vacuum pump from harbor freight - RC Groups
Thread Tools
Jan 10, 2003, 07:45 PM
Registered User

vacuum pump from harbor freight


Any see these little red vacuum pumps for 15 bucks? Say they can pull somwhere around 25 or so inches. Says "venturi" style?
thanks
shane
Sign up now
to remove ads between posts
Jan 12, 2003, 02:54 AM
Registered User
A venturi sytle of vacuum pump is not very usable for vacuum bagging. To get a Vacuum air from an air compresser is passed through a tube with a small hole in the side. The lower pressure in the tube caused by the fast moving air from the compresser will generate a vacuum, but not too much. The cost is the large volume of air required from the compresser. They are not very efficient. I'll look at the one you describe as soon as I can. Some time next week I can get by a Harbor Freight store. Happy flying!
Jan 12, 2003, 06:37 AM
I'm All Thumbs
AirBornOne's Avatar

"Venturi effect" for vacuum source...


Quote:
The lower pressure in the tube caused by the fast moving air from the compresser will generate a vacuum, but not too much.
It depends on the venturi design and the available cfm and psi available.
This technology is used to inflate the escape slides on passenger jets.
Even 2-3" Hg. is acceptable for 1#/sq.ft foam wing skinning.
A vacuum source without any mechanical positive displacement stuff has
got to some merit by virtue of it's longevity.
The way I would use this device would be to plumb the vacuum line to a
'tank' and run a line from the tank to your bag & wing setup with a valve.
Life sucks...make the best of it.
Jay.
Jan 14, 2003, 07:42 AM
Registered User
here is a guy using one for bagging

http://www.rocstock.org/wizards/fiber101.vac1.html
Jan 18, 2003, 12:41 AM
Registered User
Well there you go! everybody should have a 3hp compresser with a 40 gallon tank.. I used an old compresser from a refrigerator and hooked up to the intake side. Enough vacuum for me. OOps don't get caught letting all of that Freon out though while acquiring the compresser! I got mine about 20 years ago! Happy Flying!