Abstract: A blast cleaning machine for pipes includes means for supporting the pipe in a horizontal position and for rotating the pipe about its axis. The machine also includes an enclosure mounted above the pipe supporting means and the enclosure has a lower opening which is positioned in use close to the upper side of the pipe. A centrifugal blast wheel receives abrasive from a hopper and blasts the abrasive in a downwardly inclined direction through the opening and on to the pipe surface. The spent abrasive rebounds from the pipe surface into a conduit by which the abrasive is conveyed to a reclaim zone in which the abrasive is separated from dirt and other foreign matter and is then returned to the hopper for re-use. The machine can be adjusted for cleaning of pipes of different diameters and in the region of the said lower opening there are interchangeable components by which the size of the opening can be varied according to the pipe diameter.