What Is a Rust Converter?
Rust converters are agents that convert red rust to black rust and inhibit the progress of rust.
Red rust is the reddish-brown color commonly known as rust, and if left unchecked, rust will spread and corrode to rags. On the other hand, black rust is an oxide film that forms on the surface of iron and stops the progress of rust.
Usually, there are treatment methods such as “polishing with sandpaper” or “removing rust with a rust remover,” both of which are labor-intensive methods. Rust converters can be applied directly to the rust with a brush to change the red rust to black rust and prevent the rust from progressing.
Uses of Rust Converters
Rust converters are used in areas prone to rust because of their role in inhibiting the progress of rust. It is especially applied when it is difficult to remove rust by polishing. For example, it can be used on large objects such as automobiles, motorcycles, and outdoor fences.
Other than that, it is suitable for rust treatment on tanks, bridges, agricultural machinery, railroads, ships, gates, steel stairs, shutters, and other areas where rust is difficult to remove. However, since rust converters will look black with black rust after application, they are used in areas that are difficult to see or where the appearance is not a concern.
Principle of Rust Converters
Rust caused by wind, rain, and humidity is red rust. When red rust occurs, the surface becomes wavy, allowing moisture and oxygen to penetrate between the waves, and if left unchecked, further corrosion can progress to the point where the metal is torn to shreds.
Rust converters contain chemicals that are effective against red rust and react with air, chemicals, and water to turn the rust into black rust. Black rust is rust that occurs when steel is heated to high temperatures. Unlike red rust, black rust is impervious to oxygen and water.
Rust converters can prevent steel corrosion, but they cannot remove the rust itself. It only changes the composition of the rust and prevents it from getting worse. To remove rust, use a rust remover or rust removal cream. Rust converters will turn black and should not be used on visible areas.
Oil-based rust converters have a chemical-like odor, which can be strong if used in an enclosed space. There is a risk of ignition in a fire-hazardous area, and work should be performed in a well-ventilated environment or outdoors.
Structure of Rust Converters
When metal atoms on the surface of metal undergo a redox reaction with moisture and oxygen, rust is formed as a corrosive substance. There are two types of rust: red rust and black rust. Rust converters chemically change red rust to black rust.
1. Red Rust
Red rust is iron hydroxide or ferric oxide, which is formed when iron atoms naturally combine with water and oxygen. Red rust is water-soluble and easily retains moisture, and once red rust is formed, the reaction proceeds one after another.
2. Black Rust
Black rust refers to ferric tetroxide. Because of its high density, black rust is hard to adhere to the surface and the reaction does not progress to the interior. Black rust can be obtained by heating iron.
Types of Rust Converters
There are two types of rust converters: oil-based and water-based.
1. Oil-Based Rust Converters
It forms a durable and strong film and is suitable for outdoor areas of buildings and exterior surfaces of vehicles. It does not change with weather conditions and can cover rusted areas with a thin film, which keeps its effect for a long time.
However, because it is oil-based, it cannot be handled in areas where fire is present.
2. Water-Based Rust Converters
Because water-based products are easy to penetrate, they can soak in and reach areas that are difficult to reach with oil-based products. It is easy to apply on uneven surfaces.
It forms a film in a short time and dries relatively quickly. It has little odor and does not require special care with fire.
How to Select Rust Converters
Rust converters have a strong odor and require ventilation. There is also a high risk of ignition, so apply with care. There are two types of rust-converting agents depending on the form of application: brush/roller application type and spray type.
The brush/roller type is suitable when applied to large areas such as fences and gates, while the spray type is easier to use in hard-to-reach areas such as narrow or intricate places. In addition, there are various other types of products, such as those that contain rust-inhibiting ingredients and those that cannot be painted over (they will melt if painted over). It is important to choose the rust converters that best suit your application.