Introduction: Simple DIY Vacuum Chamber and Pump

Picture of Simple DIY Vacuum Chamber and Pump

This is an easy to build vacuum chamber that is power with a garden hose.  you can draw 30 cm of vacuum with your hose. simple and easy way to degas fluids like silicone for mold making without buying an expensive vacuum pump.

Step 1: Parts

Picture of Parts

you will need the following parts. many of they can be found or scrounged for free is you have the time.

1 - 6" x 24 " PVC pipe                                Lowe's                                       $16
2 - 1/4 " x 12" x 12" acrylic sheets           (   $12
2 - 1/ 8" x 12 " x 12" neoprene sheets   (           $20
1 - vacuum Aspirator                                 (      $25
1 - vacuum gauge                                     harbor freight                            $13
1 - 3" x 3/8" air hose                                  harbor freight                            $4

                                                                                                                                                                 Total = $90

Step 2: The Vacuume Asparater

Picture of The Vacuume Asparater

this little thing can draw up to and in some cases even more than 30cm of vacuum with only a garden hose. and a only $24 it beats the hell out and expensive pump. it has a ball valve to hold the vacuum when the water pressure changes so when you shut of the hose the vacuum stays.

Step 3: Top and Bottem

Picture of Top and Bottem

The top and bottom are 1/4 " acrillc .
Just trace the tube.
Find the center point, and make a circle and inch farther out.
cut along the outside line.

Step 4: Neopreen Gaskets

Picture of Neopreen Gaskets

use the top and bottom pieces to trace around with a knife to cut out the neoprene.
find the center and then cut out the center circle by hand.

Step 5: Make the Conections

Picture of Make the Conections

drill tow hole just a little bit smaller than the fittings (the vacuum gauge came with a bunch of extra fittings)
heat up the fitings with a soldering iroen and scre them in. when they cool down take them out and wrap with plumbers tape and reinsert them.

Step 6: Finishing the Pvc Edges

Picture of Finishing the Pvc Edges

This is the tough part. if you are lucky the pipe you have will have good edges. This one did not. gab a piece of sandpaper and hold it down with the bottom plate. sand in a circular motion and keep turning the pipe so you don't over sand. Eventually you will get an edge that is good enough for the neoprene.

Step 7: Set It Up and See If It Sucks...


ThomasS59 (author)2017-11-06

This is also called an jet pump. Fire a solid stream out of a garden hose you see the surface of the jet is often not smooth. Air is caught by the water stream and is accelerated to the water speed. The water is expanding as it flows. So it contacts the tube ID but since the surface is ruff of the water jet is traps air in pockets that move with the water to the outlet of the tube. Thus air is removed. The maximum vacuum that can be obtained is the vapor pressure of the water at it's temperature. 30cm or 300 torr or mm of Hg corresponds to about 76C. Thus this is not a very efficient pump at city water pressure of ~60 psi. Connect this to your spray washer with more pressure and if it can deliver the flow the vacuum would be greater. Other choices is a gas ejector compressed air would be the choice of a DIY project but steam in the industrial choice 30 years ago. about 20% peak efficiency. Here is a source "JET PUMPS AND EJECTORS" Green, Andrew J. DOI: 10.1615/AtoZ.j.jet_pumps_and_ejectors.

The next solution is a liquid ring pump which is where industry have gone. They are simple machines that could be made with simple hand tools and plastic sheet stock and fine powder filled glue or silicone rubber. Where the powder size sets the gap between the waggon wheel hub and spoke shaped rotor and the housing with the driving shaft off set, eccentric, from the housing center of a round hole in the sheet of plastic the rotor could have been made from. In and out ports on opposite side plates. The ID is the wheel hub OD, OD is the circle concentric with the housing hole and just touching the hub diameter less the desired seal radius height. The remaining side and the radius on the ID/OD intersection is determined by the angle between spokes. At no time shall the inlet and outlet not have a spoke between them. These pumps get down to the vapor pressure of the liquid. Ice water vapor pressure is 5 torr. One nice thing about liquid ring pumps is that you can put fire, dust, grit, and liquid into them and they continue to turn. a little water is added to keep the temperature low and insure the ring is held at the correct height.

rogersbr (author)2015-08-03

is there a way to make a vacuum system to get to about 10^-5 torr ?? i have ideas but the problem is sealing it

KDS4444 (author)2014-02-14

Um... What about the "pump" part? You showed several brass attachments and you mention a garden hose, but there's no pump here anywhere or am I missing something? Because a vacuum chamber without a pump is just a pretty tube.

