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Moondog
09-23-2004, 09:46 PM
Starting to think about Vacuum Systems for my build. 8 * 4 table.

Vacuum pump systems appear to be very expensive and this has led me to find out more about Venturi Vacuum systems.

Is a Venturi system suitable or sufficient for a succesful vacuum system on a 8*4 table. Panels products and holding of parts.

your input and advice appreciated.

cheers

ger21
09-23-2004, 10:01 PM
I think you'll have a hard time getting it to grab large panels. On large commercial machines, they use very high volume pumps with lower vacuum. A venturi can pull more vacuum, but with very little volume. Also, a venturi pump will be very intolerant of leaks, unless you have a very large reservoir. The problem is, if the panel is not perfectly flat and sealed completely, the venturi pump won't be able to grab the part and form a seal.

Having said that, I plan on trying to use a Venturi system on a smaller scale, maybe
3 x 4ft. Now that I think about it, you maybe be able to break the large table into smaller more manageable zones, turning them on one at a time as you get each section stuck. Make sense?

Take a look at http://www.joewoodworker.com
I built an automatic venturi system for veneering for probably around $75.

Moondog
09-23-2004, 10:34 PM
Thanks Ger...

My thought was to divide the surface area into.. say 4 sections so you could use only 1 section etc.... but will the Venturi be sufficient to use all of the sections.

DDM
09-23-2004, 11:13 PM
Ger21 thanks for the link www.joewoodworker.com, has a bunch of useful stuff on there even if he is a little opinionated which is good so you can see his view point of stuff. Maybe a link to ad to the links page if it isn't already there.

Carl

witold
09-24-2004, 03:28 AM
Very inefficient! You will need a lot of compressed air to produce even small volume of the vacuum!

Moondog
09-24-2004, 09:06 AM
so it looks like I'll need to look at a conventional vac sys?..... any ideas on what capacity I would need and type?

ger21
09-24-2004, 09:17 AM
Very inefficient! You will need a lot of compressed air to produce even small volume of the vacuum!

Not if you can get a leak free seal. With an automatic system (with check valve and vacuum switch), My veneer press will only run about 10-15 seconds every 1/2 hour. At about 25-28" of Hg.

But, you must have a very good seal.

Woodsmith, issue #40 I think, has an article on making clamping jigs with a venturi pump.