Picture of Homemade Check Valve (one-way valve)
I made this at home after seeing that they are 15-20 dollars online and even more expensive at stores. I made it for around 6$ and had some of the stuff around the house. It worked perfectly for my compressor.

Step 1: Parts Needed

Picture of Parts Needed
2- brass hose barbs (whatever size you need for air hose you're using) 1- brass coupler (same thread size as hose barbs) 1- pencil eraser 1- spring 1- rounded thumb tack 1- o-ring Super glue

Step 2: Determine Air Direction

Picture of Determine Air Direction
Thread one hose barb into coupler. I made an arrow on mine to show air flow.

Step 3: Make Air Restrictor

Picture of Make Air Restrictor
Put pencil eraser into the spring and insert rounded thumb tack.

Step 4: Glue O-ring

Picture of Glue O-ring
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Super glue o-ring onto other hose barb. Make sure it is slightly smaller than the rim of the barb.

Step 5: Assemble Parts

Picture of Assemble Parts
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Put spring into coupler and screw in other hose barb. Make sure the thumb tack's rounded edge is facing the o-ring. This will create a seal when air tries to return to the source. You will have to experiment with the spring and torque of the hose barbs depending on the amount of air you are using. Stretch or compress the spring if needed. I tested mine up to 150 psi with no backflow. This is for inline application, but replace one barb with a nipple if you want to direct-thread it to a tank or other application.
Bill WW1 year ago

Very clever, the O-ring seal.

guicarlorobelli (author)  Bill WW1 year ago
Thanks! Sorry for the delayed response. I'm just now seeing this for some reason.
diydonut1 year ago

Interesting concept. Sometimes you just have to jerry rig if they don't make the right sizes that you need. You may want to look into upgrading to a ball bearing instead of the pencil eraser and tack though.

guicarlorobelli (author)  diydonut1 year ago
Thanks for the feedback. I looked around for a ball bearing, but thumb tacks were more readily available. It works great.
jcsevero1 year ago

boas parabéns trabalho

johnlomax1 year ago
thanks for the info, i tinker with odd projects (water and air) and I'm sure I'll use your idea for a few of my experiments.
guicarlorobelli (author) 2 years ago
Thanks for the info!
rimar20002 years ago
Very clever design, and well worked.
guicarlorobelli (author)  rimar20002 years ago
Glad I could help.
cheap brass barb fittings:


tlevy12 years ago
nice idea, im looking for the same idea but for my fuel line in my car, any ideas must take low pressure to open but still seal to hold fuel in the line when car is off.
guicarlorobelli (author)  tlevy12 years ago
I think this design would work with fuel if you knew how much pressure is needed and tested it with air first. There is a lot of trial and error with the spring in this design to get the right pressure. Also, I would check the corrosive properties of gas and the parts being used. Should be okay with brass I think.
grunthos2 years ago
Nice!  I wish I had seen this (or thought of it) when I was putting together my air compressor manifold at home.  I needed several, and I would have loved to save a few bucks.  My setup: http://www.bolis.com/amillar/tools/air-compressor-tanks
guicarlorobelli (author)  grunthos2 years ago
Nice rig. I'm a big advocate of building things myself instead of buying them. Thanks for looking!
Nice solution, like you said you can get them online, even in smaller sizes, but for a bang for the buck you found an elegant solution. Good job and thanks for making this ible!
guicarlorobelli (author)  boogiemanspud2 years ago
Great idea. I'll use it on my water pump
guicarlorobelli (author)  andrefellows2 years ago
Let me know how it works with water. It seems like it will work...
ray742 years ago
That is awesome.
guicarlorobelli (author)  ray742 years ago
Thank you
fozzy132 years ago
This is fantastic! I hate how expensive check valves are also, but was never able to make a quality, perfectly airtight alternative. Thank you!
guicarlorobelli (author)  fozzy132 years ago
You're welcome. Let me know if you are able to test it beyond 150psi. That's all my compressor is capable of.