How to Prevent Metal Items from Rusting in Storage

Rust is a major problem that affects items made of metals, including vehicles, machines, equipment, appliances, electronics, gadgets, jewellery, coins and medals. In order to keep your possessions free of rust, you need to understand the science behind it.

Rust refers to the corrosion of metallic materials. It is a natural reaction of iron, copper, and other oxidisable metals to the oxygen present in the air and water. Rust or iron oxide needs oxygen, water or air, and metal.

Rusts are not always red-orange-brown. They appear green in copper, grey in aluminium, yellow in iron-oxide-hydroxide (high moisture), black in iron oxide with low oxygen, and brown in high moisture but low oxygen. Allowing rust to spread could ruin your investments in metallic collections and tools. By preventing them from rusting with home and anti-rusts treatments, you can extend their serviceable lifespan.

Here’s how to prevent rust from forming:

1. Apply alloying method

This prevents rust by combining a corrosion-resistant metal with a rust susceptible metal. Example: Copper + Zinc = Brass.

2. Treat it with the cathodic method

This involves using a sacrificial anode or a metal that can easily give electrons compared to iron. The sacrificial anode metal, immersed in the electrolytic solution, sacrifices itself or corrodes itself to give metallic ions to the cathode, or the receiving metal. Such sacrificial anode metal includes aluminium, magnesium, and zinc.

3. Design with water in mind

This tactic involves material and engineering techniques to prevent the build-up of water. For example, an engineer could design a drainage system or downspout to prevent rainwater from stagnating.

4. Control the chemicals in the environment

You can reduce or prevent corrosion by removing the chemical sources that help form formic acid—a copper-corrosive chemical. In the case of the copper tubing in HVAC systems such as window-type air conditioners, remove sources that raise the formic acid levels such as fabric softeners, laundry detergents, body wash, and paint removers. Control the level of sulphur, oxygen and chloride present in your kitchen or laundry room.

5. Employ a preventive coating

Invest in paints, lubricants and sprays. For galvanised roofing, use primer paint for an initial coatinging and finish it with a final coating of latex or acrylic paint. You can use red oxides, magnesium-rich paints, zinc chromate, vinyl resin, chlorinated rubber resin, silicone aluminium paints, Polyurethane resins, binders, epoxy resins, coal tar epoxy and zinc chromate.

6. Observe preventive maintenance techniques

Without constant maintenance, any coating or paint is not enough. Scratches and dents can hasten rusting. Be sure to set up an organised storage space for metal items such as bicycle parts, pots, and pans. Unorganised or jumbled storage is an easy way to leave dents in your metallic items. For coins and medals, invest in protective plastic boxes to keep their lustre and shine.

Home methods vs products you can purchase in stores

There are also homemade methods and commercial solutions in the market that you can use to prevent rust.

1. Apply grease and oil

Use cooking oil or motor grease as a protective coating.

2. Treat it with paint

Coat a metallic surface with enamel or non-water-based paint. Use paint to prevent pitting or corrosion at the microscopic scale. If left unchecked, pitting can lead to large-scale rusting.

3. Store metals in a cool dry place

Store metals in a safe and dry environment. You can use silica gel or packets as desiccants to store lustre-sensitive items such as coins and medals. For large scale storage, use a temperature-controlled storage system.

4. Minimise crevice corrosion

When there’s a large gap between two metal objects such as screws and metal surfaces, fluid can enter this space. There’s actually a type of grease that is especially-formulated to prevent rust. Anti-rusts products fall into these different types: c1 for very low corrosion, c2 for low, c3 for moderate, c4 for high and c5 for very high.

5. Work with anti-rust lubricants and sprays

This is especially effective for coating tight gaps between screws and contact metal plates. Anti-rust lubricants contain rust inhibitors, oil, or some volatile ingredients with waterproof properties.

6. Treat it with barrier pigment  

Usually made from micaceous Iron oxide (MIO) and leafing aluminium, barrier pigments can coat or leave barrier coating on any smooth or irregularly shaped metal.

7. Choose anti-corrosion paint

Anti-corrosion paint contains zinc-rich epoxy with 90% zinc, inorganic zinc silicate and self-curing ingredients. These are categorised into C1-C4. Examples are alkyd and enamel paints.

8. Apply polyurethane coating  

Made from isocyanates and hydroxyl compounds, polyurethane coating requires curing time but is resistant to chemical and water.

9. Use zinc phosphate

It is an anti-corrosive pigment that is usually added to binders or paints.

How can Spacer help?

Spacer can help you find a safe storage space for your valuables whether it’s a rare coin, trophy, medal, or plaque collection. Through its online database, an interactive map, and direct contact with space owners, you can save time and money.