SpudFiles

Are all PVC unions pressure rated? I found a 2" union at United Hardware for $8.99, it's dark gray. The same Union on http://www.mcmaster.com costs about $20, if this is good for pneumatics I'm going to buy a few. I forgot to check if it had a pressure rating on it.

its proably pvcII(sch80) mine looks like that(dark gray) and it says pvcII on it, so my scientific conclusion is that yes the cheap one is pressure rated

Cool, next time I'm there I'll buy one. I work across the street from their.

Buy like, all of em. That's a very good price. I may want you to send one to me. I need one and I am having issues finding a 2" sch 80 union.

I don't really like mailing things. Check if you have a United Hardware by your place. It's a supplier and not a store so things are a lot cheaper, being a supplier also means they're loaded on parts. When I went there, they had boxes full of pipe parts that they didn't have room for.

P.S. What are unions normally for? Are they for filters? Something about screwing 2 pipes together?

It's just for connecting two pipes toghether with an air/liquid tight seal, no pipe rotation needed, and allows for a tight fit with no need to pull the pipe away from the other pipe.

Let's say you want a good connection from one spot to another spot exactly 2 feet away and niether connection is able to move at all. Unions allow each joint to connect to the 2 foot bridge pipe at the same time so there's no need for reverse threads or cramming the bridge pipe in to fit.

what! last time i brought a 1 inch sch40 union it cost me $20 oh f***

Wow these things must be really cheap. I might check them today after work, I just have to cross the street. i'm gonna use one of these for my first pneumatic. I'm gonna try and use this idea.
http://www.spudfiles.com/forums/viewtopic.php?t=1842&

P.S. Couldn't you use a burst disk for an exhaust? You would get an extremely fast exhaust. Someone should just take like 5 piston valves, have them exhaust in chain reaction. I wonder if that would be cool. Boom, Boom, Boom, Boom, KABOOM! Oy my back!

The advantage of a faster opening pilot valveis mainly consistancy, and there should be no percivable inprovment in that from such an exsesive firing chain.
Using a QEV as a trigger is good enough.

As to using a burst disk as an exhaust, if you are going to relinquish control over the time of launch, you might as well just get a 2" union - you'll gain preformance and save money.