Chemicals Used to Remove Rust & Corrosion

Rust and corrosion can destroy practically anything made of metal, from metal roofs to faucets to outdoor tools. Luckily, certain products and DIY cleaners can help remove rust and corrosion from surfaces in and around your home. These include citric acid, Naval Jelly, muriatic acid and vinegar and salt. Some of these chemicals are stronger than others, so knowing how to best use each one is essential.

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Chemicals Used to Remove Rust & Corrosion

What is Rust and Corrosion?

Corrosion refers to the deterioration of any metal due to the metal's interaction with an outside substance, most commonly oxygen. When oxygen causes metal to corrode, it's called oxidation. In oxidation, oxygen molecules combine with molecules in the metal to create oxides, which are far weaker than the original refined metal. Only oxygen can cause oxidation, but metals can corrode from contact with other outside substances as well, such as water, acids, bases, salts and oils.

Rust is a type of corrosion. Specifically, it's the process of corrosion in metals that contain iron. When iron oxidizes, it forms the red, flaky substance commonly referred to as rust.

Citric Acid

Citric acid is a naturally occurring acid found in citrus fruits, such as lemons, limes and grapefruits. It can also be used to dissolve rust from small metal objects, such as tools or bike parts. Citric acid may be a great choice to remove rust or corrosion if you're looking for something inexpensive, readily available and gentle that won't remove painted finishes. Citric acid can also be safely poured down sink drains since it's completely biodegradable.

Citric acid can be purchased in two forms. Many grocery stores sell it as a powder (usually in the baking section) or you may choose to simply buy a piece of fruit containing citric acid. Lemons work especially well for removing rust since they contain the most citric acid of any fruit.

To dissolve rust or corrosion, first fill a plastic tub with water. Be sure the tub is large enough to fit the metal object you wish to clean. Add one tablespoon of citric acid powder or half of a sliced lemon to the water, then add the object you wish to clean. With a scouring pad, gently scrub the object, then let it sit for around 30 minutes before scrubbing again. Repeat for around two hours or until the object is free of visible rust or corrosion.

Naval Jelly

Naval Jelly is a popular rust-removal product from Loctite, a company that specializes in sealants, adhesives and surface treatments. As its name suggests, Naval Jelly isn't a liquid but a gel, which makes it less likely to drip or spill during use.

Phosphoric acid forms the base of Naval Jelly's formula. This acid is powerful enough to remove paint and can even burn human skin, so be sure to use rubber gloves when working with Naval Jelly and keep it away from painted surfaces. Be sure to use Naval Jelly in a well-ventilated area since phosphoric acid can be harmful if inhaled over a long period of time.

To use Naval Jelly, simply brush it onto a rusted or corroded metal surface, wait between five and 10 minutes and rinse clean with water. Naval Jelly shouldn't be left on any surface longer than 15 minutes.

Muriatic Acid

Muriatic acid is a powerful chemical used for etching concrete, lowering the pH balance of pool water and removing rust and corrosion from metal. Muriatic acid can be purchased from several popular brands, including Klean Strip and Jasco.

Muriatic acid is very similar in composition to hydrochloric acid, or HCL. In fact, the two acids are practically the same, the only difference being that muriatic acid contains impurities. Most of these impurities were purposefully added to increase the acid's potency. HCL is already a strong acid (in fact, it helps dissolve food in human stomachs) so it goes without saying that muriatic acid is powerful as well. Always take the necessary safety precautions when working with muriatic acid by wearing rubber gloves and simple face masks, and working in a well-ventilated area.

Muriatic acid is best used only on stainless steel, as it can cause rapid oxidation in other metals. To use muriatic acid, brush it onto a metal surface, scrub gently, then neutralize the acid with baking soda as soon as the visible rust is gone.

Vinegar and Salt

Citric acid isn't the only rust remover you can make yourself. Vinegar and salt also make a good solution for cleaning rust from small metal objects. This is because vinegar (usually used for food preparation) is a mild acid, and its acidity increases when salt is added to it.

To remove rust with vinegar and salt, place the rusted objects in a plastic tub and fill the tub with white vinegar. Add one cup of salt for every gallon of vinegar, stir gently and leave for around 12 hours or until all visible rust is gone.

Unlike many store-bought rust removers, vinegar and salt aren't harmful to humans. This means that no safety equipment is necessary when working with them. They can also be safely washed down the drain.