Piston probloms

[turbohacker]

this is my firt piston gun. I have been building pnumatics for quite a while but i cant seem to get this dang piston to work
the pison seals well but when i exaust it only air from behind the pison leaves, the piston will not slam back. when te pressure is relived then the pison will slide back. any suggestions?[/img]

[A-98]

ive had that happen to me, and i couldnt fix it. other people will probably answer your question tho. and ide like to know the answer

[benstern]

Is the piston lubricated? If not it may not move because of friction.
How big is the chamber?

[spudthug]

yes rubber is very tricky to get to move....lube it up wtih gun oil......alot of gun oil if it doesnt work...maybe the inside of ur chamber is rough/bumpy??sand it a bit just to be sure...fine grit sandpaper 250 grit+ only u will rough it more if u use any less grit..

[jrrdw]

Can't really see how much pilot volume you have. Do you get a little amount of air out of the sprinkler valve, or does the whole main chamber empty out of the sprinkler valve?

[turbohacker]

chainber is around the barrel
3 inch outer pipe for resivior and two inch inner pipe for barrel
ps. it is lubed extremly well

[keep_it_real]

I would make a lot more chamber volume. I doesn't look like you have very much. Make sure the piston slides pretty easily but it should also seal pretty well against the pipe.

[jrrdw]

Do you have enough of a pilot chamber for piston to retreat into?

[experament-u2]

this is the exact problem i had a few days ago
i fixed it by adding a oring and cutting the size of my piston down but im not sure how u could do that to urs

[hi]

i had that exact same problem with my first coaxial. the solution is simple, your piston is too loose int the chamber. you need to make it fit better and put a little oil on it and it ill work fine. your piston isnt exactly round, it close, but not quite. it need to be perfecly round and fit in the chamber just right.

[Matheusilla]

I agree with "hi". Your piston is probably too loose. There are many ways to make it fit better, it just depends on what you have to use/work with.

[deusXmachina]

It's too thin to put o-rings around easily, but Ive heard a few layers of duct tape/painters tape work, just make sure they don't come loose and get lodged in the pilot assembly.

[Freefall]

When you try to fire, does the chamber completely depressurize? At first glance, I'd guess that you're leaking too much air past the piston, which prevents the force imbalance needed to drive the piston open.

[tater36]

if i use an end cap for my piston on my first would multiple wraps of duct tape work to let air get past but still work?

[Blitz]

if i use an end cap for my piston on my first would multiple wraps of duct tape work to let air get past but still work?

Dude, start your own thread to ask that.

What exactly is that piston made of? What kind of rubber?