Date: Thu, 03 Oct 2002 14:30:27 -0400

Author: John Cockman

Subject: Re: Vacuum Cannon question



3" tape should be plenty large if you're using 1-1/2" pipe (good for
ping-pong balls). Ziggy told me about this same problem when he first
started doing this demo -- it turned out that his vacuum was too powerful.
Do you have a weaker pump? Also, look for the thin brown boxing tape. When
I first made mine, I tried 3M clear tape. It worked, but it was a little
too thick.


----- Original Message -----
From: "Stephen Irons"
Sent: Thursday, October 03, 2002 2:13 PM
Subject: Vacuum Cannon question

> 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: