jump to example.com

Rather than buying a vacuum pump for clamping and veneering, connect Black Jack’s vacuum generator up to your air compressor as your vacuum source. You just need to make sure your compressor can supply 3CFM @ 90psi. Black Jack doesn’t state the pressure drop the generator can achieve, but all the retailers use 10psi drop in pressure for their example calculations.

Instead of using a pump, the vacuum generator uses the Venturi effect. Several sites show the handy diagram above to demonstrate the vacuum generator works. Compressed air is blown through a funnel which pulls the air surrounding the funnel along for the ride. Since this surrounding air is supplied by the attached vacuum line, it lowers the pressure in that line.

It looks like you’ll pay around $80 before shipping for the Black Jack Vacuum Generator.

Black Jack Catalog [Black Jack]
Vacuum Generator [Workshop Supply]
Vacuum Generator [TheToolStore.ca]

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10 Responses to Make Your Air Compressor Suck

  1. Adam says:

    Given that a venturi pump has no moving parts, it meets my criteria for things that can be purchased from Harbor Freight. $15:


  2. Aaron says:

    Why not buy one of these?


    It’s the same thing, just a whole heck of a lot cheaper ($15). I have one of these which I use for it’s intended purpose and it will pull 28-29″ of vacuum which is nearly 15 psi.

    • Eggman says:

      28-29″ of mercury (vacuum) is a negative pressure. Where psi is positive pressure. They are two completely different items.

      • Jonathan says:

        True, but they are not totally different. Often vacuum pumps are used for vacuum bagging, pressing, clamping, chucking, etc. When you pull a vacuum in a given space the atmosphere applies positive pressure on that space. So
        29.92 “Hg (inches of Mercury) = 1 atmosphere of pressure = 14.7 psi (or nearly 15psi as the other commenter stated.

  3. Cameron Watt says:

    Handy but not as efficient as a vacuum pump….but the less you use it the less it matters.

  4. fred says:

    Same concept used in cellar drainers:


    The also selll ones for permanent installation in places where combined basement flooding and power outages can be ameliorated using the municipal water supply to help drain a basement sump.

  5. Byron says:

    The HF one is just as good, and often $7 on sale. One problem all these have is the fact as soon as the air is off they vent the vacume (there’s no moving parts…thus no valve to close).

    Add a one-way check valve (the 1/2″ brass ones work well) to the business end makes it much more usable. A cheap, simple upgrade.

    But don’t believe that 3CFM @ 90psi rating; You’re going to need to hold at least three times that solid to make one of these work well if at all. The design is intrinsically an air hog.

  6. shotdog says:

    I’m with Adam. If something from HF has no moving parts, ok. Just be sure to use a lot of teflon tape on any air chucks you buy there. I bought a drill press vise which I first used to drill out a cylinder from end grain. It was so far out of square I thought I’d mounted the piece incorrectly. Turns out the vise bed was GROSSLY out of level. The crap HF sells comes from China with nary a thought nor a nod to quality control. sd

  7. kramman says:

    I use something like that at work to change the oil in small engines. It can drain about 1qt of oil in a min or two. It’s made by “Vacula” if im not mistaken.

  8. Jermaine jensen says:

    So I’m using a old sand blaster unit to spray recycled glass aggregate onto an epoxy resin. When done we have to sweep up the excess aggregate that doesn’t soak into the resin. So I was wondering would a venturi valve concept work on my operation to turn my compressor into a giant vacuum or does the theory only work with liquid and gas since the solid material would clog up the air way?

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