Abstract: A method for removing hard coatings from an underlying surface is shown and described. In a preferred embodiment, a nozzle having a particular geometry is used in a high-pressure fluid system to produce an ultrahigh-pressure fluid fan jet. The fan jet is traversed across a surface to be cleaned, thereby removing a layer of material without damaging the underlying surface. The effectiveness of the coating removal is improved by selecting an appropriate power distribution for the fan jet, a standoff distance between the fan jet and the surface to be cleaned, the speed with which the fan jet traverses the surface and the length and diameter of a settling chamber existing upstream of the nozzle.

Abstract: A method for uniformly roughening a surface through use of an ultrahigh-pressure fluid fan jet has been shown and described. In a preferred embodiment, an ultrahigh-pressure fan jet is generated by pressurizing a volume of fluid, and forcing the pressurized fluid through a fan jet nozzle. The fan jet is positioned relative to the surface to be treated at a desired distance, and the fan jet is traversed across the surface at a selected rate to uniformly roughen the surface. In a preferred embodiment, the achieved surface roughness is quantified and compared to a desired surface finish. Operating parameters, such as horsepower and traverse rate, may then be adjusted accordingly to achieve the desired surface finish. By uniformly and completely roughening a surface through use of an ultrahigh-pressure fan jet prior to applying a coating to the roughened surface, adherence between the surface and the coating will be improved.