Which surface preparation technique involves using a high-pressure water stream?

The correct choice is high-pressure waterjetting. This surface preparation technique utilizes a powerful stream of water at extremely high pressures to clean and prepare surfaces. High-pressure waterjetting effectively removes contaminants, old coatings, and debris from surfaces such as metal, concrete, and other materials without the use of chemicals or abrasive substances.

The technique is notable for its versatility; it can be adjusted in pressure and flow rate to suit different materials and levels of contamination, making it ideal for various industrial cleaning applications. High-pressure waterjetting also minimizes the risk of damaging the substrate compared to some abrasive methods.

In contrast, stoning involves using a stone tool to manually grind down surfaces, scarifying is a mechanical method involving the use of equipment to scratch or roughen surfaces, and hand cleaning employs manual tools or cloths to remove surface contaminants. Each of these methods serves different purposes in surface preparation, but only high-pressure waterjetting utilizes the specific high-pressure water stream characteristic of this technique.