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Make a manual vacuum pump for under $20 by converting a bicycle pump

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A vacuum pump is just an air pump that you use for sucking rather than blowing. You can convert an old-fashioned "floor pump" ("bike pump") into a vacuum pump that can take over 75 percent of the air out of something. That's several times as strong as a vacuum cleaner's pull, and three quarters as strong as the best possible vacuum pump.

The net atmospheric force on whatever you evacuate will be over 11 pounds per square inch (or over 1500 pounds per square foot), which is enough for many tasks requiring vacuum.

(For those of you who are not metrically impaired like most of us in the U.S., that's over 7700 kilograms per square meter.)

Some examples:

(1) Vacuum pumps made this way are in use around the world, in non-industrialized areas, for vacuum packing food. (Especially to save seeds for the next year's planting, by killing bugs and preventing germination. See http://www.plenty.org/soy/vacuumpump.html )

(2) A manual vacuum pump can used to make a "vacuum press" to clamp laminates together with a ton or more of force while the glue sets. (A smaller manual pump, designed for evacuating wine bottles, is often used for laminating skateboard decks, using a commercial vacuum bagging kit from Roarockit called the "Thin Air Press". Our bigger pump pulls about as hard, but requires considerably less pumping.) It can also be used for vacuum bagging composites like fiberglass, to squeeze out excess resin and make stronger, lighter parts.

(3) You can use it with a vacuum former, to form thicker plastic sheets than you could with just a vacuum cleaner. (Doug Walsh shows how to apply this to vacuum forming in his book "Do It Yourself Vacuum Forming for the Hobbyist," available from http://www.build-stuff.com )

(4) You can implode various things with it, or attach it to a vacuum chamber and expand or explode things in the chamber; that's often fun and/or instructive. (Try Peeps.)



The vacuum generated is not strong enough for some tasks, like evacuating refrigerant systems or degassing difficult-to-degas liquids. For those tasks you need a pump with more leverage, that takes almost all of the air out.

A plain bike pump is just a piston pump rather like a syringe, with a rubbery disk sliding in a cylinder. Drawing back the disk sucks air into the cylinder, and pushing it in pushes air out.

To make this syringe-like thing work as a pump, sucking from one place and blowing to another, two "check valves" (one-way valves) are used. One lets it suck in from an air intake, but not blow out the intake. The other lets it blow out the exhaust, but not suck in from the exhaust.

Unlike most piston pumps, a bike pump uses the rubbery disk both as a piston and as one of the check valves. When you pull back on the pump, the disk flexes inward and allows air around it, into the cylinder ahead of the piston. When you push inward, the disk is stopped from flexing the other way by a metal disk (like a big washer); its edge seals against the inside of the cylinder, so that when you push it down, it compresses the air in the cylinder and forces it out the exhaust.

(There's a normal check valve at the exhaust, to keep it from sucking the air right back in on the upstroke, and more air flows in behind the piston through a hole in the cylinder top.)

To convert the pump, we'll need to do two things:

(1) Reverse the piston disk and the metal disk that backs it up, so that it seals on the upstroke (to create vacuum) and flexes on the downstroke (to let air around it and out of the cylinder).

(2) "Reverse" the exhaust check valve, so that it lets air in but not back out, and we can use the old exhaust connection as the new air intake. Actually, it's usually easier just to remove the check valve, and replace it with one that does the right thing, so that's what we'll do.

To make it easy to do both of these things, we'll want a simple, cheap, old-fashioned bike pump with no frills (like a pressure gauge) to complicate things.

(If you want a small electric vacuum pump, have a look at my other instructable on converting a 12V "tire inflator" air compressor: http://www.instructables.com/id/E791HNXF23Z39P6/ )

 
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shortshift6 years ago
Thank you for posting this recipe! I was able to draft a vacuum pump quite simply and with the bagging equipment found at Aerospace Composites, I put together a pretty good system for some fiberglass layups that I'm working on for my motorcycle project.

