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    September 21, 2023

    The Impact of Weather on Metal: Understanding Corrosion Protection

    Any time you’re talking about metal, be it a commercial fishing vessel or a HVAC cooling tower, strength and durability reign supreme. Because metal is only as strong as you need it to be when it’s in pristine condition, a silent adversary lurks. Corrosion threatens to erode the very foundations of metal’s structural integrity. 

    As time goes on, metals that have not been regularly maintained with a cold galvanizing product succumb to oxidation, the scientific term for rust. Of course, it is not actually time that causes rust, but the outdoor elements metal is in for days, weeks, or years. It is important to understand the challenges metal faces when it is outside, as well as the pivotal role of corrosion protection the cold galvanization plays. 

    Let’s dig deeper into two key ideas — the profound significance of the weather's impacts on metal assets, as well as what ZRC does as a corrosion preventive compound to prevent it.

    The Effects of Rain on Metal

    Even more so than “regular” water, rainwater harbors a hidden threat to metals. This is because it is slightly acidic due to the dissolution of carbon dioxide in the atmosphere. When rainwater contacts metal surfaces, it initiates a chemical reaction known as oxidation, setting the stage for serious corrosion. The oxidation process is further exacerbated by the presence of impurities and contaminants within the rain, everything from airborne pollutants to natural salts and minerals. These impurities act as catalysts that speed up the corrosion process and lead to the formation of rust.

    Metal made to be outdoors, from an iron gate to a broadcast tower, faces prolonged exposure to rain. Over time, the corrosive effects accumulate. This constant assault from above gradually weakens the metal. Over time, you will notice surface pitting, etching, cracks, and fissures. Beyond just an unsightly appearance, this corrosion compromises its structural integrity.

    In outdoor environments, such as bridges, railings, and pipelines, where exposure to the elements is inevitable, rain-induced corrosion can significantly reduce the expected lifespan of these structures. This isn’t just costly, but dangerous as well. It necessitates repairs, as the compromised structural integrity resulting from rain-induced corrosion poses a potential safety hazard. Leaving corrosion unchecked is a safety hazard and replacing metal assets is expensive, underscoring the importance of regular corrosion protection measures. 

    ZRC Cold Galvanizing Compound is ideal to use in rainy places, like South Florida, Texas, and the Pacific Northwest. The zinc dust in our cold galvanizing compound is used to provide 

    corrosion protection because the zinc makes it electrically conductive. Zinc sacrificially corrodes instead of the metal itself, thereby protecting the metal asset left out in the rain.

    It’s important to note that we recommend checking the weather forecast before applying ZRC in rainy climates. You’ll want to give yourself about 48 hours of dry time after applying the paint before it rains again so you can enjoy the full protection our cold galvanizing compound provides.

    Metal in Snow and Freezing Temperatures 

    All the above is not to say rain is the only outdoor element that puts metal at risk, far from it. Freezing temperatures, accompanied by snow and ice, introduce a unique set of challenges to metal structures. When water freezes, it expands, exerting tremendous pressure on the surrounding materials. For metals, this can be particularly detrimental. If there are existing microscopic cracks, pores, or imperfections on the metal surface, water can infiltrate these spaces. As it freezes and expands, it exacerbates these fissures, widening them. When the ice eventually melts, it leaves behind a larger, more accessible entry point for moisture and corrosive agents, setting the stage for accelerated corrosion. 

    This is a vicious cycle for metal’s structural integrity. If a tower is left to rust and corrode, it grows weaker and weaker. Then, snow and ice come again and the added load from the new weight will make it break altogether. 

    When snow blankets a metal surface, it can effectively trap moisture beneath it, preventing natural evaporation. Trapped moisture often goes through cycles of freezing and thawing, like from day to night, further stressing the metal and promoting corrosion.

    Freezing temperatures, snow, and ice form a formidable problem for metal structures in northern climates. These factors pose a significant threat to the longevity and integrity of broadcast towers, many of which are in places like Wisconsin and North Dakota. To mitigate these risks, corrosion protection strategies, such as regular inspections and coatings of ZRC to fortify metals against the harsh winter elements, are essential.

    Corrosion Protection in Extreme Heat

    Extreme heat also poses a serious threat to metal structures, as it accelerates corrosion. As temperatures soar, metal surfaces are subjected to a phenomenon known as “thermal expansion.” It causes the metal to expand, potentially widening existing cracks. If moisture is present, like from recent rainfall, it can penetrate these vulnerable points, exacerbating the corrosion process. Extreme heat cracks the metal and gives moisture even more routes to get inside and cause serious damage.

