Without proper maintenance and preventative care, everything from decorative indoor projects to vehicle parts are subject to rust damage. This can affect the overall look of your laser cut metal parts, but more importantly, damage the functionality of the part as well. It’s important to ensure your parts are ready to battle weathering, so keep reading to learn how to prevent rust on your metal parts.
What Exactly is Rust and What Causes Rust?
When iron is present in a metal, it’s considered “ferrous.” Many of the most commonly used metals are ferrous. Rust forms as iron oxidizes in the presence of air and water, which causes the metal to begin deteriorating and experiencing damage on several different levels. Since rust is an iron oxide, any ferrous metal can experience rusting.
Types of rust
There are 3 different kinds of rust that can occur depending on the conditions your metal is exposed to.
1. Red rust
Red rust is the most common type of rust and is the first stage in more severe rusting. This is the red-orange powder that forms on ferrous metals which worsens and begins to flake off after time. The red color itself is oxidized iron, so red rust only occurs in oxygen-rich environments.
2. Black rust
Black rust is less widely known than red rust but equally as important to the rusting process. Black rust is found underneath the outer layer of red rust, and is caused by iron oxidizing in an oxygen and moisture poor environment. Black rust is a thin film coating the metal beneath it, protecting the metal from further rust damage. Black rust does not propagate as quickly as red rust, so it takes more time for it to form.
3. White rust
White rust is as common as playground equipment. Many iron bolts and fixtures found in fencing materials and outdoor equipment will experience white rust at any given time. White rust only forms in the presence of zinc plating and feels powdery to the touch. It is easy enough to prevent with chrome coating.
Stages of rust
There are also several “stages” to rusting. Knowing the signs of rusting at these levels can help you prevent further damage to your parts.
Stage 1: Surface rust
Surface rust is the very beginning of iron oxidation. All ferrous metals will experience surface rust with enough time and exposure. Surface rust is a slight red or orange tinge to the edges or imperfections of your metal. At this point, there will be little to no flaking in the rust.
Stage 2: Bubble rust
Bubble rust is the next stage of iron oxidation. If the rust is not taken care of at the surface stage, it will begin to bubble and flake. The metal is not yet crumbling at this stage, but it has developed scales and the layers of rust can be easily removed with a wire brush.
Stage 3: Corrosion
Corrosion is the last stage of oxidation and at this point, the metal is completely deteriorating. The base metal will be flaking away, leaving irreparable imperfections and even holes in your part. The part may even crumble to the touch around the worst of the rusting. This stage of rusting is ultimately what we need to prevent and prepare for.
What Metal Doesn’t Rust? Corrosive vs. Anti-Corrosive Metals
We’ll get into some of the ways to prevent rusting on corrosive metals, but first the easiest way to prevent your parts and projects from rusting is by using anti-corrosive metals in their construction. Understanding the pros and cons of these materials and what makes them anti-corrosive is vital to your success in creating a rust-free part.
Anti-corrosive/rust proof metals
The most common anti-corrosive metal is aluminum. When exposed to water, aluminum creates an aluminum oxide layer, protecting itself from moisture and corrosion. It’s also lightweight, affordable, and easy to work with, making it a go-to option for parts of any kind.
If you need the strength of steel with the anti-corrosion properties of aluminum, laser cut G90 galvanized steel is the way to go. This carbon steel is coated with a zinc layer to protect it from rusting. As we know, zinc itself can also corrode, causing the zinc layer to disappear over time. Galvanized steel is perfect then for high-strength projects that experience little weathering since the protective coating doesn’t last forever.
Not all corrosion is bad! If your project is mostly decorative or has an electronics application, we recommend laser cut brass or copper. These materials are famous for their corrosion, yes, but they do not rust thanks to the lack of iron present in their chemical makeups. The patina which forms on both brass and copper is less destructive than rust and actually works to protect the material from further weathering. Although these aren’t the highest strength materials, they are lightweight and easy to manipulate.
Corrosive metals
As we already know, rust is just iron oxide so corrosive metals are any ferrous metals (contain iron). Some of the most common ferrous metals that we cut here at SendCutSend are 304 stainless steel and 316 stainless steel, as well as carbon (mild) steel and 4130 chromoly. The commonality between all these metals is their iron content.
