Application Failure Series – Uneven Gloss (Flashing) in Paint

Industrial Paint Problem – Uneven Gloss

Whether you consider an industrial equipment or component of any industrial product, you will find that it has multiple layers of coating on it. From a base primer layer to top coating, every industrial component undergoes a series of steps in painting before it gets suited for use. Each layer of paint has its own specific function and adds to the durability of the product. Top coatings on products provide protective layer against corrosion, abrasion, chemical resistance and also adds to their aesthetic properties. But, if the top coat has not been applied properly, it can deteriorate the appearance of the product rather than adding to it.

One of the most commonly faced problems with top coating is uneven gloss or flashing. If a painted surface has dull or glossy patches on the paint film, it is identified as flashing and it generally appears on freshly painted surfaces. There are several reasons why a top coat is affected by uneven gloss, most common reasons include –

  • Paint was applied on porous surfaces without application of primer. When primer is not applied, top coating of glossy paint tends to emphasize the defaults of surface, giving an uneven look.
  • Even if the primer was applied to the surface, the layer is too thin or primer applied is inadequate.
  • Thickness of paint coat was uneven or paint was not mixed properly before applying.
  • Surface painted was uneven or the paint was not spread evenly.
  • Thickness of coat applied was too thin or only a single coat of paint was applied.
  • Oil-based or alkyd gloss was used on areas that are directly exposed to sunlight. Flashing also occurs when solvent-based epoxy coating is used in areas experiencing direct sunlight.
  •  Uneven gloss may occur if the substrate was affected by humidity or rain while drying.
  • Tools used for application of top coat were changed in middle of the paint process.
  • Surface experienced temperature variations while dying.
  • Coating was applied when the surface was too hot or too cold.
  • Improper mixing of paints or applying paints of different blends on surface, then bubbles of paint may develop on the surface.

Ensuring that paint surface has uniform porosity is important to avoid problem of uneven gloss on painted surface. Understand and pay attention to painting procedures and you will be able to maintain the sheen and finish of painted surface for many years.

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