Feasibility of Using Diesel Injection Pumps for DIY Water Jet Cutter: Seeking Expertise

I am currently considering building my own water jet cutter. There isn't much information available on this topic. There is the video from Applied Science, and there are the "affordable" desktop water jet cutters from Wazer. Both use a high-pressure pump from a pressure washer, which explains the relatively low pressure of 300 bar. On Wazer's website, you can find the technical specifications that help estimate the required pressure and flow rate.

What I am now wondering is whether a diesel injection pump could be used as a pump. These pumps can reach pressures of up to 2500 bar, and a flow rate of 2.5 l/min might be sufficient with a thin nozzle.

However, further research reveals a few problems:

• Diesel pumps are lubricated by the fuel, which means that water would likely cause issues. I have thought about flooding the pump with oil after each use to ensure lubrication (not sure if that would work, just an idea).
• Technical data on these pumps, particularly the flow rate, is hard to find. According to this page, the CP4 pump from Bosch has a flow rate of about 1 l/min, which might be insufficient.

My question is whether anyone has more expertise in this area and might better assess whether this would be feasible in principle.

... a friend of mine was designing and building (commercial) water jet cutters -- his pumps delivered from 4000 to 6000 bars and used clean water or added abrasive dust - then with nozzles out of sapphire or diamond.

With so much lower pressure it should be much easier to get it DIY ... but maybe too, yo can look into sapphire or ruby nozzles, as used for FDM-3D-printing.

For another project I found some "pneumatic resistors", what essentially is a thin tube made of ruby with same outer diameter (IIRC 2mm) and different bores from 50 to 300 microns (my selection then - there are more than that).

Generating the pressure is another task - here we used commercial pumps, so can't give pointers ...

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Viktor
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