Ultra high pressure water jetting is a method of surface preparation that uses water projected onto a surface at pressures between 25,000 and 36,000 psi. No abrasives are used in the operation as water jetting relies on the energy of the water striking the surface to achieve the preparation standard.
All coatings and surface contaminants have a removal threshold energy which is predominantly sheer rather than tensile. If the water jetting exceeds this threshold the coating and contaminants will be removed. When using UHP water jetting as a process of surface preparation, part of the energy kinetic used is transformed into heat. The heat raises the temperature of the substrate and accelerates the evaporation of the water and the drying of the surface. The metallic steel surface will quickly ginger as a result of surface oxidation, this is known as flash rusting.
An additional benefit of using UHP water jetting as a method of surface preparation is that any soluble salts and invisible surface contamination will be removed. Surface tolerant primers must be utilised after the UHP water jetting process in order to obtain the optimum adhesion strength between the primer and the steel surface.