Turn that old metal into a shiny new penny
Maybe your vintage metal patio set needs a facelift, or maybe the rusting sconces you scored at a flea market could use a little TLC. Applying a quick coat of paint is a quick and easy way to update or extend the lifespan of metal surfaces around your home. However, painting metal surfaces requires a specific technique, so follow this guide on how to paint metal surfaces the right way.
If you’re changing up a metal surface for your home, you may think you can dip a paintbrush in, slap on a fresh coat of paint, and call it a day, but you’ll need to prepare if you want a long-lasting metal paint job. Here are some things to know about preparing your metal surface.
When painting metal, primer is a must. Picking a primer isn’t always straightforward, however. You have to factor in the state of your metal surface. Some surfaces are in good shape and only require a single coat of metal primer or spray primer. If your metal has been subject to a lot of weathering or wear and tear and is far from its heyday, it might require two coats.
Always choose a rust-inhibiting primer like zinc chromate or iron oxide to protect your metal from rusting. A spray primer is best for very uneven metal surfaces, while a traditional metal primer that you apply with a brush or roller is ideal for smooth surfaces.
There are two main types of metal paint you can choose from for this unique project: water-based and oil-based paint.
Water-based paint is ideal for painting indoor spaces because it offsets fewer volatile organic compounds (VOCs) and is more likely to chip compared to oil-based paints.
Oil-based paint is the best paint for metal surfaces outdoors because it’s more durable and longer-lasting. If you use oil-based paint, plan your project to include a longer drying time of around two days, and be sure to wear a safety mask while handling this type of metal paint.
Knowing which tool to use for the job helps ensure your paint lasts. Brushes and rollers will give you a very distinct look and require a different application technique when compared to spray paint. While there are pros and cons to both, your choice will ultimately depend on what you plan to paint.
Spray paint: Best to avoid brush strokes on irregularly shaped objects with lots of nooks and crannies, this method is your fastest-drying option for painting metal. But, because spray paint produces a thinner coat, the paint won’t last as long.
Brush or roller: Though this method takes longer, using a brush or roller gets you a thicker coat on outdoor items that need greater protection from wind, sun, and rain. Painting with a brush or roller offers more controlled application outside, which can be useful if it’s breezy.
Safety should be at the forefront of any project you work on, and painting metal is no exception. According to the Centers for Disease Control and Prevention, working with rusty metal poses potential health risks, including:
Lacerations that can lead to tetanus
“Metal fume fever” from exposure to iron oxide fumes
Eye abrasions
It’s important to work in an airy environment while removing rust from old metal, if possible. You should also wear gloves, eye protection, and a face mask to avoid injuries or illness.
The primer you need for the project will depend on the type of metal you’re painting. Essentially, there are two basic types of metal: ferrous and nonferous metals. Ferrous metals are iron-based metals that are receptive to rust. These metals include:
Wrought iron
Steel
Cast iron
Nonferrous metals include:
Aluminum
Copper
Stainless steel
Zinc
Pro tip: Sometimes, ferrous metals are covered in a thin layer of zinc to help avert rust. If you’re working with a metal like this, it can be treated as a nonferrous metal when applying primer.
Rust and old paint can prevent fresh paint from sticking properly to a metal surface, which leads to premature flaking or peeling paint. To prevent this from happening, you’ll need to remove any obstructions before you paint. Depending on the extent of the rust, you may need one or more of these rust removal tools:
A wire brush for everyday surface rust
A wire brush drill attachment for larger areas of caked-on rust
A liquid rust remover for soaking and removing the most stubborn rust spots
Vigorously scrub the metal surface, removing as much rust and old paint as you can.
Once you’ve removed the rust and peeling paint, clean the surface with mineral spirits, which is a petroleum distillate commonly used as a paint thinner. You can buy mineral spirits at almost any hardware or home improvement store locally.
Cleaning metal with mineral spirits instead of water will better prepare the new paint to stick to the surface of the metal. Don’t use water to clean your metal, as doing so will only lead to the production of more rust over time.
Just like a textured, blank canvas, metal paint projects work best with tiny etchings on the surface to hold the primer and paint in place. Sand the entire metal surface with fine-grit sandpaper, giving it a thorough go-around.
With your surface prepared, it’s time to apply a primer to the metal. For pieces that have stubborn rust, you’ll need to apply a coat of zinc chromate first to prevent further rust. Use a spray primer for metal surfaces that have many crevices, and use a brush or roller if you’re applying conventional primer. Apply two coats to be on the safe side, and allow the primer to dry according to the manufacturer’s instructions.
Once the primer is completely dry, apply an even coat of paint to your freshly primed metal with a brush, roller, or paint sprayer. Let the coat fully dry, and then apply one more coat if you’re using a brush or roller. If you’re using a paint sprayer, repeat the process until you have three thin coats.
While some paints dry relatively fast, you’ll still want to wait for a good one to two days for the paint to cure before you move the metal. If the paint isn’t cured before you try to move it or apply a sealer, you could run into peeling, streaking, and other less-than-aesthetic side effects.
To prevent chipping, rusting, or fading, spread a clear-coated sealer over the final layer of paint. Be sure to choose a sealant meant for painted metal, as some sealers are made only for bare metal. You can apply the sealer with a sprayer, roller, or paintbrush.
Most metal paint projects are easy projects for avid DIYers, but there are times when you should consider hiring a local painter to do the job, as just knowing how to paint metal isn’t always enough. Metal surfaces with excessive rust can pose a safety risk and might be unsalvageable, while some metal projects require extensive labor, such as painting a metal roof.
If you’re on the fence about whether you can paint a rusty piece of metal, your best bet is to ask the pros. Know that the cost to hire a professional painter is significantly higher than the cost to DIY your project. You can get away with spending between $100 and $200 to DIY a metal paint job, but the price to hire a professional painter ranges anywhere from $200 to $6,000, depending on the project.
Paige Bennett contributed to this piece.
Oil-based paints stick best to metal surfaces because the solvent in the paint contains the mineral turpentine, which adheres better than water-based paints. Flaking, blistering, and peeling are all less likely when you use oil-based paints, but these blemishes are very common if you use a water-based paint on metal. While oil-based paints are longer-lasting, their sheen tends to wear off over time.
Brushes, rollers, and spray paint are the best ways to paint metal surfaces, depending on your project goals. Spray paint is the easiest method for painting metal and can make painting complicated pieces with many curves and grooves a breeze. However, using traditional paint with a roller or brush creates a harder, more durable finish.
Yes, primer is an essential step for preventing rust formation on your newly-painted metal surface. Additionally, primer can help the paint stick to the metal better and can slow down the formation of rust if you buy a rust-inhibiting primer. Just be sure to avoid water-based primers, which aren't made for metal surfaces.
Yes, you can paint over already painted metal, but—before painting—you’ll want to use sandpaper on the area to achieve a rough surface. This helps prevent the paint from peeling or flaking. Remove damaged paint with 120-grit sandpaper. If the paint is in good condition, use 240-grit sandpaper. Brush off any dust before applying the primer.
Using a wire brush, forcefully scrub the surface to remove paint from metal. You’ll want to remove any lingering rust, too. For larger areas with caked-on rust, you may need to use a wire brush drill attachment. If the paint still won’t budge, apply a chemical paint stripper to the area and scrape off the paint, after following the paint stripper’s instructions.
