What Causes Rust?
Updated: Apr. 17, 2024
Rust is a chemical reaction that can ruin your favorite tools and toys. But you can avoid it, and even reverse it.
What Causes Rust to Form?
Rust wreaks havoc on your bike, shower curtain rod and iron patio furniture. We know that unsightly and often messy reddish- or yellowish-brown flaky coating on some of our favorite metal kitchen, garden and workshop tools and toys all too well. But to really understand it and prevent it, you need to know the science of it.
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Oxidation Reaction
Rust results from a reaction called oxidation, in which iron reacts with water and oxygen to form hydrated iron (III) oxide. Essentially, the metal is naturally returning to its unrefined state. Learn how to remove rust with electrolysis.
Because iron and oxygen have opposite charges, they gravitate toward each other. But this results in iron losing electrons to oxygen atoms (oxidation), and the result is that flaky coating.
The process can be sped up various ways (and ones that you should learn to avoid!), like nature’s minerals, chemicals and temperature fluctuations. That’s why leaving a bike or gardening tools outside instead of in the garage is a bad idea.
How To Prevent Rust
Because allowing iron, water and oxygen to intermingle creates the unwanted reaction that can harm your stuff, the best way to prevent that is to keep them apart.
Keep your favorite metal stuff inside when not in use, and make sure it is completely dry when storing it away. Another tip: Use spray-on wax and oil coatings for your tools and toys. ( Find out how much time spray paint takes to dry).
Plus, here’s how to remove rust from concrete. We also have some bonus tips for you on prepping rusty metal for paint!
How To Reverse Rust Formation
If you do get rust on something, don’t fret just yet! You can reverse the reaction by using lemon juice (citric acid) or vinegar (acetic acid). (While you’re at it, also learn how to treat garage door rust.)
The Farmers’ Almanac also suggests using potatoes, especially for de-rusting your knives: “Sprinkle a little salt or baking soda onto the potato and then rub it over the rust spot, or just insert the knife into a potato and let it sit. The oxalic acid in the potato helps to dissolve the rust.”
Do you have rust spots on your car? Here’s how to repair rust on a car.
