• DIY

    How to Prevent Metals from Corroding Part 2

    In part two of our series, we’re looking at how to prevent corrosion with home solutions.

    Preventing common types of metal corrosion with home solutions

    Paint the metal surface

    One of the most common, affordable methods of protecting metal from corrosion is simply to cover it up with a layer of paint. The process of corrosion involves moisture and an oxidising agent interacting with the surface of the metal. If the metal has a protective barrier (in this case, paint), neither moisture nor oxidising agents can penetrate it, stopping any corrosion occurring.

    Of course, paint itself is vulnerable to degradation, so you’ll need to reapply it whenever it becomes chipped, worn or damaged. If the paint degrades to the point that the underlying metal is exposed, you’ll want to inspect for corrosion or damage to the exposed metal before repainting.

    How do I paint a metal surface successfully?

    There are a variety of methods for applying paint to metal surfaces successfully. Metalworkers often use several of these methods on a single surface to ensure that the entire metal object receives a thorough coating.

    1. Paint brush for hard to reach spaces
    2. Paint roller for covering large areas quickly
    3. Air spray for covering large areas, although paint waste is high
    4. Airless spray/electrostatic airless spray for covering large areas, allows for better consistency control but is expensive

    Use marine paint for metal exposed to water

    Metal objects that regularly (or constantly) come into contact with the water, like boats, require special paints to protect against the increased possibility of corrosion. In these situations, “normal” corrosion in the form of rusting isn’t the only concern (though it is a major one), as marine life (barnacles, etc.) are attracted to unprotected metal and can become an additional source of wear and corrosion.

    To protect metal objects like boats and so on, be sure to use high-grade marine epoxy paint. Not only do these types of paint protect the underlying metal from moisture, but also discourage the growth of marine life on its surface.

    Apply protective lubricants to moving metal parts

    For flat, static metal surfaces, paint does a great job of keeping out moisture and preventing corrosion without affecting the metal’s usefulness. However, paint usually isn’t suitable for moving metal parts. For instance, if you paint over a door hinge, when the paint dries, it will hold the hinge in place, hindering its motion. If you force the door open, the paint will crack, leaving holes for moisture to reach the metal. A better choice for metal parts like hinges, joints, bearings and the like is a suitable water-insoluble lubricant. A thorough coat of this type of lubricant will naturally repel moisture while simultaneously ensuring the smooth, easy motion of your metal part.

    Because lubricants don’t dry in place like paints, they degrade over time and require occasional re-application. Reapply lubricants to metal parts periodically to ensure they remain effective as protective sealants.

    Clean your metal surface thoroughly before painting or lubricating

    Whether you’re using normal paint, marine paint or a protective lubricant/sealant, you’ll want to ensure your metal is clean and dry before starting the application process. Take care to ensure the metal is entirely free of dirt, grease, residual welding debris or existing corrosion, as these things can undermine your efforts by contributing to future corrosion.

    Dirt, grime, and other debris will interfere with paint and lubricants by keeping the paint or lubricant from adhering directly to the metal surface. For instance, if you paint over a sheet of steel with a few stray metal shavings on it, the paint will set on the shavings, leaving blank spaces on the underlying metal. If and when the shavings fall off, the exposed spot will be vulnerable to corrosion.

    If painting or lubricating a metal surface with some existing corrosion, your goal should be to make the surface as smooth and regular as possible to ensure the best possible adherence of the sealant to the metal. Use a wire brush, sandpaper, and/or chemical rust removers to remove as much loose corrosion as possible.

    Keep unprotected metal products away from moisture

    As we mentioned above, most forms of corrosion are exacerbated by moisture. If you can’t manage to give your metal a protective coating of paint or sealant, you should take care to ensure it’s not exposed to moisture. Making an effort to keep unprotected metal tools dry can improve their usefulness and lengthen their effective life. If your metal items are exposed to water or moisture, be sure to clean and dry them immediately following use to prevent corrosion from starting.

    In addition to watching for exposure to moisture during use, be sure to store the metal items indoors in a clean, dry place. For large objects that won’t fit in a cupboard or closet, cover the object with a tarp or cloth. This helps keep out moisture from the air and prevents dust from accumulating on the surface.

    Keep metal surfaces as clean as possible

    After each use of a metal item, whether the metal is painted or not, be sure to clean its functional surfaces, removing any dirt, grime, or dust. Accumulations of dirt and debris on metal surface can contribute to the wear and tear of the metal and/or its protective coating, leading to corrosion over time.