Although the iron content can be seen as a weakness in these corrosive metals, it is also a key to the strength they can provide to your project. All these corrosive materials are some of the highest strength materials we offer and when it comes to strength, sometimes it’s best to sacrifice a bit of time and effort into preparing the metal for weathering rather than sacrifice in favor of a lower-strength, anti-corrosive material. With this in mind, let’s talk about how to prevent rusting in these materials so you can get the full benefit of using them in your next project.
8 Ways to Prevent and Stop Rust on Metal
There are some features you can look for in the metal you order to make sure they’re already prepared for weathering and rust prevention, and there are a few processes you can do yourself to protect your parts from rusting.
Powder coating is one of the best ways to prevent rusting on ferrous metals by adding a protective hardened polymer layer to the surface of your part. This doubles as an aesthetic choice with seven different powder coating colors available in house here at SendCutSend. You can learn how to optimize your parts for powder coating here.
- Plating or Galvanizing
Plating is the process of coating your metal parts in a protective metal layer in either zinc or nickel. We have two ferrous materials available for zinc plating: mild steel and 4130 chromoly. We also have nickel plating options available for mild steel and copper. As we mentioned, metal plating such as zinc can wear away after time so be prepared to maintain your parts to prevent rust even with metal plating.
A similar option would be to opt for galvanized steel in your project. Galvanizing is another process of adding zinc to iron or steel to help prevent rust, and luckily, we offer laser cut galvanized steel right here.
- Oil
An oil coating will help keep oxygen and moisture from reaching the surface of your part, preventing iron oxidation. It’s a relatively affordable and simple solution, but it will need to be closely monitored and your parts may need oil reapplications frequently.
- Dry coating
Dry coating is similar to oiling except it dries to the touch and leaves a clear, protective coating behind. There are several different dry coating options, like this one from Armor. Dry coating is more environmentally conscious than oiling and is meant solely for ferrous metals.
- Rust-prevention paint
A few coats of rust-preventing spray paint will do wonders for your ferrous parts. Rust-prevention paint is similar to powder coating in that it literally provides a wall between your part and the elements which is difficult to damage or wear. Most companies that offer a rust-preventing paint also offer a clear coat version so there’s no need to change the aesthetics of your part.
- Find the right storage
Storing your ferrous metal parts away from moisture and oxygen-rich environments is one of the best ways to ensure their longevity. If possible, keep an air-tight seal on these parts and store them in a cool, dry place.
- Careful handling to prevent scratching
When ferrous metals are scratched or dented, it exposes more metal beneath the surface layer and causes moisture retention. This can speed up the rusting process. Handling your parts with care and making sure non-protected parts are used in low-stress environments will slow down the rusting process.
- Regular maintenance and early repairs
No matter what coating or protection process you use, keeping up regular maintenance on your metal parts will always be the best way to keep rust from forming or to catch rust early before it causes damage. In the early stages of rust, use a sander or wire brush to scrape away the damage. Then apply a protective coating like oil or dry coat and seal it in with rust-preventing paint/clear coat. Catching the early stages will prevent long-term irreparable damage to your parts.
FAQs About Rust Prevention
Yes! If caught in the early stages of rusting, it’s relatively simple to stop rust and prevent it from spreading. All you need to do is sand away the areas affected by rust (you may need to use a wire brush if the rust has begun to cause scaling), apply a protective coating like oil or dry coat, and then seal the area in with a rust-preventing paint or clear coat. Apply these coatings to the areas around the one affected by rust to ensure maximum coverage.
The easiest way to remove rust from metal is with an orbital sander or a piece of sandpaper if you need more precision. For a more aggressive removal technique, use a wire brush.
The best way to keep metal parts from rusting is to use anti-corrosion metals such as aluminum or galvanized steel. If you must use corrosive metals, you will need to apply a protective coating like powder coating or plating to prevent rusting.
Prevent Metal Corrosion in Your Laser Cut Parts
The key things to consider in order to prevent metal from corroding are preventative care and protective coatings. Our services like powder coating and plating can help you get one step closer to rust-free parts!
Be sure to check out our blog for more information on caring for your laser cut metal parts.
