize they were made of the same stuff. The reason for that, is the patina.
When copper is exposed to the elements, some interesting things start to happen. The outside layer of the metal begins to react due to oxidation, and a thin layer or coating forms over the outside surface. This layer actually protects the copper from the damaging elements, making copper gutters a fantastic long term building material.
Because the patina is formed naturally by the local atmospheric conditions, no patina looks exactly like the other. However, there are a few tricks that homeowners can use to speed up, or otherwise affect, the patina of their home gutters.
Darkening the Patina
Liver of Sulfur is typically used to darken copper patina’s chemically. It is composed of potassium sulfide, polysulfide, potassium thiosulfate, potassium bisulfide, and probably some other potasses and sulfizzes too. Depending on how much you use, the copper will darken into a light gray-blue or a dark brown/black.
Pop Quiz: What colour was the Statue of Liberty in 1886?
Answer: No idea, but it probably wasn’t green.
The famous Statue of Liberty is well known for its shimmering green. This color is actually a patina effect called “verdigris”, and is developed over several years of time. If you don’t have the centuries to wait, there is a cheap chemical alternative. Horse urine has been used for centuries as a quickener for developing a green patina on copper. Believe it or not, the stuff works; and yes, we have our sources.
If you have questions about changing the patina on your copper gutters, call one of our friendly gutter guys for a consult.