Which metals don’t rust?
Whether you’re using metal in the great outdoors or inside your home, the last thing you want it to do is rust. Although rusting is a relatively slow process, it can eventually lead to the complete disintegration of the affected metal. So, aside from looking unsightly, rust can also affect structure and performance. Some metals very obviously don’t rust, namely those used in precious jewellery: gold, silver, platinum and titanium, but you’re highly unlikely to be using those in construction or DIY. Here’s our expert guide on which sheet metal to choose when no rust is a must.
First up: what is rust?
Rusting happens when iron and some metals containing iron are oxidised, a chemical reaction which occurs when a material is exposed to water and oxygen. The resulting brown, flaky coating on the surface of metal not only looks untidy, but can eventually lead to total corrosion. That’s why it’s important to choose the right metal when you’re working on an outdoor project, or any application where the metal is going to be exposed to moisture.
OK, but which metals don’t rust?
Simply put, metals that don’t contain iron won’t rust, but there’s a bit more to it than that. Some iron alloys (metals containing iron), such as certain types of steel, have been specially-developed to be resistant to rust. The following metals won’t rust when they come into contact with moisture, be it from wind and rain in the great outdoors or in bathrooms and kitchens inside.
Aluminium doesn’t contain iron, so it doesn’t rust. Not only that, when aluminium is exposed to water, it develops a thin outer layer called aluminium oxide which actually makes the metal even more resistant to the elements. Aluminium corrosion does exist, but only when the metal is exposed to very alkaline or acid substances.
Brass is an alloy of copper and zinc, which means it won’t rust. No wonder, then, that it has been used on boats for hundreds of years. With its golden good looks, brass makes a striking finish in stylish bathrooms and kitchens, where aesthetics are as important as performance. Brass splashbacks are a particularly effective way to protect kitchen walls from steam and splashes. If you’re looking for brass with an interesting texture and patina, check out these aged brass sheets, which add instant vintage glamour to interiors.
Copper won’t rust because again, it doesn’t contain iron. It is a native metal, which means it can be found in its raw natural state, and doesn’t need to be extracted from an ore or combined with another element to be made. These qualities and its unique bright colour make copper a clever choice for moisture-heavy interiors, such as bathtubs and bar-tops. Just like with brass, copper splashbacks make an impactful statement in kitchens, as well as protecting paintwork. Although it won’t rust, copper exposed to the elements will develop a green coating known as a patina. Just like aluminium oxide, this patina actually protects the copper beneath it from damage. Sometimes people want their copper to come with a patina because the colours are interesting or they’re looking for an antique aesthetic, and this is where pre-aged copper sheets come in.
Although steel does contain iron, stainless steel comes with added chromium, which makes it ultra-resilient when it comes to moisture. Think about it: stainless steel is used in cutlery and kitchens, so it has to be rust resistant. This is why stainless steel splashbacks are another strong option for kitchens. The chromium that is added to the steel oxidises more quickly than iron, producing chromium oxide, which protects the steel and stops it from rusting. Stainless steel is often used in outdoor spaces, for example for bins and handrails, proof it really is resistant to the elements.