Surface preparation is one of the most important factors in the successful application of a coating or surface treatment and is critical to the effective lifetime of the coating. For any coating to perform successfully it is essential that the substrate is prepared properly.
Ensuring the correct surface preparation optimises the performance of the coating and material usage. Elcometer supply a range of products to meet each of the key industry standard surface preparation inspection methods, including surface condition, blasting parameters, surface profile, surface roughness and surface cleanliness.
The proper and effective preparation of a surface prior to coating is essential. Making sure that the correct roughness – or profile – has been generated is essential.
If the profile is too low, the adhesion of the coating to the surface will be reduced. Too high and there is the danger that the profile peaks will remain uncoated – allowing rust spots to occur. If the profile is too high you will have to use more paint to cover the profile and the chance of paint at the bottom of the values not curing will also be a potential problem. Surface contamination from salts such as chlorides, sulphates and nitrates have been shown to lead to blistering of organic coatings, particularly in immersion conditions.
It is not sufficient to measure the cleanliness of the substrate. In a multi-layer coating process, it is necessary to monitor and record the cleanliness of each layer prior to applying the next coating. When using amine cured epoxy coatings, for example, in low ambient temperatures or in high humidity, a surface oiliness or exudate may cause inter-coating adhesion failure.