Waterjet cutting is highly effective for foam, rubber, and gasket materials, and contrary to intuition, these materials typically emerge dry or nearly dry despite direct exposure to a high-pressure water stream. This is achieved through a combination of machine design parameters, material behavior, and cutting strategy.

First, the waterjet stream used for soft materials is usually pure water (abrasive is not required). The pressure is significantly reduced—often to 10,000–30,000 psi rather than the 60,000 psi used for steel. The small orifice (typically 0.003 to 0.010 inches) produces a fine, coherent jet that cuts primarily through localized erosion and shearing, not by soaking the material.

Second, the cutting speed for soft, porous, or elastic materials is extremely high. Foam and rubber are cut at traverse speeds of 200 to 500 inches per minute or more—orders of magnitude faster than metal. The jet passes over any given point in milliseconds, leaving insufficient time for water to be absorbed or wick into the bulk material. Additionally, the water that does contact the surface is immediately flung away by the high-velocity jet and the air turbulence surrounding it.

Third, for non-porous rubber and solid elastomers, water simply cannot penetrate the material. The jet cuts by eroding a narrow kerf, and the surrounding material remains sealed. Any residual surface moisture evaporates within seconds. For open-cell foam, some water may enter exposed cut cells, but this is limited to the cut edge itself. Because the cut is extremely fast and narrow, the volume of water involved is minimal relative to the foam's surface area. If necessary, a blow-off nozzle or vacuum table can be added to the waterjet system to remove stray droplets.

Fourth, gasket materials such as closed-cell foam, neoprene, or compressed non-asbestos fiber are often hydrophobic or have sealed surfaces. They repel water naturally. Many gasket manufacturers specifically choose waterjet cutting because it produces a clean, ravel-free edge without heat (unlike laser) and without mechanical distortion (unlike die cutting).

Finally, for applications where any moisture is critical—such as medical foam or certain adhesives—the waterjet can be fitted with a "dry head" system. This uses a very low water volume and an assist gas (typically compressed air or nitrogen) to clear the kerf. Alternatively, the material can be sandwiched between sacrificial layers of plastic or paper that absorb or block moisture from the cut edges.

In summary, waterjet cutting avoids wetting damage to foam, rubber, and gaskets through high cutting speed, low pressure, the non-porous nature of many elastomers, minimal water exposure per unit area, and optional drying accessories. The result is a clean, dry cut edge without delamination, swelling, or adhesive failure.