Here's a fuel tank prototype that I've been working on. I used a check valve from what appears to be a fish tank setup (ACP was the supplier). 1/4" neoprene tubing.
IMG_1369.JPG
drcrash (author)  shortshift6 years ago
Very nice. Keep us posted. Maybe you should do an Instructible on low-end vacuum bagging. I think a lot of people would be interested.
drcrash (author)  drcrash11 months ago
And here's shortshift's Instructable on Basic Vacuum Bagging:

http://www.instructables.com/id/Vacuum-bagging-basics./

Cool.
ya mean that hasn't been done yet? wowzers. I'll see about putting something together. Of course I'd cite your vacuum solution as a means to the end :)
drcrash (author) 7 years ago
Apparently this instructable is the "hack of the day" over on www.hackaday.com; cool. A question came up over there about reversing the exhaust check valve rather than replacing it with the one from McMaster-Carr. You COULD do that, and I'm pretty sure it would work fine. (With the Slime 2060-A, anyway.) You could clean the oils off the exhaust hose fitting and the place it attaches, and epoxy it in backwards, with the hose barb pointing into the threaded hole. (You might need a spacer such as a large nut to keep the hose barb from sticking all the way to the bottom of the threaded hole; I'm not sure.) Then you'd need to epoxy a new hose barb on top of that. (Hot glue would probably work, if you duct tape the hose to the cylinder near the joint, to avoid stressing the joint if the hose gets pulled on.) That would let you make a vacuum pump for around 13 dollars with stuff from the auto parts store and a home improvement store, and not have to wait for mail order.
DanTDM3 months ago

Even ones with a metal shaft usually don't work! So, I just used my pump as a portable source of air for my air gun

Skymeat7 months ago
I love it! Taking an old one apart now.
can anyone help me build a vacuum pump using a foot air pump with pressure gauge?
WazIt1 year ago
Thanks, I'm going to try it, but I'm going to use a tire valve stem with my vacuum chamber so I can use the hose that comes with the pump
WazIt1 year ago
Thanks, I'm going to try it, but I'm going to use a tire valve stem with my vacuum chamber so I can use the hose that comes with the pump
wily701 year ago
Hello, how much Hg or bar can I expect from such a vacuum pump?
thanks
xfrench1 year ago
Hi. Thanks for the inspiration. Any advice for how to use a found pump that does have a gauge? It's the first one I've found thrifting, and would be nice to put to use...
Geoluhread2 years ago
Will this effective for a physics experiment? I would want to use this for a Bell in a Jar experiment for our project. I've tried this already I don't know if there is something wrong but the air sucked is very little. I used an aquarium check valve because its hard to find a check valve like yours in our place. I've searched for every autosupply and hardware store and they don't have it.
gatan5 years ago
hellooo all
question -0,6bar=....."mercury
help me, how to convert :) thank..
Esmagamus gatan3 years ago
onlineconversion.com does all you need.
Derin gatan4 years ago
-17 in Hg
arisecute gatan4 years ago
Please go to - http://joshmadison.com/software/convert-for-windows/ - you would get a free conversion software for download. Madison is a great man doing a great job.
Use Google. Type: "-0.6 bar in mercury" and press "enter". That works for most conversions, such as "3 feet in meters", "5 pounds in kilos", etc.
Hi, i recently discovered a how-to on building a kitesurf board. It requires vacuming to (i guess) squash the fibreglass cloth onto the core, ans seal it all nicely. I was a little put off by this as i have no means to do it, (conventional vacuums are too expensive to buy just to make a board) but now im wondering if it is possible. Would the vacuming capabilities of this pump do the job and pull all the layers in enough to hold it together strongly?? any help on this would be awesome and much appreciated
Find an old refrigerator thrown in the trash.

