Evaluation of Wet Blasting for Ship Application

Abstract

This paper presents the results of a field investigation of equipment and technology for wet abrasive blasting as a technique for preparation of structural steel for painting. Ten different commercially available wet blasting units were selected for field evaluation. The units selected included the following generic types: air abrasive wet blasting (addition of water at the nozzle to conventional dry blasting equipment); air/water/abrasive slurry blasting (mixing of water with the abrasive at a control unit upstream of the nozzle); pressurized water abrasive blasting (abrasive added to high-or low-pressure water jetting stream); and ultrahigh-pressure water jetting [20000 psi (137.9 MPa) or greater]. These evaluations were conducted on steel surfaces, typically encountered in shipyards and industrial environments, including rusted and pitted steel, milscale steel, and painted steel. The investigation considered factors such as the cleaning rates, abrasive and water consumption, operator thrust, portability, safety procedures required, use of inhibitors, and overall practicability and reliability. The paper discusses each of these factors and provides a tabulation of advantages and disadvantages for each unit observed.