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If you’ve got a shop, you’ve probably got some source of vacuum around, even if it’s only a residential vacuum cleaner for tidying up the floors. And in a pinch, a home or shop vacuum cleaner will do for light duty vacuum applications like running a small vacuum former.

If you’re doing chemistry, however, and may be dealing with organic solvents and their vapors, a vacuum cleaner is not only unsuitable, but unsafe: The plastic parts will degrade in the presence of many organic solvents, and the electrics—which are almost certainly not explosion-proof—may ignite their vapors.

But a proper laboratory vacuum pump is a pricey space hog. Whether you opt for the cleaner, lighter duty diaphragm-type pump or the top-of-the-line heavy duty rotary vane oil pump, you can expect to be out a few hundred dollars, a couple cubic feet of storage space, and several hours a year in maintenance time. If you’re just performing vacuum filtration, stripping solvent, or keeping a dessicator pumped down, it’s not really worth it.

A water aspirator is a common and effective compromise solution. Attached to a faucet, a water aspirator uses the Venturi effect to produce vacuum at the sidearm from the downward flow of water out the bottom. It’s cheap, effective, and reliable, with no moving parts to wear out or maintain. But there are some drawbacks: You need to work near a sink with a faucet and a drain, you have to keep the water running to maintain the vacuum, and all that can make it difficult to maintain dry conditions if your chemistry requires it.

If your shop has an air compressor or other source of compressed gas, however, you can use an air aspirator, also called an “air ejector” and a “Venturi pump,” to create vacuum for light duty lab work. An air aspirator works just like a water aspirator, in principle, but it uses high-pressure air as the working fluid, instead of water. Air aspirators offer all the benefits of water aspirators but with few, if any, of their drawbacks. Analogous devices are used in some vacuum clamps marketed to woodworkers for holding down flat stock during routing or sawing.

I’ve used several of these. The particular model shown here is a Vaccon FastVac VP10-150H that I bought used as part of a mixed lot of ten. Running compressed air from my Makita MAC2400 at 80psi, it works at least as well as any water aspirator I’ve ever used, and better than most. Comparable models are currently selling on eBay for $50-$100, which is only a bit more than a top-of-the-line water aspirator.

If there is a major drawback, it’s that this beastie is loud. Mine came with a detachable silencer, shown removed in the photo above, and it helps quite a bit, reducing the white noise level from “obnoxious” to “bearable.” You’re still not going to be carrying on any intimate conversations with this thing running nearby. The neighbors probably won’t come over to complain, but they probably would if you turned the music up loud enough to enjoy it over the din.

Sean Michael Ragan

I am descended from 5,000 generations of tool-using primates. Also, I went to college and stuff. I write for MAKE, serve as Technical Editor for MAKE magazine, and develop original DIY content for Make: Projects.


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Comments

  1. http://www.harborfreight.com/air-vacuum-pump-with-r134a-and-r12-connectors-96677.html

    The upside is it’s cheap..the downside is it’s “cheap” but it pulls enough of a vacuum to de-gas RTV silicon, resins and plaster.

    This, combined with a stainless steel canister with acrylic lid from Bed, Bath, and Beyond, will make an acceptable or beginning vacuum chamber.

  2. Dave Bell says:

    @skestes – nice HF product for the price. Looks like it’s almost all “silencer”, with the venturi the only visible plumbing.

    On the higher end, HF sells a pretty nice “real” vacuum pump for $175.
    Rated (and reviewed to actually reach) 25 microns, which should be well beyond what any kind of aspiratior can achieve.

    http://www.harborfreight.com/two-stage-3-cfm-air-vacuum-pump-66466.html

    Dave

  3. Dave says:

    Or make one out of some pvc and a couple fittings. I used mine to deflate inner tubes and floaties on a houseboat trip. And if you use the opposite end you can even fill some larger floaties fairly quickly… the air ejector draws more air into larger inner tubes faster than the air compressor alone.

  4. ChrisW says:

    Venturi vacuums were used on the 2″ quad VTRs which I maintained in the ’70s and ’80s. They were used to hold the tape against a semi-circular concave guide which kept the tape pressed gently against the spinning heads. If it failed the tape would be shredded and the heads destroyed. I don’t recall a venturi ever failing, but one time the compressed air supply failed and I was asked to explain to the producer and director why the only copy of their show looked like confetti.

  5. [...] Vaccon Venturi Vacuum Pump [...]

  6. Byron Winchell says:

    Consider also another HF cheapie built mostly of metal. It’s a shop air aspirated vacuum pump also for auto A/C work ($14.99 on sale usually $19.99): http://www.harborfreight.com/air-vacuum-pump-with-r134a-and-r12-connectors-96677.html

  7. this is a really great review! the pictures really tell the whole story. we love vacuum they’re some of the best technology in vacuuming out there. we’re still partial to bagged vacuums too though because the filtration and hepa ratings are hard to beat.

    thanks for this review!

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