SpudFiles

1" fittings fit perfectly in 1.5" sch40 and when I say perfect... I mean perfect. Yes, that means caps too. I would recommend using a coulping and 2 spig plugs so that your neoprene can have a nice flat surface to aid in the sealing of the valve. The length of the coulping is also a nice length for the piston and by using 2 plugs... you reduce the dead volume that you have to pilot.

Milk caps fit inside 1.5" pipe, just screw 2 or 3 together.
I took a D or C cell battery and wrapped it in duct tape until it fit with half of a rubber ball glued onto it.

why have you made 4 topics on pistons today?use the f'in search tool all of your questions can be answered in one topic or by searching for 5minutes.

neoprene is a fabric isnt it?

kk thx
!!!!!!!!!!!!!!!!!!!!!!!

No it is rubber. It can be turned into thread and cloth made from it.

I use rubber sink stoppers.

Like Spud Stuff said, neoprene is a rubber but can be used as a fabric like in waders.

Any hard but yielding rubber will do. Neoprene can be bought as gasketing sheets in your plumbing section. Quick caps from the same section works well.

do u have to put a spring behind the piston to pull it back when u let the air out from behind it?

does anyone know ive been searching for like an hour

No, you don't have to use a spring. One of the more talented designers never uses springs. However, you can use one, it depends on the OD of your piston vs pipe ID. This is all available via the search engine.

wheres the search engine?

Right below the login button!