Instructables
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.
 
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Step 1: 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           (www.estreetplastics.com)   $12
2 - 1/ 8" x 12 " x 12" neoprene sheets   (www.smallparts.com)           $20
1 - vacuum Aspirator                                 (csrscience.ecrater.com)      $25
1 - vacuum gauge                                     harbor freight                            $13
1 - 3" x 3/8" air hose                                  harbor freight                            $4

                                                                                                                                                                 Total = $90


Step 4: 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

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.
KDS44449 months ago

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.

bassman76jazz (author)  KDS44448 months ago
that is the pump. it uses the a garden hose to pull vacuum.

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 KDS44444 months ago

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.

aspirator-definition.png
KDS4444 Hieu10 days ago

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?

BruceC2 Hieu16 days ago

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

bassman76jazz (author)  KDS44448 months ago
http://en.m.wikipedia.org/wiki/Aspirator_(pump)
nice kids !…
bassman76jazz (author)  vincent75201 year ago
thanks...
rf3 years ago
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)  rf3 years ago
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.
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.

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.
rimar20003 years ago
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)  rimar20003 years ago
i bought it at
http://csrscience.ecrater.com/p/11338240/aspirator-with-garden-hose-adapter
you can get it with or without the hose adapter.
there is a detailed description there.
2011-07-08 15.11.53.jpg2011-07-08 15.17.30.jpg
Thanks, but I live in Argentina. Maybe it is simply a Venturi tube, very easy to do.
I did a bit of searching and found this... it may help you.

http://www.sciencemadness.org/talk/viewthread.php?tid=437&page=2

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

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.

Thanks for the info.
bassman76jazz (author)  rimar20003 years ago
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.
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
http://www.accoya.com/technology/
http://www.accoya.com/
Titan Wood Inc.
modified wood by Accsys Technologies
http://www.ufpi.com/product/accoya/index.htm

Brug = Bridge Akkerwinde = name of a road
Sneek = name of a city in the Neatherlands
Brug Akkerwinde
Akkerwinde Sneek
http://www.bsbstaalbouw.nl/bruggen
http://www.achterboscharchitectuur.nl/page.php?id=97
http://nl.wikipedia.org/wiki/Houten_bruggen_bij_Sneek
(for me Google Toolbar can translate Dutch to English)
Thanks for this abundant info!
Hmm.... I wonder if this could be used to construct a home food freeze drying device.
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.
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?
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.
heathbar643 years ago
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?
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)
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)  heathbar643 years ago
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.
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.
jschumaker3 years ago
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?

if you go to homedepot or lowes, they will cut what ever length you need and sell per foot
That is great to know.
bassman76jazz (author) 3 years ago
I got it up to 42cm today while degassing some silicone.
bassman76jazz (author)  bassman76jazz3 years ago
the max i have been able to reach is 25" or just over 60 cm Hg
codongolev3 years ago
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.
meyotch3 years ago
Yay! It sucks! Just kidding! (or *am* I?)

Great instructable. I happen to have a lovely glass bell jar without the vacuum base. I need a vacuum source about once a year for one of my projects and now I am inspired to build a base and make it whole once more.
bassman76jazz (author)  meyotch3 years ago
nice... i have always wanted a bell jar. they are so expensive
These days I'd probably just buy a bell jar on ebay: for $40 - $70 you can get something MUCH better than a homemade glass bell jar...
You can make your own bell jar from a large glass bottle (I used a 2 liter glass juice bottle). Cut the bottom off the bottle by scoring around the circumference with a glass cutter, then touch a red hot wire to the scored area, and the bottom will come off (I used a small piece of nichrome wire heated with a low-voltage power supply). Use progressively finer wet-and-dry sandpaper on a flat plate under water to smooth the cut edge of the bottle.

I used a thick aluminum plate and a gasket cut from a rubber sheet to use with the "bell jar". At the time I was attempting to "sputter" metal films using high voltage.

You should be careful when the bottle is under vacuum, since if it breaks the glass could fly towards you. In practice, glass is quite strong, but I'd still recommend the thickest bottle you can find.
Indeed they are. I felt very fortunate to inherit this from the estate of a science-dude I was close with. He had accumulated a lot of crap during his career and quite a few little treasures.

The Life Lesson: Always be nice to crap-hounds.
I too use vacuum too infrequently to justify a proper pump. I get vacuum from my air compressor. I just unscrewed the air intake filter and screwed in a hose barb. then I just open the tank drains so it will run continuous and hook the vacuum hose to the inlet. I don't get 30" but close enough for my purposes.
Great Instructible!
I wonder where you came up with the vacuume asparater?
It's a venturi that creates the vacuum, the same as a car carburetor, that's how the fuel gets from the bowl into the throat of the carburetor. They sell vacuum generators but the only way I've seen them is compressed air to vacuum.
If you came with on your own your a genius!