Take the compressor with control box out by cutting all the tubing. Fit a power cord on it and you'll have one side sucking air, other blowing. There's your vacuum pump.
Eddie_T3 years ago
I confess I am somewhat of a nut, my wife has been hospitalized on occasion and I collect the oxygen and IV tubing when it is changed. Just for kicks I made a small vacuum pump using the tubing, two of the locks that permit injections into the IV line and a syringe. It might be used to take the air out of a wine bottle or one of those 2.5 inch cylinder thingies.
CHRISPB5 years ago
Does anyone have a suggestion on makeing a manual pump that could, after several priming pumps, begin to generate a constant airflow of say 10-15 L/minute? Would you use a flywheel or double valves?
Goedjn CHRISPB3 years ago
Build a double-action bellows, or two sets of foot-bellows, feed the output into a big sack, and put an appropriately sized rock on the sack. This is essentially how a pump organ works.
The SYNer4 years ago
would this pump work for a particle accelerator
no a particle accelerator needs a near perfect vacuum something no simple hand pump can get near. to make a a vacuum for a particle accelerator you need a cooling system near absolute zero to literally freeze the air solid on the cooling pipe making it a better vacuum than space.
Wafflicious5 years ago
My cup imploded(I think that's a word..)
Yes, it is a word and means according to the built in dictionary on my Mac, "verb, to collapse or cause to collapse violently inward"
MadMonso3 years ago
Hey, although McMaster doesn't seem like you can do direct links you can, just do "#"{PartNumer} no "" or {} so Check valve: http://www.mcmaster.com/#6079t53 That one specifically just does a highlight on a page so I'd still include the part number in your description. Nice job.
wenui4 years ago
Hi,
How do you use like valve?
Thanks
vernonen4 years ago
G'day all,
I am about to build a vcuum bubble to use as a VTOL transport  and OH hoist. I needed an economical vavuum pump which would pull out 80% of the air. Has anyone tried this? I will keep posted.
Will this work well for making neon lamps and other such devices?
Derin6 years ago
lol,"if the pvc hose gets off you are hosed",oh the irony
tradergordo6 years ago
I was about to build one of these, thanks for the instructible, but I just discovered that Harbor Freight now sells a vacuum pump for just $10.99 that pulls 28.3" mercury! I can't build one for that cheap, and it creates a very strong vacuum all with standard fittings so you can easily attach whatever you want to it. Can also be used to service any time of air conditioner. Anyway, just thought others reading this thread might be interested. It does require an air compressor so its only for people who already have an air compressor.
HF vacuum pump

They have two other models which are very similar but have different fittings.
Come to think of it - I wonder if someone without an air compressor could just hook a normal (NOT reverse flow) bicycle pump to the air inlet of this HF vac pump and create the vacuum manually, this should be a very easy mod. But I guess it would basically just be the equivalent of using the thing as a giant check valve :) I guess if you live close to a harbor freight store it might be worth trying.
Mine made a scraping noise,is that a prolem? Also I don't reccomend an aquarium check valve.
drcrash (author)  Little Dreamer6 years ago
Could you give me a little more detail... ? Did you use the same pump? Did it make the scraping noise right away, or after a while? Have you unscrewed the top and pulled out the plunger to see if there's anything obvious wrong?
Same pump, and it made noise right from the start. A little WD40 helped, but I probably need a higher viscosity.
We work in masonry and we now use pam (veggie oil) on our wet saws sliding tables to make them slide better. Pam is way better than wd40 and stays on way longer too. Might be good for the bike pump too!
Actually I pulled the pump out and no scraping. I'll watch it.
drcrash (author)  drcrash6 years ago
Just to clarify... mine makes about the same noise as a vacuum pump as it did as a regular pressure pump. No metal-to-metal scraping noises. You can hear the shaft rub against edges of the hole in the plastic cylinder top, but I wouldn't describe it as a "scraping" noise, exactly. If you've got something that sounds like metal-to-metal scraping, something is probably wrong, but I can't tell what without more information.
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