Date: Wed Dec 26 11:22:07 2007

Author: Cliff Bettis

Subject: 2B30.70, Vacuum Bazooka design

Post:
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Hi all,

When I first built my vacuum bazooka, it worked well sometimes putting a =
ping pong ball through three cans. However the last time I used it, it =
embarassed me. I discovered the immediate problem was a leak at the =
joint into the pipe at which the vacuum line to the pump is attached. So =
I am considering a better design. The other issue I have had is fouling =
of the pipe with the tape used to seal it. I am using Scotch 375 tape. =
What happens is that bits of the punctured tape get into the tube. They =
are hard to remove and prevent the free acceleration of the ball if left =
in. I am experimenting with a coarse wire mesh at the pipe stubnear the =
end that is punctured to fire the bazooka and different tools to =
puncture the tape, to try and catch the bits that tear away or possibly =
preventing the tearing away in the first place.

I recall some of you mentioned using things other than tape to seal the =
tube. If it doesn't have adhesive on it, that would at least make it =
easier to remove should it foul the tube. Do any of you have advice for =
me?

Cliff
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Hi all,

When I first built my vacuum bazooka, =
it worked=20
well sometimes putting a ping pong ball through three cans. However the =
last=20
time I used it, it embarassed me. I discovered the immediate problem was =
a leak=20
at the joint into the pipe at which the vacuum line to the pump is =
attached. So=20
I am considering a better design. The other issue I have had is =
fouling of=20
the pipe with the tape used to seal it. I am using Scotch 375 tape. What =
happens=20
is that bits of the punctured tape get into the tube. They are hard to =
remove=20
and prevent the free acceleration of the ball if left in. I am =
experimenting=20
with a coarse wire mesh at the pipe stubnear the end that is punctured =
to fire=20
the bazooka and different tools to puncture the tape, to try and =
catch the=20
bits that tear away or possibly preventing the tearing away in the first =

place.

I recall some of you mentioned using =
things other=20
than tape to seal the tube. If it doesn't have adhesive on it, that =
would at=20
least make it easier to remove should it foul the tube. Do any of you =
have=20
advice for me?

Cliff

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