What constitutes a good paint job? One that is able to withstand diverse environmental conditions? One that is able to protect your substrate (painted surfaces)? Or is it a paint job that has a nice presentable finish? We believe that a good paint job should be able to cover ALL three. But how can we avoid the premature failure and paint defects dreaded by all owners and achieve a good paint job at all times?

Today, we are going to take a look at some commonly found Paint Defects. It is usually easily preventable and If you are currently facing it – don’t worry, there are easy solutions to help you fix the defects

What causes Paint Defects?

There isn’t one specific reason that causes the failure of a coating as many potential factors may be involved. In fact, most of the paint defects are attributed to more than one contributing factor. These factors include:

1. Formulation of the paint
   Be sure to find the right formulation of paint suited to your substrate. If you are using the incorrect formulation, paint failure would be high as it is not suited to the environment and/or surface of your substrate.





2. Surface preparation
   Surface preparation is the most important step that is often overlooked. A poor surface preparation may cause many issues as the coating would fail to adhere to the surface properly. You can read more about surface preparation here.





3. Application
   The proper application method with the right tools is vital to avoid coating defect. Be sure to take into account your substrate surface as well as its environmental exposure when deciding on the right application method. Learn more about the right application methods here.



4. Drying & curing times
   Shortened drying and curing time also leads to paint defects. Should you paint over a surface or coat that is not fully dry – coating may experience flaking or cracking. Make sure dampness or moisture is fully removed before applying any coat.



5. Conditions & Environmental exposure
   Different conditions and environmental exposure will test the coating integrity. Rain, sunlight, wind, heat, cold, humidity, and oxygen in various combinations and cycles will eventually lead to premature coating failure. Be sure to use the right formulation and application method to maximise your paint lifetime.

Common Paint Defects

1. Blistering

   

   
   Probable Causes: Formation of bubbles like shapes on the painted surface is known as blistering. The primary cause of this defect is water vapor. When water vapor trapped under the paint layer, it creates bubbles under the film of paint.
   
   Prevention: Ensure correct surface preparation and application. Apply a suitable coating system after testing for water vapor. Consider the possibility of the different causes in the particular environment.


2. Blooming (Blush)

   

   
   Probable Causes: Formation of dull patches on the painted surface is known as blooming. The primary cause of this defect is poor quality of paint and improper ventilation causing it to be exposed to condensation or moisture during curing, especially at low temperature.
   
   Prevention: Apply and cure coating systems under correct environmental conditions and follow the manufacturer’s recommendations.


3. Fading

   

   
   Probable Causes: When there is a gradual loss of colour from the pained surface, it is known as fading. The main cause of this defect is the reaction of sunlight on pigments of paint. This may be due to incorrect pigmentation, use of non-light-stable organic pigments as well as porous substrate.
   
   Prevention: Use correct coating systems that resist ultraviolet light and fading. Use a coating with light- stable pigments.


4. Flaking

   

   
   Probable Causes: In this type of defect, some portion of the paint does not properly adhere to the surface; resulting flaking off of the paint layer. It can be due to incorrect paint system used – usually due to no or incorrect pre-treatment used for certain substrates. It may also be due to poor application techniques or the differential expansion and contraction of paint and substrate, for example, wood. Another possible reason may be due to the aging of the paint system.
   
   Prevention:Use correct coating system and pre-treatment.


5. Grinning

   

   
   Probable Causes: If the thickness of the final coat of paint becomes very thin, the background can be seen clearly. This is known as grinning. Poor application technique is the main cause of this defect or due to strong colour of primer/undercoats.
   
   Prevention: Apply adequate dry-film thickness between individual coats. Use opaque coatings with good opacity.


6. Running

   

   
   Probable Causes: This type of defect is seen when the surface to be painted is very smooth. In case of smooth surface, the paint runs back and leaves small areas of surface uncovered. Overapplication of paint, excessive use of thinners, incorrect (or lack of) curing agent, or poor application technique may be the main causes.
   
   Prevention: Use correct application techniques and apply at the recommended dry-film thickness.


7. Sagging

   

   
   Probable Causes: This type of defect is more prominent when a thick layer of paint is applied on a vertical or inclined surface. Overapplication of paint, excessive use of thinners, incorrect (or lack of) curing agent, or poor application techniques are the probable causes of this defect.
   
   Prevention: Use correct application techniques with suitably formulated products.


8. Wrinkling

   

   
   Probable Causes: This type of defect is more prominent when a thick layer of paint is applied on a horizontal surface. Usually due to the initial formation of a surface skin with solvent-based paints. Can arise from overcoating before the previous coat has adequately hardened.
   
   Prevention: Use correct coating specification and materials, and ensure adequate mixing, application, and curing by following the paint supplier’s recommendations.

When will Paint Defects manifest?

Failures and defects can manifest themselves at various times in the life of a coating. To determine the cause of paint defect, all possible contributory factors must be evaluated together with a detailed history from the time of application to the time the failure was first noted.

Many coating failures require further evaluation and analysis to be carried out by a qualified chemist or coating specialist, often using specialized laboratory equipment. Should you require this service, you can contact us at Royalton & Berger to help you identify your issue to best solve your problem.