    In environments with extreme heat, it is imperative to choose corrosion protection methods and materials that are specifically engineered to withstand these conditions. Additionally, regular inspections and maintenance become crucial to identify early signs of coating degradation or metal corrosion, allowing for timely intervention and preservation of the metal's integrity. By understanding the intricate interplay between extreme heat, thermal expansion, and protective coatings, you can implement effective strategies to fortify metal structures against the relentless forces of corrosion.

    In environments with extreme heat, it is imperative to choose corrosion protection methods and materials that are specifically engineered to withstand these conditions. Applying ZRC in extreme heat, areas like South Florida, California, Texas, and Arizona, is not an option — it’s a necessity. Regular inspections and maintenance is crucial to identify early signs of coating degradation or metal corrosion, allowing for preservation of the metal's integrity and timely intervention before a catastrophic collapse. 

    User Guide: Galvanic Corrosion Prevention

    The Effects of Strong Wind on Metal

    When you think of weather that has a negative effect on metal, wind is often overlooked. The truth is that wind-driven particles, propelled by the force of gusting winds, play a significant role in the abrasion-induced corrosion of metal surfaces, especially on bridges. As these particles whip through the air, they collide with the metal's surface, creating micro-abrasions. They are tiny but, over time, they can wear away protective coatings and expose the underlying metal to the elements. 

    In regions where bridges are subjected to strong, persistent winds and rainwater, such as coastal areas, this abrasive action becomes particularly pronounced. The metal on bridges is doubly threatened! The continuous barrage of wind-driven particles not only accelerates the degradation process, but also weakens the protective measures in place, leaving the structure increasingly susceptible to corrosion.

    ZRC Cold Galvanizing Compound passes ten-year subtropical exposure testing and exceeds ASTM A780 standards for hot-dip galvanic repair. Four 4" x 8" panels of 1/16" thick hot rolled steel were white blasted (SSPC SP 5) and spray coated with one coat of ZRC Cold Galvanizing Compound at various film thicknesses. They were exposed in South Florida by Q-Lab Weathering Research Service. Panels were each backed and edged with an adhesive white vinyl tape of 5 mils in thickness. Both front (ZRC coated) and back (bare with vinyl tape) were evaluated after 10 years continuous exposure, and the results proved ZRC helps metal stand up to extreme heat and sunshine. 

    How Humidity Plays a Role in Corrosion

    We’re not done talking about coastal areas like Florida quite yet! Humidity is a critical factor in the corrosion process, especially in places prone to moisture exposure like commercial marinas. When humidity levels are high, the air is saturated with water vapor, providing an ample source of moisture for metals. This moisture facilitates the electrochemical reactions that drive corrosion, as it enables the movement of ions between the metal surface and the corrosive agents. 

    In marine environments, where humidity levels are naturally elevated due to the proximity to water bodies, the impact on metal corrosion is particularly pronounced. High humidity, combined with the presence of salt in the form of sea spray or mist, accelerates the corrosion process. The salt acts as an electrolyte, enhancing the flow of electrical currents between the metal and the corrosive agents, thereby expediting the formation of rust.  This leaves commercial fishing vessels, floating docks, and other structures vulnerable.

    ZRC cold galvanizing compounds offer portable, flexible protection that can be applied for this use case. It is available as an aerosol product, meaning you can spray it on round and oddly-shaped parts, as are commonly found on boats. The ability to get it into the curves and the cracks means it can be applied directly onto the boat. Metal pieces don’t need to be removed in order to add protection against humidity!

    Learn More About the Financial Reasons to Keep Up With Weather-Related Corrosion

    When left outside to face the elements, no matter what the weather is, metal will always corrode. Trying to skimp and save by ignoring your metal asset’s needed maintenance leads to paying more in the long run. The only way to truly save time, money, and stress is to do the job correctly, before it actually must be done. The cost of a ZRC cold galvanizing compound is minuscule compared to major repairs and replacing the metal altogether.

    In fact, we have the numbers to prove it. In The Total Cost of Corrosion: Comparing Using ZRC vs. Replacing the Metal Structure, you’ll see actual facts and figures that back up how expensive it is to let your metal assets rust away and how affordable it is to use a corrosion preventive compound instead. Download your free copy right away to learn more.