Rust can be a real nightmare on your metalwork and can ruin the look of items in and around your home. A fresh coat of paint can usually bring these types of items back to life, but it’s difficult to know if you can spray paint over rust.
Spray paint can be expensive, and the last thing you want to do is waste your time and money. But don't worry, because, in this guide, we'll explain whether spray paint works over rust and how to use it effectively.
Rust is a problem, but you can paint over it. However, you will struggle if you're using traditional paint. Brushing it onto rust can take a lot of time, and it's difficult to apply to an uneven surface. The dispersal method used with spray paint makes it much better suited for painting over rust because the aerosol paint can cover the uneven rusty metal more easily.
Aerosol paint, commonly known as spray paint, is paint that is stored in an air-tight pressurized can. There's a nozzle and a button on the top to release the paint through it. When the button is pressed, the liquid paint is so pressurized that it changes into a gas and is dispersed directly onto the surface in front. When it lands, it becomes liquid again, covering the surface in paint.
Spray paint is used because it gives a more even coat of paint compared to traditional brush painting, and it is much more time effective. This makes it perfect for painting large areas quickly, and it's often used in DIY jobs. There are a few different types of spray paint, but they can typically all be used on wood, metal, plastic, glass, and vinyl, making them a great multi-purpose paint for DIY projects. Many homeowners use spray paint on old items or furniture to refresh their look and keep them current.
Spray paint will adhere to rusty surfaces fine, so it can be used to cover up the rust and effectively hide it from view. It should only take one coat, but you may need to go over some of the worst affected areas. For best results, you're best to do some preparatory work before you spray paint. You should start by using soap and water to clean the metal surface and then use a wire brush to scrape away as much of the rust as possible. This will help the spray paint apply evenly to the surface of the metal.
It's worth noting that spray paint won't treat rust; it will just cover it up. Rust occurs when acidic substances, including water, come into contact with metals, and unfortunately, applying a new coat of paint won't reverse the issue. However, there is a common misconception that rust will spread across metal like an infection. This isn’t the case, and it only really happens when water meets oxygen, so the layer of paint can actually provide some protection from rust occurring in the future.
Many major spray paint brands, like Rust-Oleum, recommend that you apply a primer to the rusty surface before you spray paint it. This gives you greater protection against rust in the future and helps the spray paint to stick evenly over the metal.
Spray paint is commonly used on old outdoor furniture, metal structures like sheds or mailboxes, greenhouses, railings, and sometimes old cars. However, if you use spray paint on galvanized metals, then it can actually cause them to rust (which is ironic because galvanized metal is designed not to rust). This type of metal is commonly used for ladders, pipes, nuts, and bolts but probably isn't used for many items you'll be painting.
Rust-Oleum and other brands offer some specialist rust spray paints, but the most standard spray paints will work fine on rusty metal.
How To Spray Paint Rusty Surfaces (Detailed Guide)
If you’re spray painting over rusty surfaces, you’ll need:
Once you have all of the above, you should follow these steps:
1. Clean The Metal
Once you’ve identified the metal you're going to be painting, you should use soap and water to clean it down. This will help to remove any dirt and loose debris and leave you with a more even surface.
2. Remove The Rust
Use the wire brush to remove some of the larger pieces of rust on the surface of the metal. Make sure you brush this up because it could cause staining.
3. Sand It Down
Use the sanding brush to smooth the metal down as much as possible. This should help the spray paint apply evenly and remove rust that could stain the paint.
4. Apply The Primer
Take the primer and paint a coat on the surface of the metal. This will help stop any rust forming in the future and provide an even base for the spray paint. Leave to dry (usually, this takes 1-2 hours, but make sure you read the product instructions).
5. Paint The Metal
Hold the spray paint can roughly 8-12 inches from the surface of the metal and apply it evenly. Make sure you’re wearing your gloves and eye protection to do this safely. Leave to dry.
6. Check The Metal
Check the metal thoroughly and make sure you’ve got an even coat of paint covering the rust. You may need to go over it again in places or apply a second coat. Once you’re happy, leave it to dry, and you should be done.
Spray painting is usually fairly straightforward, but take it slow to avoid getting it all over you. We’d recommend choosing a darker color because the rust can stain if it’s too light. To spray paint safely, you should always do it outside or in a well-ventilated area because inhaling the fumes can be hazardous.
Safety Reminders & Important Tips
Safety comes first, and it’s important that you only ever use spray paint in a well-ventilated area. Some spray paints can be hazardous, so it’s important that you wear protective gloves and eye protection to keep yourself safe throughout the project. If you're painting anything electric, make sure it's all turned off, and try to keep the paint on the metal surface, not on you.
Cleaning the metal, removing the rust, and applying a primer will help the spray paint stick to the surface. This is what will give you an even coat, and it’s really worth taking the time to do all this prep work. Make sure you shake the can well, and apply thin, even coats for the best results. The layer of paint should last 3-10 years, but you can also apply a protective topcoat so that it lasts longer.
Remember that spray paint will work on a layer of rust, but if your metal is completely corroded, then paint isn't going to save it. At a certain point, the metal is too rusty, so don’t waste your time and effort and just throw it away.
Painting Rusty Surface FAQs
Will painting over rust stop more rust from developing?
Not directly, no. The paint won't stop the corrosive process occurring on the metal, but it can provide some protection from moisture which will limit rust development.
What is the best primer for rusty metal?
Rust-Oleum rusty metal primer is considered one of the best on the market.
How long does it take for paint to dry on rusty metal?
Spray paint on rusty metal will usually be dry to the touch in about 10 minutes but can take 1-2 hours to fully dry.
Spray paint can be used on rust and is much more effective than traditional paint. In fact, you can save a lot of money using spray paint to rejuvenate old metal pieces, but just remember that paint won't reverse the rust; it will just cover it up. Hopefully, this guide has given you some useful information, and you now have a better idea of how to approach your rusty metal DIY projects.