Copper is a type of metal that has been around for thousands of years. You can find it on coins, pipes, cables for electrical wiring, and even decorative pieces. It’s a popular choice for a lot of reasons, but many people may be wondering if copper is capable of rusting.
Copper does not rust, as it doesn’t contain iron, and therefore is not capable of forming rust. Similar to other materials like brass, which also do not contain iron, copper can experience oxidation and corrosion, but rust will not form.
While rust and corrosion are not necessarily equivalent, we will discuss in this article how certain environmental factors and other elements can cause copper to corrode, as well as oxidize. We’ll be going in-depth into why copper can’t rust, how it’s affected by its environment, as well as how to successfully maintain and clean your copper made materials.
If you’re interested in learning more, keep on reading.
Why Copper Doesn’t Rust
As stated above, copper will simply not rust because it doesn’t contain iron. The only way metals are capable of rusting is if there is iron found within them. Materials with iron found inside will react by rusting when they come into contact with oxygen and water.
While copper doesn’t contain iron, it does contain elements that make it capable of oxidation and corrosion. Many people confuse the formation of rust and corrosion as the same thing, but they are different, and it mainly boils down to chemistry.
First, let’s break down the difference between rusting and corrosion.
Corrosion is the gradual breakdown of metals through a chemical reaction that is caused due to the environment the material is subjected to. Rusting is actually a form of corrosion, but iron oxidation is occurring when rusting occurs, also rusting cannot occur if there is no iron found within those materials.
Below, we’ll explore how and why copper can corrode and oxidize, as well as how you can treat the infected area.
Copper and Corrosion
Corrosion occurs on copper when it comes into contact with water.
When water meets copper, a blueish-green build-up called a patina can form on the surface. While visually, many people enjoy the look of a bright patina on surfaces like roofs and antique decor, they are definitely pros and cons of corrosion on copper.
For one, when patinas are formed on the copper surface, electrons are then lost from that metal. Yet, patinas can also serve as a positive, seeing how the built-up grime can protect the copper surface from being damaged by oxidation.
Copper and Oxidation
Oxidation occurs when a metal surface comes into contact with air.
Similar to the patina that is created when corrosion occurs, a brightly colored patina can also build up when copper is exposed to air. This in turn, also protects the metal from future corrosion, which is beneficial to the copper surface long term.
Yet, oxidation can also make copper unusable, and even dangerous. For example, when using a copper surface for cooking, when oxidation on that surface has already occurred, this can be potentially poisonous if it comes into contact with acidic foods.
Probably one of the most known outdoor sculptures, the Statue of Liberty, is a copper made piece that has a green patina over it.
So while oxidation and corrosion can have negative effects on some surfaces, copper can still have an iconic and beautiful look to it, even when surrounded and effected by outdoor elements. Unlike rust, which creates red-brown flakiness on the surface, that can visually damage the metal long term.
Hopefully now you have a better understanding of how copper may not be able to rust, but how factors like oxidation and corrosion can still occur. Below we’ll go into some of the ways you can treat copper that has been affected by outdoor elements.
How to Treat Tarnished Copper
Stated above, we discussed how oxidation and corrosion can affect the appearance and durability of copper. Below, we’ll explore some ways you can successfully treat the surface of copper that has been tarnished by other elements like water and air.
A copper polish will easily remove discoloration, tarnish, and restore shine. While some might be advertised as brass or copper polish, you can use most of these kinds of products on most metals.
The Weiman Brass and Copper Polish and Cleaner is a great choice, and will easily help you achieve the results you’re looking for. This product also promises a non-toxic, water-based, and scratch-resistant formula that won’t damage the surface of your copper materials.
It’s suggested you apply this polish to a clean, soft cloth and rinse off the product once you polish thoroughly. Lastly, dry and buff with a clean cloth to achieve a shiny surface.
Lemon Juice and Salt
If you’re looking for a way to use household products to clean your copper materials, this solution might be for you.
You can easily remove any kind of tarnish copper has on its surface in just a few easy steps. Squeeze a lemon into a bowl, followed by sprinkling in salt. It is recommended that you use a 75:25 ratio, with three times as much lemon to salt.
After you’ve stirred the mixture until the salt completely disappears, dip a soft cloth into the mixture and apply to a copper surface. If you don’t have lemons on hand, you can also use orange juice as it’s also acidic.
In this article, we have covered how copper is not capable of rusting, because it’s a metal that doesn’t contain iron.
We went over how while copper can’t rust, we touched on how copper can still oxidize and corrode. This happens when metals like copper come into contact with water and oxygen. This can affect the overall appearance of the surface, as well as other factors like strength and durability.
We also went into the multiple ways you can treat and clean tarnished copper. Hopefully, you now have a better understanding of how copper works and how you can get the best results.