Piston valve not sealing (Pictures)

[Matt_NZ]

This is my first spud gun (attempt) from stainless steel pipe fittings.
The piston is just simple hot glue housed inside a 3/4 tee have a look at the pictures and see if you have any theories as to why it won't seal.

[jackssmirkingrevenge]

Diameter of the screw holding the rubber too big? Maybe it's hitting the seat. Love the 316 fittings btw, overkill FTW

[Matt_NZ]

Diameter of the screw holding the rubber too big? Maybe it's hitting the seat. Love the 316 fittings btw, overkill FTW

Yeah, they are beautiful fittings. (You wouldn't believe the price I got them for though *cough* staff price .)

Looking down barrel end it doesn't look like the screw is too big, any other ideas.

[Crna Legija]

maby the screw is lose and air gets under the rubber then out the hole where the screw is try to glue the hole or tighten the screw
if that dosent work try to dump air into it.

what pressure are you going to use? max out those ss fittings

[jackssmirkingrevenge]

As above, some araldite/JB weld between the screw/piston/face. At what pressure did you try it out?

[boyntonstu]

The threads are leaking.

Been there, done it.

BTW Not using a machine screw is dangerous.


I suggest that you drill out the piston from the rear to within about 3/8" from the face large enough for a screw driver, use a screw, nut, thread sealer, and Teflon tape.

I fixed a leak this morning using the thread sealing method above.

Holds air at 600 psi.

[FighterAce]

Hot glue piston at 600 psi?
I'd say thats more dangerous then not using machine screws and nuts above 150psi.

[Matt_NZ]

Trail was done at 100psi. You've got me convinced that air probably is getting around the screw. BTW Hot glue piston is only going to be temporary, til i find some nylon.

The threads are leaking.

I hope not I put a shit load of Teflon tape on those joints, guess I'll have to test in water.

what pressure are you going to use? max out those ss fittings

I would like to use up to 500-600, however i was told my quick connect fittings would only hold 250psi.

Edit:

BTW Not using a machine screw is dangerous.

Ok, I understand what you mean now. Will definitely use machine screws when i build a nylon piston. For now, Hot glue piston at lower psi.

[iknowmy3tables]

are you sure it's the piston, how did you secure that barb that your using as a seat, is it secured and airtight?

[Matt_NZ]

are you sure it's the piston, how did you secure that barb that your using as a seat, is it secured and airtight?

Barb is screwed in with some Teflon tape, then nipple is screwed hard against it. Are piston valves meant to be so frustrating.

[Gun Freak]

are you sure it's the piston, how did you secure that barb that your using as a seat, is it secured and airtight?

Barb is screwed in with some Teflon tape, then nipple is screwed hard against it. Are piston valves meant to be so frustrating.

Haha apparently they don't like me either

[jhalek90]

Just a small bit of help.

MY piston valve would not seal until i removed the screw holding the rubber gasket in place, and simply super glued the gasket on.

Its still on there, after 30-40 shots at 250-600 psi.

Ditch the screw, use some glue.

[boyntonstu]

Just a small bit of help.

MY piston valve would not seal until i removed the screw holding the rubber gasket in place, and simply super glued the gasket on.

Its still on there, after 30-40 shots at 250-600 psi.

Ditch the screw, use some glue.

What is the diameter of your piston and the shape of the gasket?

A photo would be appreciated.

[Crna Legija]

i would not take out the screw, the sealing face will blow out at 600

i don't think the hot glue will be brake at 600 coz my sealing face is some rubber it dosent get cut

[Matt_NZ]

i would not take out the screw, the sealing face will blow out at 600

i don't think the hot glue will be brake at 600 coz my sealing face is some rubber it dosent get cut

Ok, cheers. I've got a bit of fine tuning, then hopefully the piston will be sealing. Fingers crossed.