Pneumatic Support

Hello! My team was able to successfully mount and test our pneumatic kit, however, our pistons don’t react in a synchronized manner and we don’t know anything about its different components and have many doubts about its capabilities.
For instance: I’d like to know if we are able to control the amount of pressure that each piston recieves, I’d like to know why air is released in the part where cables are connected and how to minimize that, and I’d like to know if we could costumize our pneumatic system.
Does the kit have any kind of documentation?


Im not sure i understnd you completely, if you are having problems with the pistons perhaps you could post a link to a video?

If air is escaping where it shouldnt, there is probably a leak at the tubing connections. This problem is usually an easy fix. Make sure that the ends of the tubing have nice flat cuts perpendicular to the tube. Air generally leaks out from here.

And yes, you can control the pressure reaching the pistons. You can use the pressure regulator for this.


Pneumatics are a great kit to add onto a robot for the extra utility – don’t ever ditch it!
Here’s the guide that comes with the kit, pretty informative actually. Here

Some things to know, which may answer some of your questions:
The pressure each piston gets is completely dependent on both the psi of your reservoir, and the use of the pressure regulator (blue and white tube connections). Mess around with the knob on it until you find a consistent pressure you like and put washers in to keep it that setting. Of course, you’ve only got one pressure regulator to play with.

The connections from tubing to pistons should be tightened with a wrench, so they can’t be unscrewed by hand. This prevents a lot of leakage. In general, check that every fitting that can be screwed on is tight, and that all your tubing is leakproof.

Something you can do to check for air leaks is to run the system WITHOUT the solenoids under a tub water. Air shouldn’t leak out except when the pistons retract.

Don’t stick your pneumatics kit underwater! Take a small amount of water with a little liquid soap in it and put small drops on all your hose joints. Any leaking air will blow little soap bubbles. This also has the advantage that you can test your system while on the robot. I’m pretty sure sticking your whole robot in a bathtub would be a Bad Thing (at least until the VEX Underwater Game is announced).

You went there!!! NOOOOOOOOOOOOOO!!!

Have fun with rust mate, those things are not always Aluminum.

As for the OP I’m not 100% sure what your asking. Are you asking how pneumatics work in general or why something is leaking. And are you asking how to sync pistons?

  • Andrew

Sorry if I was unclear, I posted the last post in a hurry. I mostly asked for documentation. For some odd reason, I never really saw that guide, although my team already has more than one kit.

I still have two doubts. The pistons we have do not react at the same time, in fact, one of them reacts about half a second afterward the other. However, the overall mechanism works nicely when we put it all together, so I don’t think it’s that big of a problem. This might be related to the rest of the mechanism and not with the pneumatics.
My second doubt is that air is released on the Solenoids, however, this is not because of the tubing, the Solenoid seems to have some holes that release air when the pistons are in a certain position, does anyone know how to prevent this from happening? I can’t provide more details right now since I’m home.

Thanks for all your replies and I hope I was clearer this time.

Are you trying to recycle your air?

The solenoids need to exhaust air for the pistons to work properly. Otherwise it becomes a battle of forces inside the piston/solenoid and the piston efficiency is severely dropped, Instead of doing ~12 pounds out it would be reduced to maybe like 2 pounds of outward force (total guess).

Pneumatics are a great way to add extra motion to your bot, believe me. I understand people skepticism with them but fact is they are used in lots of applications that need to be WAY more reliable than High school level robots. Learning how they work now is a great thing to do also. Out of everyone in my office that I work at I think like 2 people maybe 3 know how air works (one of them being me)

  • Andrew