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The importance of surface preparation before coating
06.05.2019

The importance of surface preparation before coating

Surface preparation is essential for properly coating with best results. The way in which the treatment is done influences the resistance of the coverage. 

It is really important to keep under control:

  • the cleaning degree of the surface to be processed
  • the contamination level 
  • the profile

After blasting a surface it is mandatory to verify its cleaning degree as most coating systems needs a standard level for achieving the best results.  

Elcometer 128 Swedish Rust Standard ISO 8501-1:2007 is a pictorial standard with high quality plasticized photos in which the cleaning degrees for rusted steel processed through blasting, manually or by flame are presented on 4 different levels. 

The surface contaminations before coating can lead to premature deterioration of the cover, which will exfoliate and won’t resist in time. These contaminants appear due to several reasons: the working area is placed near the sea, the abrasive used for cleaning purposes can also be contaminated with salt, the water used for washing the area is also be contaminated. 

Once the presence of salt on the surface is detected, this can be removed in order to ensure a long-term resistance of the painting layer applied afterwards. 

Another aspect to be considered is the dust contamination. Applying the coating on an area full of dust generates a low adhesive capacity of the coverage.  

For detecting the above-mentioned situations, Minex offers a wide range of measure and control equipment. 

  • Elcometer 138 Bresle Salt Kit – for detecting the salt existing on a specific surface
  • Elcometer 138 Abrasive Soluble Salt Test Kit – for detecting the soluble salts in the abrasive material
  • Elcometer 134 W Chloride Ion Test Kit for Water – for detecting the salt in the water used for cleaning or blasting purposes

The surface profile influences the overall performance of the coating and determines the adhesive capacity, the cover degree and the overall quantity of paint that is needed for best results. If the surface profile is too big, more paint will be necessary. 

The surface profile can be estimated with the help of the following equipment:

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