Iron has long been a favorite for railings, fences, planters, benches, and gates. Cast or wrought, the metal is strong, nontoxic, doesn’t burn or rot, and is impervious to insects. There’s only one problem: When exposed to moisture, iron rusts. Given enough time, every bit of the hard metal will dissolve into red dust.
Still, there are steps you can take to preserve your metalwork outdoors. Below, blacksmith Bob Bernard shows how to get an old wrought-iron gate looking new again, a project that took just four hours over two days.
Challenges of Outdoor Metalwork
Moisture, salt air, and temperature fluctuations all make metal surfaces deteriorate. To keep your metalwork beautiful and rust-free, regularly inspect it for issues and address any damage quickly to prevent bigger problems.
Rust is the primary threat to outdoor metalwork. When iron or steel is exposed to moisture and oxygen, it undergoes a chemical reaction that forms iron oxide, or rust. Corrosion is a broader term that includes rust and other forms of metal degradation. It can be particularly aggressive in coastal areas or regions with high pollution levels.
Tools and Materials for Metal Protection
Below, we’ve listed the various tools, materials, and products you’ll need for different methods of outdoor metal protection. Follow all directions closely to ensure you’re using the right tools for your project.
Cleaning Supplies
Cleaning the metal surface thoroughly is the first step in protection. For this, you’ll need the following:
- Steel wire brush
- Sandpaper (80-grit)
- Mineral spirits
- Protective gear (gloves, goggles, mask)
Rust Removal Products
Proper rust removal prevents further degradation. You’ll need a phosphoric acid-based rust converter, such as Ospho, and a metal file or scraper.
Primers and Paints
Using high-quality primers and paints that resist weathering. Gather the following:
- Oil-based metal primer
- Oil-based metal paint (preferably glossy)
- Disposable bristle brushes (chip brushes)
Reviving Metalwork in 5 Steps
1. Scrub
First, rub a steel-bristled wire brush over all metal surfaces to get rid of loose paint, flaking metal, and powdery rust.
2. File
On flat surfaces, use a mill bastard (coarse) file or a scraper to grind rough patches of rust down to bare metal. On rounded surfaces, 80-grit sandpaper does the trick. Wipe down the surface with mineral spirits to remove residue.
3. Neutralize
Spray all exposed metal with phosphoric acid, which converts any rust you’ve missed or can’t reach into a black, inert crust of iron phosphate. Apply the product according to the manufacturer’s instructions, making sure you completely cover all exposed metal. Be sure to protect your eyes, skin, and lungs from the spray.
4. Prime
Wait a day for the acid to penetrate and react fully with any rust, then brush away any loose flakes. Apply a thick base coat of oil-based metal primer using a disposable bristle brush, also known as a chip brush. Pay special attention to corners, crevices, and intricate designs.
5. Paint
Let the primer dry before putting on the finish coat with a new chip brush. Choose an oil-based metal paint, preferably one made by the same company. Black is the traditional color for ironwork. A glossy sheen lasts longer than a flat finish.
Painting Ironwork
To give wrought iron a smooth painted coating, it helps to move methodically from top to bottom. Using a series of quick brush strokes up from the top rail, paint each bar all the way around. Where a bar is topped with a finial, paint the finial first, then halfway down the bar, then up from the rail.
Brush out from each bar’s base until the paint film is continuous. Paint the rail’s underside around each bar in the same fashion. Paint each bar completely before moving to the next.
Brush with downward strokes all around and most of the way down each bar. Then paint up from the bottom rail. Follow the same sequence as the upper rail, and brush each one down from the bottom rail.
On wrought ironwork with intricate scrolls, coat the crevices where a brush can’t reach with spray paint. Apply light coats to avoid drips, and immediately brush out any overspray. Finish all the spray painting before brush-painting the rest of the work.
Intricate designs with many crevices and joints are more susceptible to corrosion. These areas can trap moisture and dirt, accelerating the rusting process. Apply extra protective coatings in these areas and make sure they’re cleaned thoroughly.
Maintain Outdoor Metal Art
Here are some best practices for cleaning and maintaining your ornamental metalwork.
Regular Cleaning
Clean your metalwork regularly to prevent buildup of dirt and moisture that can accelerate corrosion. Use a mild soap solution and a soft brush, rinsing thoroughly with clean water and drying completely. Smooth surfaces are generally easier to clean, while textured surfaces have more hidden crevices and may need more attentive scrubbing.
Touch-Ups
Inspect your metalwork annually for any signs of damage or wear. Touch up any chips or scratches immediately with primer and paint to prevent rust from taking hold. Keep small amounts of matching paint on hand for quick repairs.
Seasonal Care
Adapt your care routine to the seasons to make sure that your metal is protected and prepared for any situation. Consider applying an additional protective wax coating before the cold season begins, especially in regions with harsh winters. Remove the wax in spring and reapply your standard protective finish if needed.
Environmental Considerations
Moisture, salt, temperature, and other climate conditions impact your metal’s life and appearance, so take these into account when caring for it.
The air in coastal areas is often saturated with salt, increasing the risk of corrosion. Use marine-grade paints and coatings specifically designed to withstand salty environments, and make sure to remove salt deposits.
High pollution levels can accelerate the corrosion process in urban and industrial settings. Use an anti-pollution coating to provide an extra layer of protection. If you live in one of these areas, be sure to clean the pollution buildup from your metal surfaces.
Professional Techniques for Preserving Metal
Professional preservation techniques may be required for valuable, antique, or more intricate pieces.
Patina Application
A controlled patina can add character to some metal sculptures while providing a protective layer. Professional conservators can apply chemical patinas that improve the artwork’s appearance and protect it against the elements. This method requires expert knowledge for the best results, so we recommend contacting a professional.
Waxing Methods
Apply a high-quality wax for an additional barrier against moisture. This method is particularly effective for bronze but can be used on various metals.
Advanced Coating Systems
For valuable or historically significant metalwork, consider professional-grade coating systems. They include specialized primers, corrosion-inhibiting paints, and clear protective topcoats designed for long-term outdoor exposure. Have a professional apply these treatments for safe, quality results that last.
Protecting Bare Metal
For bare metal, make sure you choose the right type of protection for your needs.
Paint vs. Clear Coat
While paint provides protection and lets you customize your metalwork, clear coats can showcase the metal’s natural charm. When deciding, consider your overall home decor and your local climate.
Galvanization
For steel, hot-dip galvanization provides a durable zinc coating that improves corrosion resistance. This process is particularly effective for iron fences and structural elements.
Powder Coating
Powder coating is a durable and attractive finish for many types of metal fences and ornamental pieces. This involves electrostatically charging dry powder and curing it under heat, resulting in a tough, long-lasting finish.
