Date: Thu, 03 Oct 2002 13:40:10 -0500

Author: "Stephen R. Skinner"

Subject: RE: Vacuum Cannon question


Brad first build the cannon I now use many years ago. He used 1.5" PVC
pipe. The ends are each fitted with a 1.5" pipe coupler. A square piece of
aluminum foil, 4"x4" is placed over the ends and then the pipe coupler is
firmly pushed over each end. This works great as long as you are careful
not to crease or tear the foil.

Stephen R. Skinner
University of Arkansas
Physics Department
Laboratory Curator
Office 501.575.6059
Fax 501.575.4580

-----Original Message-----
[]On Behalf Of Stephen Irons
Sent: Thursday, October 03, 2002 1:13 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 Irons Yale
Director, Instructional Laboratories Department of Physics
tel: 203-432-3664 P.O. Box
fax: 203-432-6175 New Haven,
CT 06520-8120