Pete, if you don't want noise and do not require lots of air evacuation, try a water venturi vacumn pump, you probably remember them in the school lab, cheap simple, use a surprising little amount of water and can pull a surprising amount of vacumn. The thing they cannot do is evacuate huge amounts of air quickly like a mechanical pump. We used to use them for calibrating aircraft instruments and 50000ft was pretty achievable in a round glass goldfish bowl with a 10mm ali plate lid. A 10K dollar rig for about $ 100.00