The sand must be screened. Compressed air pressure at 0.4 to 0.6 MPa. Note personal safety protection when sandblasting. Note gun and blade retaining considerable distance, to prevent the blade labeled pits. In addition, the gap between the impeller and shaft sleeve must be packaged using cloth. Use a cloth to package the cervix of axis, thrust plate, and critical security machine and other shaft head components. Prevent the sand stuff into the gap causing unbalance mass of the rotor and other issues.