LSD25 - 28-1-2008 at 02:27
I decided today, as I was at something of a loose end (still a lot of projects to finish, but all need some part or component or chemical which is
either unavailable, in transit, beyond my means or whatever), to make a decent manual syringe-type vacuum pump from simple materials.
Although these pumps are of limited usefulness of themselves, when they are used to evacuate a small-medium vacuum resevoir, they allow for small to
medium vacuum distillation. Of course by themselves, they are extremely useful for vacuum filtration.
Anyhow, see what you think (comments welcome)
PS At the top of the stroke (max compression - atmospheric pressure) the height of the headspace is around 1cm. The stroke is around 20-25cm so the
expansion is around 20 times the headspace. This thereotically means that the pump is capable of pulling a vacuum of around 1/20 atm.
http://tinyurl.com/28fe39
microcosmicus - 28-1-2008 at 10:07
Nice little hack --- a piston vacuum pump built without a machine shop. Your price
of $50 and a day sounds like a conservative overestimate to me, or do the toilet
uncloggers retail for an exorbitant price? Likewise, the work involved sounds
more like a half-hour to me.
As for rocket surgery, I suppose you could instead fill the syringe with propellant
and launch it 
chemrox - 28-1-2008 at 15:44
Nice pix. I've never seen anything like this in the hardware stores where I live. It's labled vacuum/suction. Did you write that on it? For under
$50 you can buy a hand-operated vacuum pump; often sold as a "brake bleeding kit." I use one to keep my vacuum dessicator evacuated.
Who is affraid of aspirators? I modified my plumbing to accomodate one and it pulls 25 torr. The backflow trap is essential- when anyone runs water
nearby the flow changes and water runs into the trap. Other than that, its a really nice steady 25 mm for filter flasks or distillations that can run
with that high a pressure. I don't see how you could use your device for anything but filtration or as I do for the dessicator.