A friend of mine needs a vacuum pump for some research he's doing about "free" energy. Each man hunts his white whale...
You can order one on EBAY and wait 2 months, or you can build it yourself, or try at least
I was recently given a fridge compressor. I made is a crude version of a vacuum pump, some kind of mock up to see if it could work.
First test is encouraging, it goes to -27 inHg (= -0.9 BAR or -13 PSI). The manometer may be a little optimistic.
Second test with a bottle: