soleniod plugs
 

the holes that the solenoids release air from need to be covered so nothing gets in, but air can get out.. any suggestions??

If I understand this correctly, you're afraid of "backdriving" a pneumatic actuator, when it's been previously energized?

To my knowledge, you don't have to connect the exhaust ports to anything, including a one-way flow valve (I'm not too learned in the terminology, quite yet).

And, if it didn't come in the kit, and wasn't one of the three custom actuators your team ordered, you can't use it in the pneumatic system for your robot.

all i am talking about is some kind of plug used to let air out and not let stuff like metal shavings in... that could be bad... for example the technocats use plugs that look like airator stones from a fish tank but on screws.. (team 47 ,where do you get them?)

I can't seem to find what you're referring to, in the TechnoKats' pictures.

If you're going to be generating metal shavings during competition, you have bigger things to worry about. If you're just trying to keep things clean and safe while you're working on the robot, cover them with shoptowels, someone's shirt, or whatever else you might have, on hand.

You shouldn't need to cover the holes. If a shaving get's in, in most likely won't go into your cylinder, if it does.. it still should be traumatic.

If you are worried about stuff coming in, take a normal plug (for putting hose into), stick it in there. Air will still be able to travel out easily and nothing will come in. You don't need a tube either.

If you are still paranoid, stick a tube in it and run it to a shielded place. Or better yet, just shield your solenoid. As Foto said, shop rag, shirt, whatever. When it comes competition time, throw something else over it, or wire-tie the shop rag on.

One-way flow is permitted by a "check valve", akin to elecronics' diode.

The 'aerator' of metal balls that looks like an airstone is sometimes called a "muffler", since by increasing the area through which the exhaust flows, and by calming its turbulence, the lous "Pshhh!" is quietened.

suggetion - do your machining on another planet, so you get no shavings near electronics or pneumatics. :D