Help with twin chamber/valve "T-shirt Launcher"

[nicholai]

yeah two sprinkler valves could run you from $30 to $50 and wouldnt be worth it, i mean you could experiment making a few improvised piston valves inside a 2" tee and make 3 of them for that cost, making the piston itself is real easy and cheap provided you do some research into various piston designs. Now a homemade piston valve inside a 2" tee isnt going to be anything close to a supah valve but it would outperform a pair of parallel sprinkler valves and be cheap enough to make a few mistakes along the way.