Alan Hale
Fluidpower Specialist
bassman76jazz (author)  Skipper3333333 years ago
its a common lab tool used for as an easy source of vacuum. I just wanted a cheap vacuum chamber an thought it was worth a shot. it has its limits but its great for hobby use. I'm still testing to see how far it will go. i got to 45cm Hg today.
You all confused me for a bit there. I'm used to working in inches Hg, and Y'all are talking cm. 45 cm is only about 18" which aint very good. I did better than that with my rigged air compressor mentioned earlier.
bassman76jazz (author)  heathbar643 years ago
but i built it with a chamber for less than the price of an air compressor.
Sorry, didn't mean for my comment to be critical. I had the old compressor for other purposes. It is a cool project. I think I'll build a smaller one.
I did a little google search for the aspirators and found many of them claimed 28" or 73cm draw with 60 psig.water pressure.
tmarosites3 years ago
Hello bassman,
Have you tried to hook it to a pressure washer?
That should jack it up quick since the draw is based on the water speed.

great tool and instructable
The draw is actually based on the vapor pressure of water at the temp of the water stream. The colder the water, the deeper the vacuum possible.
Hmmmm, I can see that the colder the water the , the deeper the vacuum possiable because the water is more dense ,like in a carb on a car,  . Now when you add on a turbo charger It increase the air but it also increase the temp so this is why it is best to cool the air , But it is the spead of the air that increase the pull, just as the increase in the water speed should increase the pull on the vacuum much more then the temp.
Could you tell where i am wrong.
Thanks
Terry




Pressure certainly does help to a point, but the problem is that when you start getting a decent vacuum formed, the water will actually boil. The water is then in a gas form, and will end up in your vacuum chamber, decreasing the vacuum just like a leak of air would. Keeping the water temperature low makes it take more vacuum to cause the water to turn to a gas.

If you get a really good electric vacuum pump (piston, rotary vane, etc.) and chamber, you can make a cup of water inside the chamber "boil" so much that it freezes. Even at room temperature, water is full of really hot molecules and really cold ones. It's the average of those hot and cold molecules that we call temperature. When you reduce the pressure, there's no air molecules pushing down on the surface of the water anymore, so those hot water molecules are able to leave the surface of the water easier, and the colder ones are left behind...lowering the temperature. Neat :)

There's a bit of info on Wikipedia about aspirators here: http://en.wikipedia.org/wiki/Aspirator
bassman76jazz (author)  tmarosites3 years ago
i have not. I think i might want to upgrade the acrylic to 1/2" for that.
RickO53 years ago
What sort of volume of air will this pull? Obviously CFM varies with the vacuum level, but do you have an idea? I guess I could work it out with a stop watch, your video, and some basic math, but maybe you already have?
bassman76jazz (author)  RickO53 years ago
I'm not sure. something to figure out.
DaveB133 years ago
For safety you may want to look up PSI strengths of the materials you are using, or at least stand back / wear heavy clothing / face shield when pushing for max vacuum, out of hand I doubt you have a problem, but I think you should check. 45cm Hg seems like a lot. Perhaps their is an online coverter / advice to translate between the pressure formats.
Nyxius DaveB133 years ago
shouldn't be a problem. Most schedule 80 pipes are rated for at lease 60 psi. The most he could possibly be getting is around 10 psi. But that is still a significant amount of force. seeing as how you were able to pry the plexy off I doubt you are getting more than 5 or 6 psi.
Pipes can handle less psi for vacuum than they can for positive pressure, because vacuum puts the walls under compression rather than tension, so they can buckle. (Think about how a soda bottle easily collapses when air is sucked out of it, but handles the positive pressure of the soda easily.) Still, because it's plastic, the failure mode is just buckling rather than some sort of dangerous explosion, so there's probably not much danger in pushing the limits.
bassman76jazz (author)  DaveB133 years ago
45cm is not that much, the parts i use can go much farther, acrylic and pvc are very strong materials. there are no sings of weakness even up to 60cm.
XTL3 years ago
Another material that works well here is an old car tyre inner tube. it also fits over the tube and stays on easily.
Nyxius3 years ago
I usually us a shop vac, milk crate, and garbage bag to degas my silicone, but yours looks pretty good.
Skip3 years ago
Could you please explain how actually works?
bassman76jazz (author)  Skip3 years ago
the vacuum asparater is a common lab tool you can find it at most laboratory supply stores. it works just like the venturi valve systems but instead of using compressed air it uses water. the higher the water pressure the higher the vacuum. you can actually hear it begin to suck air when the chamber is closed.
I got this one at www.csrscience.ecrater.com
Aspirator. Not a spelling nut, OK, I am, but I'm only correcting the spelling for the purposes of people searching for it.

Very nice instructable, BTW.
bassman76jazz (author) 3 years ago
I just read the
Vacuum Infused Fruit Cocktails Instructable
I'm going to try it out with my new vacuum chamber this weakened
bassman76jazz (author) 3 years ago
I have had it above 52cm but the washing machine was on at the same time so I think it will go even higher. I think 60cm may be the limit. ill just keep testing as see what it can do.
Cool. You might want to set it up so the water is collected instead of wasted.
bassman76jazz (author)  rocketman2213 years ago
good Idea, i have just used it when my grass needs water. I does not run for more than a couple of minutes and does not put out a lot of water once the vacuum starts to build.