WillN1 (author)KDS44442015-01-23

The "pump" part is the flow of water through the nozzle. Air is sucked out of the chamber by the Venturi effect:

Also see Bernoulli's principle:

bassman76jazz (author)KDS44442014-03-27

that is the pump. it uses the a garden hose to pull vacuum.

KDS4444 (author)bassman76jazz2014-03-27

I don't seem to understand where the garden hose attaches or how it draws the vacuum. You have laid out all of the parts of your vacuum chamber, but I don't grasp what "mechanism" is actually "pumping" the air out of it (you say this is a garden hose, and I believe you, but I don't know how to attach one to this to cause it to draw a vacuum).

Hieu (author)KDS44442014-07-01

So you are not understanding the definition of "aspirator" then as Bassman pointed out. The garden hose attach to the end he cut and hose clamped the aspirator to the chamber.

From the physics of things as they are presented here -- the water running draws the air away from the that tube he made air-tight creating a vacuum chamber. A vacuum pump is just something that draws out all the air/fluid from whatever space you need to be left completely devoid of air/fluid. So he did in fact create a vacuum chamber and pump as he stated in his title. If you still don't believe this you can just look at the vacuum gauge and see for yourself if you build one.

A little physics lesson if you still need explanation. As the water rushes out of the garden hose and pass by the tube he created it draws air away from it. As no air can enter the chamber, ultimately the chamber will be left completely empty of air.

So water rushing by the chamber is THE PUMP.

KDS4444 (author)Hieu2014-11-13

I am understanding better, but why does the pump not just start to fill with the water? What keeps the water from filling the vacuum created as it sucks out the air?

There is no pump.There is only a water hose (e.g. a garden hose) with water running through it. Into this hose, another hose has been attached, and this hose goes to the vacuum chamber. The connection of the hoses is shown in the 1st picture in "Step 2: The vacuume asparater". The thin pipe outlet is for the hose that goes to the vacuum chamber, and the water runs through the thicker pipe (direction does not matter).

As water running through the pipe will draw fluid (gas and liquid) from the connected, thinner pipe, a vacuum starts to build into the vacuum chamber. This is known as the Bernoulli principle / the Venturi effect. (Both dudes made huge contributions to the field of fluid dynamics, and I am so waster ATM that I cannot remember which one dealt more with this phenomenon...)

You can see this effect in real life, for example, if you have access to a (small) motor boat that has a (corked) hole on the bottom (to drain out rainwater): Get some water into the boat, go for a ride and when the boat is moving at a decent speed, pull out the cork. The water in the boat will get drawn out, and after it's all gone, air will get sucked through the hole (not that you will notice it).

You either have to run the water as long as you wish to have the vacuum, or install a valve into the vacuum chamber hose and close it when you have reached the maximum vacuum (recommended).

Nevertheless, as I wrote earlier, if you by any means can scrape together the 60USD that a vacuum pump costs, do not even consider this water thing. You would need a 'weapons grade' water pump to get enough vacuum for e.g. stabilizing wood.

BruceC2 (author)Hieu2014-11-07

Nice explanation, but kind of an assholish and snarky tone.

bassman76jazz (author)KDS44442014-03-27

en2oh (author)2014-12-21

nice instructable just one question. How can a vacuum aspirator using water as the working fluid generate a pressure of 30cm of water? If I recall correctly, the limit for that type of pump is the vapor pressure of water at any given temperature I.e. The pressure where water boils at the temperature the pump is operating at. At 25 deg C, that's about 24torr or 24mm Hg. 30cm of water is about 22mmHg wouldn't your water start to boil at 24 mm Hg? You could cool the water some, but this is a practical limit to a vacuum aspirator

nsalling (author)2014-12-20

I really like your Vacuum chamber, it was really cool. I do have a small question: I found a pressure sprayer (one like this: ) and got the idear that i could make it into a vacuum, chamber. Do you think that is possible?

