I am looking for a high pressure pump (3000-4500) psi. I finally got the idea that I could use a pump like this: Hand Pump I think they have a built in reservoir but I think I could pump into it at around 100 psi from a pre-compressor. Will this work or can it not pump air. Also, would it need oiled because it doesn't have the oil flowing through. Just so you know I wouldn't be pressuring a vessel to 4500 psi by hand, I would rig up a motor for this.