piston probs :(

[experament-u2]

ok i know every one has problem with there pistons but mine doesn't seam to want to pull back when vented now the piston fits perfectly inside the cute and doest need orings or duck tape and seals well against the barrel and even with my light spring removed it wont work

plz help i rely want to get this gun working

the crappy paint below is my basic set up

[homedepotpro]

what is you pilot source and do you have large equalization holes in your piston

[spudthug]

do u have any equilization holes i nyour piston? i know alot about pistons now so if u could post a pic of ur piston, inside the tee,bumper,and pilot, i can probably help u

[keep_it_real]

There needs to be air in front of the piston so it can be pushed back when piloted. By the looks of your design, you just need a smaller barrel.

[experament-u2]

my pilot source is a 1/4 ballvalve
i have a pin size equalization hole in he piston
my bumper is a old sprinkler valve spring

heres the hole piston


heres a blurry picture of my piston


piston inside chute (old piston)



the chute inside tee


inside the tee

[hi]

can you tell us that kind of tee its built into? what size the everything?

[experament-u2]

There needs to be air in front of the piston so it can be pushed back when piloted. By the looks of your design, you just need a smaller barrel.

im using a bit 3/4 poly pipe for my barrel and the id is allot smaller than the od

can you tell us that kind of tee its built into? what size the everything?

the tee is 20mm pvc and the end cap is 25mm

[spudthug]

ur barrel isnt halfway through the tee is it? it doesnt look like it and that is ur problem..

Edit: also the sealing face of teh barrel needs to be smaller than the id of the tee so there is air to force it back

[experament-u2]

ur barrel isnt halfway through the tee is it? it doesnt look like it and that is ur problem..

Edit: also the sealing face of teh barrel needs to be smaller than the id of the tee so there is air to force it back

im pretty sure the barrel dosnt need to be half way through the tee

and the sealing face of my barrel is smaller than the id of the tee

[Velocity]

If your barrel is halfway through your tee, it will make it a LOT easier to seal.

[keep_it_real]

Do you have any air in front of the piston?

im using a bit 3/4 poly pipe for my barrel and the id is allot smaller than the od

The OD needs to be smaller also to allow for space so the piston can be pushed back.

[experament-u2]

Do you have any air in front of the piston?

im using a bit 3/4 poly pipe for my barrel and the id is allot smaller than the od

The OD needs to be smaller also to allow for space so the piston can be pushed back.

oh now i under stand,
is there any way i can modify my design to allow air around the front of the piston

hears a better picture of my set up

[hi]

if that is an accurate picure, then the problem is that there is no air in front of the piston to push it back. try using a tee that is a little bigger.

[experament-u2]

if that is an accurate picure, then the problem is that there is no air in front of the piston to push it back. try using a tee that is a little bigger.

iv alredy constructed this gun and the 20mm tee is crucial in my overall design

is there anyway i can make some space in front of the piston? maby remove some

[hi]

doubt it. think you just need a slightly larger tee.

you might get away with drilling holes, but that would weaken it, so i dont think its worth it.