Metallic spray paints can be notoriously difficult to use for inexperienced auto repair enthusiasts. Incorrect application can result in metal flotation, poor color matching and unsightly halos that cause shadows in the finish once clear coat has been applied. If these problems occur, the vehicle will usually have to be painted again and this leads to unnecessary material wastage and expense. Effective metallic paint application requires the right techniques, a superior quality product and the use of the correct spraying equipment.
HVLP Spray Guns
All modern metallic paints should be applied with a high-volume low-pressure spray gun. HVLP spray guns are specifically designed to apply greater volumes of metallic paint using lower compressed air pressures for easier application and minimum material wastage. They can be up to 60 percent more efficient than a conventional gravity or suction-fed spray gun and consist of fluid tip set-ups and air caps that atomize paint more consistently for even application.
Material
Avoid the use of inferior paint materials from high street auto stores. Instead, purchase paint products from a reputable trade dealer and stick with brands that are widely used throughout the automotive repair industry. Modern materials are designed to flow easily, cure quickly and they can resist adverse weather conditions once they have been applied.
Cleanliness
Metallic paint application can be compromised by poor preparation, especially where cleanliness is concerned. Only apply metallic paint in a clean working area with sufficient dust extraction and always wipe down the panels to be painted with a compatible de-greasing agent before wiping off any loose traces of grit or fibers with a tack cloth. This will leave an ideal surface that is ready to accept paint.
Paint Application
Always apply a full, wet first coat with metallic paints, irrespective of whether they are water-based or solvent based. This will allow for sufficient material coverage to prevent transparency problems at a later stage and will also provide a gripped adhesive coat for subsequent layers. Always allow the first coat to cure sufficiently until it is matte in appearance. The second coat should be applied at approximately 80 percent of the volume of the first coat and left to cure for a similar time period. Always paint from a distance of 6 inches and maintain constant arm movement to reduce the risk of runs and sags.
Drop Coat
The drop coat is the most critical part of metallic paint application. Reduce air pressure by approximately 50 percent and reduce paint volume by the same amount. Apply the final coat from a distance of 9 to 12 inches so it drops onto the panel in atomized form. Remember to cross horizontal coats with a subsequent vertical coat to ensure uniform coverage. The drop coat should be left to cure for 10 minutes before clear coat is applied.
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