Sciencemadness Discussion Board

Diy $4 lab Vac pump:: multi stage reynolds handi-vac

niertap - 25-9-2012 at 21:11

Questions, then details.

1. I read silicon is somewhat permeable to a vacuum (as I guess all polymers with a reasonable % O), but am unsure if it's noticeable during temporary use or just long term gaskets and whatnot.

2. How well do acrylic caulk/superglue, rubber cement, hot glue gun(what an amazing device). any alternatives work out?

3. Will 1/8''d polypropylene fishtank tubing hold up to any kind of external pressure or will it just squish closed in the middle?

So I was at Biglots admiring their reasonably cheap merchandise ( not within reason.. as in there is likely a good reason something's so cheap) When I stumble upon a shelf of reynolds handi-vac food vacuum bag starter kit things. All $3 a piece. Most don't work and I figure the batteries are dead, but thought they could possibly be made into a reasonable lab vacuum pump and buy 3.

Turns out a cell was wonky and that it leaked some of its electrolyte into the battery apparatus. I cleaned it out a little and put 6 AA's into it to see how well it pumped. It gave okay results (around the suction of a house vac.). Then I tried 4 AA LiFePO4s and it worked astonishingly well. One pump at 14v approached a lab pump in power and would work well for filtration.

I only really question what the duty cycle on it will be.

Considering building something with 2 parallel and then a 3rd for higher vacuum in series behind.

Will update with anything useful.

zed - 26-9-2012 at 12:29

Small diameter plastic tubing...ability to hold up to vacuum? It depends on the wall thickness.

Small diameter tubing with adequate wall thickness, can hold up to a lot of either internal or external pressure.

If you have goodly length of small diameter stainless steel tubing, it can in effect become high pressure reactor. Under some circumstances, such tubing can stand up to many thousands of pounds of pressure.