Flash rusting is a rapid form of corrosion that occurs on typically an iron or steel surface, but can affect most any metal. From as little as a few minutes to a couple of hours, if a metal surface were to be clean/blasted and then left unprotected in a humid environment, the thin layer of reddish-brown rust can start almost immediately.

So, knowing just how pervasive flash rusting can be, how do you prevent it from happening? Humidity control, moisture removal, and immediate coating application are key strategies.

Humidity Control

One of the most effective methods to prevent flash rusting is by controlling environmental and ambient conditions. By reducing humidity levels in a work area, you can significantly slow the rusting process. Lower humidity minimizes the presence of water vapors in the air, thereby reducing the risk of rust formation. Additionally, managing humidity helps prevent condensation, further protecting against the early stages of rust. Using dehumidifiers or humidity control systems in storage and work areas can make a substantial difference in maintaining the integrity of metal surfaces.

Implementing an effective humidity control strategy involves continuous monitoring and adjustment of the environment. Advanced humidity control systems can automatically adjust the levels to ensure optimal conditions are maintained consistently. Additionally, proper ventilation plays a crucial role in humidity control by allowing air circulation, which helps in reducing moisture buildup. The use of hygrometers and other monitoring devices is essential to keep track of humidity levels in real-time, enabling prompt corrective actions when necessary.

Moisture Removal

Moisture accelerates the oxidation process, leading to rust formation. By removing moisture, you interrupt the corrosion process by eliminating a crucial element necessary for rust to develop. This not only prevents rust but also provides a cleaner surface for coatings, ensuring better adhesion and performance of primers and paints. Techniques such as using compressed air systems, dehumidifiers, and desiccant dryers are effective in removing moisture from both the air and the surfaces being treated. Regular monitoring of moisture levels and maintaining dry conditions are essential steps in effective moisture control.

In addition to these techniques, proper storage practices for metal surfaces can further aid in moisture removal. Storing metals in dry, climate-controlled environments prevents exposure to humid air. Protective coverings and sealants can also be used during storage and transportation to shield the metal from moisture. Furthermore, the use of absorbent materials in storage areas can help in capturing any residual moisture, ensuring the metal surfaces remain dry and protected.

Immediate Coating Application

Applying a high-quality paint, primer, and corrosion inhibitor immediately can prevent the bare metal from being exposed to moisture and oxygen. Including a rust inhibitor in any cleaning solution adds a protective barrier to the bare surface, helping to delay the onset of corrosion. Immediate coating application ensures that the freshly cleaned metal is not left vulnerable to environmental elements. This step is crucial in industrial processes where timing and precision can significantly affect the quality and longevity of the finished product.

The choice of coating materials is also critical. High-performance coatings that are designed to withstand harsh environmental conditions provide long-term protection against rust. These coatings often contain additives that enhance their corrosion resistance. Additionally, the method of application—whether it be spraying, brushing, or dipping—can impact the effectiveness of the protective layer. Ensuring an even and thorough application is key to maximizing the protective benefits.

Using Desiccant Dryers

Now, to maintain optimal conditions for metal surfaces, one effective method is using a properly sized desiccant dryer, which removes all moisture from a system before it is prepped for blasting, ensuring no moisture comes into contact with bare metal. This not only prevents rust formation but also enhances coating adherence and reduces rework time typically needed for reapplying coatings or re-blasting. This process ensures a higher quality end product.

Desiccant dryers work by absorbing moisture from the air, providing a consistent supply of dry air for blasting processes. This is especially important in environments with fluctuating humidity levels. By maintaining a dry environment, desiccant dryers help in achieving a uniform and clean surface, ready for coating application. They are an essential tool in industries where precision and quality are paramount.

Product Highlight: Blast Pak PRO

In terms of products, one commonly used for preventing flash rusting is the Blast Pak PRO portable compressed air-drying system by Van Air Systems. This all-in-one system keeps compressed air dry, making it ideal for prepping surface areas or performing paint jobs. You might see this unit next to bridges on highways during blasting or repainting projects. Its effectiveness and portability have made it a popular choice for various applications.

It's also widely used in marine blasting at shipyards and for repainting water towers. The portability of the Blast Pak PRO makes it suitable for various applications, and since it requires no electricity, it's perfect for remote areas. This flexibility allows for its use in diverse settings, ensuring that high-quality surface preparation and coating application can be achieved even in challenging environments.


Preventing flash rust requires a combination of humidity control, moisture removal, and immediate protective measures. By implementing these strategies and utilizing advanced systems like the Blast Pak PRO, you can maintain the integrity and longevity of metal surfaces, ensuring superior results in all your industrial projects. Proper planning, continuous monitoring, and the use of high-quality equipment are essential to effectively combat flash rusting and achieve the desired outcomes in your operations.

Desmond Merzius is new to the Van Air Systems family. He joined our team about a year ago and is the regional manager of our western territory. Desmond has multiple years of experience in equipment sales for the agriculture industry along with the rental and construction market. Desmond has quickly learned about all the aspects of our products, along with their applications and technical specs. Outside of work, Desmond enjoys spending time with his family, hunting, and fishing.

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