How to Prevent Corrosion & Keep Metal Beautiful
June 19, 2015 by Joe Ness
Photo: Abby Lanes on Flickr
Metals are amazing materials. They can be strong, flexible, beautiful, and versatile. But if neglected, improperly treated, or exposed to the elements, they can also be surprisingly fragile. Especially when it comes to corrosion.
What is corrosion? Why do metals corrode? Can anything be done to prevent corrosion? What can you do to keep metal beautiful?
Let’s find out.
Where Does Metal Come From?
Seems like a simple question, right? You dig it up out of the ground!
However, most metals that are used for industrial and commercial applications (think metal beams, building materials, architectural decor, furniture, fences, etc.) don’t come out of the ground ready to use.
In fact, only copper, gold, platinum and a few other precious metals don’t need much processing before use. Steel, for example, is a highly refined and processed alloy of iron ore, carbon, and other metals.
But what does this have to do with corrosion?
Photo: Per on Flickr
What is Corrosion?
Let’s think about bread. A baker starts with wheat that was grown, harvested, and processed into flour. Then the flour is combined with yeast, salt, and water and then baked to make a loaf of bread.
If you leave your bread sitting on the counter too long, or let it get too damp, it’ll start to grow mold right? But the wheat itself, before it’s harvested doesn’t grow mold in the same way. What gives? The wheat is stable and resistant to mold. The bread, much less so.
Have you figured it out yet? Raw metal ore is like the wheat: stable and resistant to corrosion. The alloy or processed metal doesn’t have that same stability and resistance to mold– I mean corrosion.
Alloys and processed metals are unstable. Chemically speaking, they want to revert back to a more stable state. This is the process we call corrosion.
The Most Famous Corrosion in America
It’s sitting right there in New York Harbor. That’s right: the Statue of Liberty!
When first installed, she was bright and shiny, like a new copper penny.
It took about 25 years, but then her copper skin (about 1/16” thick) corroded and became the green patina we know today. It doesn’t affect her structural integrity though. Beneath that thin copper layer, she’s made from cast iron and stainless steel.
Photo: Sue Waters on Flickr
The Corrosion We See Everyday
Rust. It’s everywhere. Iron based metals, including steel are very susceptible to rust, unless treated or protected in some way, which we’ll talk about later on in this article.
Rust can be real trouble. It weakens metal and can do more than create an unsightly appearance. Cars, buildings, tools and anything with iron or steel is susceptible to rust.
A home or office building with rusting support beams, or a car with a rusty frame is weak and could fail in a very dangerous way. Luckily, protective coatings and the use of stainless steel can reduce the damage that rust can do.
What Causes Corrosion?
Why does iron rust? Why does copper turn green? What causes corrosion? Corrosion happens when metal is exposed to one or more of the following:
Even exposure to the air alone can be enough to corrode some metals, like steel. That’s because in all but the very driest climates, there’s enough moisture in the air to accelerate the process of corrosion.
Do you wonder why metal rusts faster in saltwater or near the ocean? An electric current is just an orderly flow of electrons. And electrons move more easily in salt water, or in salty air near the ocean. It’s this electric current that speeds up the formation of corrosion and rust.
Other compounds found in water (minerals in hard water or acid rain) can also affect the rates at which metals corrode.
How to Prevent Corrosion Before it Starts
What’s the best method to prevent corrosion? It starts with choosing the right metal. A metal’s corrosion resistance depends on its chemical makeup as well as whether a protective or decorative coating has been applied.
At Cascade Coil, our materials balance corrosion resistance with other features including appearance, strength, versatility, and ease of use..
Basic Steel – Strong, low cost, and easily painted to add corrosion resistance.
Aluminum – Highly corrosion resistant, lighter than steel, and easy to work with.
Nickel-plated Steel – Bright, shiny, and much more resistant to corrosion than unplated steel.
Galvanized Steel – A thin coating of zinc atop of the steel makes it very corrosion resistant. Best for industrial uses where high strength is needed.
Copper-clad Steel – 100% copper applied to a steel base. Will stay a bright and shiny red if lacquered, but will oxidize to deep brown and green if left untreated.
Stainless Steel – The use of different metals in stainless steel alloys offer varying levels of corrosion protection, strength, and flexibility.
Titanium – Incredibly lightweight and highly corrosion resistant, but less versatile than other metals.
Nylobind Steel – Steel coated with flexible, plant-based, and environmentally-friendly plastic. Waterproof, abrasion resistant and available in a variety of colors.
Let the project you’re working on dictate your choice of metal. Anything that’s bound to get wet, coiled wire fabric shower curtains or outdoor furniture for example, needs to be very corrosion resistant. When using metals decoratively indoors, aesthetics may matter more than corrosion protection.
Keeping Corrosion at Bay & Keeping Metal Beautiful
But what if you’ve already bought a piece of metal patio furniture or a fence or you’re worried about rust forming on your car? What can you do to reduce corrosion and keep your metal beautiful?
Protect metal from the elements as much as possible. Move patio furniture into a dry garage when it’s not in use. And make sure to keep your metal clean. Even an occasional gentle scrub can help prevent rust and corrosion. If you drive your car on the beach, rinse it with fresh water and dry it thoroughly shortly afterwards. This goes for anything that’s exposed to salt water, like fishing reels and outboard motors.
Also avoid damaging paint or other protective coatings. Even a small chip or ding can let corrosion take root and cause serious damage that you wont’ notice until it’s too late.
Photo: Josh Larios on Flickr
If you do see the first signs of corrosion like little spots of rust, you’ve still got time to act. Fine sandpaper can remove surface rust. Then rust-proof paint can be used to protect the spot. More advanced corrosion may require buffing with a wire brush or dremel tool before refinishing. Household chemicals, like white vinegar can cause a chemical reaction that can remove rust, too!
Make sure to use proper safety precautions and use protective gear to protect your eyes and lungs whenever removing rust and corrosion.
The Final Word on Corrosion
Corrosion is a natural process that people have been fighting for as long as we’ve been using metal. By choosing the right material for your project, properly caring for the metal you choose, and taking early action if corrosion starts, you’ll have no trouble keeping your metal corrosion-free and beautiful for years to come.
Want to learn more about our corrosion-resistant metal products? Contact us today.