RyanG18 (author)2014-12-01

if you used a 1/2 or 1/3hp submersible pump, you could connect it up to that and get crazy water pressure (much, much higher then you can get from a garden hose) - and you could recycle the liquid back into the same water basin you are drawing from - so it'd be a closed system with the power source being the electricity powering the submersible pump

That is true. I reckon a pressure washer would work also nicely. However, the pressure itself does not matter, only the flow rate of the fluid. Thus, you obviously want to make the water hose as short as possible and/or have a large diameter that reduces only just around where the air tube is connected.

Then again, as you can buy a Chinese low-quality vacuum pump for, what, 50-60USD, nowadays, I wouldn't really even consider anything that uses the Bernoulli principle / Venturi effect. Unless, of course, if you have no electricity available. Otherwise, an electrical pump is the way to go: better vacuum, no worries about the water (easy to use indoors), less electricity consumed as with a water pump, etc.

vincent7520 (author)2013-02-12

nice kids !…


rf (author)2011-07-16

The big production with the 6" tube, acrylic and neoprene was to create a vacuum reservoir?

That 6" tube has end caps and all kinds of other fittings waiting at the hardware store to be used with it. One or two end caps and some glue would seem to simplify things quite a bit. Or perhaps I'm missing something. If you want the ends to be removable there are threaded fittings too.

End caps are nice and thick and can be drilled for smaller fittings too.

Just a thought.

bassman76jazz (author)rf2011-07-17

for one i wanted to see into the chamber and the end caps are rounded not flat so its difficult to degases fluids without a flat bottom. i actuality was looking for a pressure cooker at the thrift shop but i did not find one. also the fittings for 6" pvc are about the same price as the acrylic.

rf (author)bassman76jazz2011-07-18

What you want is a bell jar. They're really not that expensive. You can get a 14-inch diameter bell jar for about the same cost as your materials here. And you can see into it much better.

Not that you didn't learn a lot building yours.

stringstretcher (author)rf2012-06-03

You guys need to be careful when pulling a vacuum on a piece of glass. I managed to avoid the shards when the lid, a piece of 8mm thick glass exploded and flew all over the room. I learned a lesson that day :) Keep the pressures down to safe levels and let time do its part.

rimar2000 (author)2011-07-09

This is very interesting. I need one of these for permeate wood with liquids.

Can you put a layout (schema) of the inner of the vacuum aspirator of step 2?

bassman76jazz (author)rimar20002011-07-09

i bought it at
you can get it with or without the hose adapter.
there is a detailed description there.

rimar2000 (author)bassman76jazz2011-07-10

Thanks, but I live in Argentina. Maybe it is simply a Venturi tube, very easy to do.

askjerry (author)rimar20002011-07-14

I did a bit of searching and found this... it may help you.


stringstretcher (author)askjerry2012-06-03

Wow, I have some old french horn mouthpieces that would make a perfect venturi tube like this! That is what they are, in fact, since they are most often a small bore opening up into a larger bore, increasing the airspeed through the venturi principle.

rimar2000 (author)askjerry2011-07-15

Thanks, but I get "Error. The item you requested could not be found."

askjerry (author)rimar20002011-07-15

I don't know why... I just tried it again and it worked perfectly. Perhaps the server was down when you tried.

I'll try making a link... CLICK HERE

Good Luck,

rimar2000 (author)askjerry2011-07-16

Thanks, now works.

johnny3h (author)rimar20002011-07-14

I'm no expert, but I've had/used one of these hose end vacuum aspirators since high school chemistry some 53 years ago, and it works exceptionally well.

And to answer your question, YES, it does work on the venturi principle.

In studying mine, it is fabricated to very small and tight tolarances which with 30 to 50 psi water pressure allows me to get a vacuum in the 25 to 28 inch range on my cheap vacuum guage.

If you build it well, one of your own making should also work well.

I noticer in the parts section, that bassman bought some of his components from an outfit called Harbor Freight and Tool, which also has a website and sells online.  Check them out and maybe you can get one without having to build it yourself.

Harbor Freight has been a mailorder cataloge sales outfit for YEARS, but now has many stores across the USA, and now has added a website.

Much of their product is made in China, thus the relatively lower prices, but I take good care of all my tools and instruments, and get good service life for the price I pay.  Every once in a while I do get "stung" by a defective product, but it's not often, and they usually "make it right."

