Ultra High Pressure (UHP) Hydro Blasting uses a pump which forces water from a nozzle, usually a rotating head at pressures exceeding 1700 bar (can be up to 3000 bar today).
From the point of view of applying a coating to an old, already profiled, steel surface this method is thought to be the best surface preparation for ballast tank refurbishment. The steel becomes very clean after UHP blasting. It will not remove mill scale and therefore cannot be used as a method for new steel. This must be remembered when making steel repairs.

Advantages

• Extremely clean surfaces can be achieved
• HB 2 and even HB2.5 can be achieved
• No grit to be cleaned up or discarded
• Good for localized Corrosion iwo weld seams etc as well as larger areas.
• Preferred method for riding squad / in service refurbishment

Disadvantages

• Requires a lot of fresh water.
• Very expensive equipment and spares.
• Slower blasting rate than conventional grit blasting (it can be argued that clean up time is less).
• Must be carried out by professionals.
• Difficult to feather surrounding coating, so extra grinding is necessary.
• Cannot effectively remove mill scale on new steel.