What Part Does Water Quality Play in Pretreatment?
Water may be the most important component in the pretreatment process. 95% or more of the pretreatment process chemistry is water. It is important to give some thought to water’s contribution in your pretreatment operation.
The primary role of water is to remove chemical/soil residue and contaminants from the work area, providing a contaminant free surface for optimum coating adhesion and performance. Therefore, water quality is critical to achieve your customers specified coating performance standards.
Directly related to your water quality are the impurities or contaminants that your water contains. One major problem area in the pretreatment process is high TDS (total dissolved solids) accumulating in the rinse water, and being deposited on metal parts during rinsing. When the water evaporates, these impurities are left behind. PH balance also needs to be maintained. Generally, the closer the PH is to neutral (7) and the lower the TDS, is when you achieve the best water quality.
Poor water quality results in:
- adhesion failure
- warranty claims
- excessive water treatment costs
- environmental compliance issues
Good water quality is an extremely important key to your pretreatment process, and should be monitored and controlled routinely, efficiently and effectively.