Rust is formed when iron – which is the base metal of steel – is exposed to too much air and moisture. The official term is oxidation, and it occurs when the surrounding air oxidizes iron molecules. It can typically be seen as a red-brown stain on the exterior of the metal, which can go on to stain surfaces into which it comes into contact.
These surfaces can include tools, household fixtures, and any chrome found on cars and bikes. These stains are not always easy to remove and often require the assistance of chemical intervention.
Some rust stains are mild enough that a little elbow grease and hot soapy water, or bleach, will be enough to lift them. In these cases, the stains are usually superficial and have not been present long. However, you will likely need to use an abrasive scrubber and a mixture of substances for deep-set rust stains.
The most common types of rust removers include:
- Chemical removers
- Chelating Agents
- Rust Converters
Depending on the surface, each of these will work differently, and one or more may not be suitable. Always check the label to be sure the rust remover includes the desired surface within the description.
Chemical rust removers are usually made from commercial-grade chemicals. Within this type of rust remover, there are three common types of chemical used:
- Acids such as nitric acid, hydrochloric acid, acetic acid (white vinegar), sulfuric acid, oxalic acid, muriatic acid, and citric acid.
- Petroleum-based solvents like those found in standard household products such as WD-40.
- Sodium hydrosulfite is a powdered rust remover.
Acidic rust removers will need to be diluted to at least 30% with water and should only be used outdoors or in well-ventilated areas when wearing a mask and protective gear. Though these kinds of rust removers are effective within minutes, they can also cause damage to the surface. This kind of rust remover is not recommended for use on cement due to its corrosive nature.
Both petroleum-based solvents and sodium hydrosulfite have been known to be successful in removing rust from cement. The latter of which can start to work within the first five to 30 minutes, where petroleum-based solvents will need at least a day to take full effect.
Chelating agents are organic compounds. Such rust removers are non-toxic, acid-free, and mostly eco-friendly. They work by binding with the iron molecules in the rust to make them water-soluble. The stain needs to be soaked for at least 30 minutes for the process to be successful, though it could require an overnight soak.
Rust converters are typically used when the amount of rust is too much to try to remove. Instead, this product will convert the existing rust into a stable coating that protects the surface and allows for paint to cover the area. This is mostly only used for iron or steel objects that will be repainted, such as garden furniture.
Whether the rust stain is mild or extensive, several different methods and products can eradicate the stain. A less potent approach will likely be effective for newer stains, and you can avoid harsh chemicals. However, for set-in stains, you will need something more robust.
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