How to Paint Rusted Metal

How to Paint & Prepare Rusted Metal to Last

Some rust and corrosion are more pronounced, ranging from contact areas to structural supports such as metal handrails, steel exterior doors, exterior metal hardware, and steel brick lintels.

When we see rust, it’s unsightly, and instinctively, we want it removed. But the truth is that the damages are already underway once the rust is visible. While processes and preparations will help with the rust removal process, ultimately, rusted metal requires protection from future exposure, resulting in rust. We will explain how to paint rusted metal surfaces and prepare the surface.

What Causes Rust?

Steel is a commonly used metal. It is used for building materials, exterior home furniture, and more. While steel is solid, it has limitations. The main drawback is rust. 

The composition of steel includes iron and carbon. A combination of air and water causes the iron particles in steel to rise and flack off at an accelerated rate. 

Most exterior steel materials used on homes, such as doors, have a layer of primer that resists rust. Red Oxide primers have been used for years but only slow the rusting process. No primers will exceed, keeping exterior metal substrates dry. However, industrial oil-based paints protect longer and reduce future maintenance. 

An industrial paint will last longer and replicate a factory-like finish. Powder-coating metal also offers enhanced metal protection. 

Industrial Coatings & Non-Industrial Coatings

Applying a durable exterior metal-specific paint will make painting metal more manageable, and you will be happier with the results. While a few store-bought metal paints provide moderate performance for homeowners, they are not considered high-performing coatings.

Manufacturers such as Rustoleum have a brand-recognizable reputation, providing fast and straightforward solutions for homeowners. While Rustoleum does offer industrial products, Rustoleum paints found in home improvement stores are not recognized as industrial finishes. 

Industrial coatings must meet specific OEM standards, while non-industrial paints are not required and have minor criteria other than hazardous material labeling standards. 

The Best Coatings For Rusted Metal

We will say there is a balance between usability and durability when deciding which coating to use for metal. When the balance between the two starts to lean heavily toward being hard to use due to viscosity, dry time, or special tools required, we recommend hiring a professional painter. 

Metal coatings range from acrylic, alkyds, epoxies, and urethanes. Industrial urethanes provide ultimate durability without compromising usability as epoxy would. 

If you are a professional house painter or an experienced homeowner, here is a list of a few industrial coatings, primers, and solution treatments worth considering. The following coatings provide durability and well-balanced application measures.  

Rust Inhibiting General Use Metal Surface Primers & Solutions

Industrial Metal Surface Top-Coats

Tips For Painting Rusty Metal

Painting over rust will not last. For best results, you must remove the rust. However, an entire removal can be time-consuming and expensive. So, in most instances, combining sanding and scraping is most common. 

You can also use a rust-inhibiting solution with light scraping to improve surface conditions significantly. While a clean surface is essential to resisting further rusting, the surface must be dry no matter how extreme or light the rust removal process you choose. Choose a day when the relative humidity is low, if possible.  

Note: The purpose of this article isn’t to provide comprehensive safety details. However, always protect yourself by wearing a mask and gloves. Rusted iron particles are something that you do not want to inhale.

The Best Process to Paint Rusted Metal

  1. Blast exterior metal surfaces using a pressure washer to remove mold and mildew. Use a non-bleach mold-killing solution, as bleach contains sodium. 
  2. Remove loose rust particles with a wire wheel for machine use or a wire brush for manual use. 
  3. Sandblasting can also be utilized for commercial or large applications.
  4. You can opt to apply a rust-inhibiting solution to prepare the surface further. 
  5. Wipe down the surface, removing all debris and discoloration.
  6. Sand the entire metal structure using 120-grit sandpaper.
  7. Prime the entire metal surface. (Make sure to use the appropriate primer to adhere to the existing substrate.)
  8. Top-coat with an industrial-grade coating. (For ultimate results, apply the first coat with a brush and spray the second coat when two coats are necessary.)

Note: Cover the surface after the coating is dry when painting dark colors. Covering will mitigate potential water spots caused by evening storms or high early morning due points.

Tools that Will Expedite the Process

Comparing Coatings For Metal

Epoxy vs. Powder Coating: Whether painting an industrial coating or applying a solution, rust-inhibiting properties are essential to painting metal exposed to rust. However, not every metal surface will benefit from powder coating or a 2 part epoxy. While they may be the most effective applications, they are not cost-effective or always viable. 

Powder coating is typically done within a shop. Therefore, the metal structure would have to be removed. Two-part epoxy’s thicker viscosities and super-fast dry times make them more challenging to apply. In short, epoxies are fantastic, but brushing a dark-colored epoxy on a hot day is not happening.

Urethane Enamel: A urethane enamel provides the most durable coating that can be easily managed and applied to several surfaces by multiple means of application.

Conclusion

There are multiple products when considering durability, cost, rust elimination, and color retention. We offered the options and procedures to bridge the gap, making the process accessible and lasting with an industrial-style coating. 

The opinions of local store sales clerks or painters can be pervasive. We hope this article has helped and applies to your situation. If you need service in the Raleigh area, feel free to contact us anytime!

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