2 vs 1 Reservoirs for Pneumatics

Hi, my team was wondering if we should buy 1 or 2 reservoirs for our robot this year. Our team is considering buying pneumatics for expansion and additional power to our catapult during the autonomous period. We were wondering if we could get away with buying just one reservoir, or if a single one would not have enough PSI.

Personally, I would suggest buying 2 pneumatic kits seeing as they come with 2 pistons in each making it so you can have 2 pistons for expansion, and 2 pistons for your catapult.


We were planning to buy just the pistons and the reservoir separately from another site, because they are not in stock with vex right now.

PSI is not a matter of how many reservoirs you have, kinda. If you have 1 reservoir pumped to 100 psi vs 2 connected reservoirs pumped to 100 psi they both will output the same amount of force. This is beneficial for expansion since it is only being used once per match and can them be refilled. Same goes for a catapult, if you are only using the pneumatics for shooting from the autonomous then 1 reservoir will work just fine. If you are using pneumatics during the match a lot then having 2 reservoirs will help as you will get more actuations out of your cylinders and the higher pressure will last longer.


1 will be just fine, but I would personally get two if you have the budget for future years.

I just bought some and only got one because of a budget, it’s only for endgame anyways.


:+1: We plan to buy the pneumatics only after and if we qualify for states, so it fits into our budget. I will consider buying 2 for future years.

Go ahead and budget for a 100’ roll of tubing and some of those weird little (4mm???) nuts the end of the shaft requires.

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Yeah our team got really annoyed by those little nuts as well, they were easy to lose and didnt remain tight over time. Does anybody have a better way of securing things to a pnuematic?

Put 2 nuts back to back and tighten against each other slightly Will NOT come loose, guaranteed.

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Here’s a source for the #6-40 nuts that go on the rod end of the air cylinders. McMaster-Carr A 100 pack should hold you for a while. As for calling an air cylinder a “pneumatic” (or worse, a “piston”), this meme is appropriate:
Dankest Vex Memes? - #4813 by kmmohn

Well I don’t know if I’d call it better, because it kinda ruins the threads on the screw but you can use a shaft collar and a regular screw to attach things sideways to a pneumatic. Another option is to by some nylock nuts for it, which is what our team uses.

If you use nylocks, you have to CAREFULLY hold the shaft using pliers with some padding wrapped on the jaws to prevent damaging the shaft.

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