And NO, I am NOT an employee of Harbor Freight, and my only connection with them is as a retail customer.

rimar2000 (author)johnny3h2011-07-15

Thanks for the info.

bassman76jazz (author)rimar20002011-07-10

it is similar, and works on the same concept. the one i use has a back flow valve that prevents water from being sucked in when the water pressure is turned off. It also keeps the vacuum in the chamber when the water is shut off. I'm sure you could make on if you wanted to. it just has two small veins that rotate the water form the inlet and a hole behind one of them that draws the air in.

DaveB13 (author)rimar20002011-07-14

I'm off topic for this article. Regarding "permeate wood" is this material I'd stumbled across just yesterday when looking for info regarding a stunning wooden bridge constructed recently ->

Acetylated wood
Titan Wood Inc.
modified wood by Accsys Technologies

Brug = Bridge Akkerwinde = name of a road
Sneek = name of a city in the Neatherlands
Brug Akkerwinde
Akkerwinde Sneek
(for me Google Toolbar can translate Dutch to English)

rimar2000 (author)DaveB132011-07-19

Thanks for this abundant info!

TheREALfatNINJA (author)2011-07-24

Hmm.... I wonder if this could be used to construct a home food freeze drying device.

Pazzerz (author)TheREALfatNINJA2011-10-23

You need a much higher vacuum, preferably with a piston type pump which can be gotten rather inexpensively at places like Harbor Freight. This is one of the projects I am currently working on, which is why I happened to come across this Instructable. The chamber is good, just need a heavier duty pump.

TheREALfatNINJA (author)Pazzerz2011-10-27

Well I was thinking of re-purposing an old vacuum pump used for the repair and maintenance of automotive air conditioning systems. Is that what you're referring to?

Pazzerz (author)TheREALfatNINJA2011-10-29

Yes! I just got a fairly new one and it works very well for that. I'm hoping to find a short section of fairly large PVC drain pipe to better accommodate a standard drying tray, otherwise I'll make mini-trays for it.

heathbar64 (author)2011-07-15

So, still thinking about this project. I'm a little confused again. You mention your use for it as de gassing silicone for moldmaking. I am familiar with the idea of using a pressure tank to squeeze the bubbles out of a molded item, but seems to me like a vacuum would create bubbles. Am I wrong about this? Can you give more info on that use of it?

The Ideanator (author)heathbar642011-07-16

Vacuums tend to remove all gases and things with low enough (or was it high?) vapor points from the chamber which means that all the gas in said mold *should* come out, however if you have trapped gases, they will expand (they went in compressed at nearly 15 psi from the vacuum's point of view)

I imagine that if you put a carbonated drink inside there, it would de-carbonate (I'd like to see a video of that, I can't find any)

Pazzerz (author)The Ideanator2011-10-23

I know this is OLD, but a carbonated drink is dissolved CO2, like dissolved oxygen in the water that fish breathe. It would probably 'de-carbonate' like you said, but would take a lot longer to do than with just air or CO2 bubbles. FYI

bassman76jazz (author)heathbar642011-07-17

you just pull air out of the silicone before you pour it into your mold. less bubbles means better finish on a part. the silicone looks to boil as the vacuum reaches 25" and then falls back as most of the air in the solutions is extracted.

heathbar64 (author)bassman76jazz2011-07-30

Ok, thanks for the education. I'm into molding stuff so I'm definitely gonna play with this.

Then, if you are pressed for perfection,after degassing and pouring you let the silicone harden/cure under pressure, which serves to compress any remaining small air bubbles. The result is smooth and faultless.

jschumaker (author)2011-07-25

Where'd you find a 24" piece of 6" pvc at Lowe's? All I could find were 10' lengths. Also, any particular reason you used the green pvc?

jlin is (author)jschumaker2011-10-17

if you go to homedepot or lowes, they will cut what ever length you need and sell per foot

jschumaker (author)jlin is2011-10-17

That is great to know.

bassman76jazz (author)2011-07-09

I got it up to 42cm today while degassing some silicone.

the max i have been able to reach is 25" or just over 60 cm Hg

codongolev (author)2011-07-15

my chemistry teacher had a smaller version of this that attached to the sink. he said he used it to draw liquids out of precipitates when filtering.

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