Coating Preparation with Wet Blasting Gives Better Surface Finishes
Surface preparation is very essential and an important factor for a successful protection system against metal corrosion. It has to be the first stage that you undertake before you coat any metal surface and requires far more care than the actual application of any paint or other finish.
Any coating will work properly only if it adheres properly to the surface that is being coated. Even residual mill scale on metal surfaces makes for an unsatisfactory base, which can affect the high performance coatings that are widely applied to give the metal products the desired degree of protection. This cleaning process is very effective if the coating preparation with wet blasting is resorted to. It is also very essential that all surfaces are rid of any oil, grease or diet, before any blast cleaning process is attempted. The final surface, prior to the application of coating, must be one, which has a suitable profile to receive the desired coating.
Blasting any surface that requires surface preparation is very effective if abrasive media is used with compressed air to remove all the contaminants and other irregularities on a surface that needs to be coated. In wet blasting, liquid is also introduced along with the abrasive media, and this enhances the level of the surface finish. The liquid used is generally water, and it gives finishes that are more consistent and smoother. It was first introduced as a means of avoiding silica, which did cause health problems to abrasive blast workers. It was found that the use of water allowed flows across blasted surfaces to be more even leading to almost no damage to the substrate and ensuring a consistency over the entire surface being so blasted. This allowed workers to have greater control over the finishing surface required.
Before any wet blasting treatment it is very important that dust, loose particles and other contaminants be removed, by brushing or other methods. If this is not done the high pressure of the wet blast can use these particles to damage the surface. Wet blasting with just water at over 2000 atmospheres is also used to clean walls and remove paints and is a good technique to use for surfaces which are porous. This method of coating preparation with wet blasting ensures that old material in the pores also gets removed. Wet blasting is also less damaging to surfaces which can result when abrasive material or wire brushing is used. This type of water jetting is also use to prepare asphalt surfaces to remove tire build up, which can prevent newer surfacing materials from adhering to the surface.
It is important that surface temperatures during wet blasting be at least a couple of degrees above dew point, so that there is no condensation, which can affect the final surface. The finishes are finer in coating preparation with wet blasting because of the flushing action of the water. This ensures that the blasting media does not remain on the surface and damage it further.