Preparing Ferrous Metals for Painting

Painting is the process of coating a material with a protective layer in order to reduce oxidation and extend the material’s usable life and or applying a coating for decorative purposes.


When you are painting IBR sheeting, palisade fencing or anything else in and around your home, it is of utmost importance to follow the correct steps and techniques to ensure the quality and longevity of your coating.

Ferrous metals either contain, or are derived from iron. Examples of ferrous metals would be fabricated sheet steel and wrought iron – all prone to rust. Rusting can start very rapidly when unprotected ferrous metals are exposed to elements of nature. It is of utmost importance to stop and remove any rusting that has begun to guarantee that there is no compromise to the appearance and longevity of the paint job and the material itself.

Surface preparation is considered one of the most important factors when it comes to the coating quality of your end product and vital to the success of any paint job. Removing any visible rust and peeling paint would be the very first step when preparing any ferrous metal surface for painting either by wiping the surface with a cloth or brushing with a soft bristle brush. In some cases, with a more abrasive material would be necessary whereafter the surface can be scrubbed with a water-based degreaser and then rinsed off with clean water. Depending on the size of the job on hand and the severity of the imperfections on your surface this can be achieved by the use of various abrasive products. Hand or power tools might be used dependent on what you have in your toolbox.

Great results can be achieved by hand sanding with wet or dry abrasive sheets, starting with a coarser grit size for aggressive stock removal of imperfections working towards finer grit increments until the desired surface finish is achieved. When it comes to working with a power tool, wire brushes, abrasive sanding discs and non-woven rough cleaning products are all ideal for this application.

Always remember to wear the correct personal protective equipment which should include eye protection and a good quality dust mask. New ferrous metal surfaces where imperfections might not be visible to the naked eye should also be prepared adequately to avoid a premature failure of your paint job. New metal often has mill scale or oil on it or small amounts of rust not yet visible. The timing of your preparation and applying your primer and topcoat is of utmost importance. If the prepared surface is exposed for as little as a day or two the surface will have to be prepared again. Always be sure to apply a quality rust-inhibitive primer before applying your final coat.

Galvanized metal is iron or steel with a thin coating of zinc to prevent rusting. Galvanized metal is commonly used for gutters, downpipes and flashing. If the galvanized surface is new or weathered it should be washed and rinsed thoroughly before painting. This process cleans off any zinc chromate or residual oil that could have been left on the surface from the galvanizing process which otherwise can interfere with the adhesion of the paint.

On previously painted galvanized surfaces all rust and peeling paint should be removed with a wire brush, abrasive disc or non-woven abrasive product. Always try and avoid cutting through the layer of zinc galvanizing during this process. Always be sure to apply a quality rust-inhibitive primer before applying your final coat.

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