Date: Thu, 3 Oct 2002 15:29:35 -0400 (EDT)

Author: Richard Berg

Subject: Re: Vacuum Cannon question

Post:

We used relatively thick walled tubing that we machined smooth and
flat. Then it was sealed by a small plastic plate on both ends to pump
the vacuum; a tad (physics term) of vacuum grease helps with small
cracks. Take a look at our setup:

http://www.physics.umd.edu/lecdem/services/demos/demosi3/i3-18.htm


Dick Berg

On Thu, 3 Oct 2002, Stephen Irons wrote:

> Hi All,
>
> I've just put together a vacuum cannon and I need advice on what the
> best way to seal the ends is. I've used ordinary clear 3M packing tape
> with some success, but the ordinary stuff isn't quite wide enough so I
> have to put two pieces across each end to cover it(kind of a drag and it
> is prone to leaks). Furthermore, if the cannon isn't fired
> expeditiously, the tape eventually fails catastrophically and
> unpredictably. I then tried ordinary heavy duty Reynolds (as suggested
> by the NCSU website), but that failed almost as soon as I started to
> pull the vacuum. Is there a heavier duty foil I should use? (I checked
> MMC, but they appear to have only 0.001" thick which is the same as
> Reynolds Heavy Duty).
>
> Thanks for your help.
>
> -Stephen.
>
> **********************************
> Stephen Irons Yale
> University
> Director, Instructional Laboratories Department of Physics
> tel: 203-432-3664 P.O. Box
> 208120
> fax: 203-432-6175 New Haven,
> CT 06520-8120
> email: stephen.irons@yale.edu
>
>

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Dr. Richard E. Berg, Director Phone: (301) 405-5994
Lecture-Demonstration Facility FAX: (301) 314-9525
Department of Physics e-mail reberg@physics.umd.edu
University of Maryland www.physics.umd.edu/lecdem
College Park, MD 20742-4111
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