Trouble with my piston valve

[Northir]

as some of you know im working on my first piston valve, using MrCrowlys instructiable i have it built, and when i pressureize it it seals my seat, when i release the pilot it all comes out with out releasing the piston thoughts ideas?picture comming

[potatoflinger]

Most likely the gap between your piston and the valve housing is too big. The solution would be to make your piston fit tighter in your valve housing or get a bigger pilot valve.

[Technician1002]

Often overlooked in PVC is under pressure the pipe has some flex and give. What fit before will change as the pressure is applied. You may want an o ring to fill the enlarging gap. My Mouse Musket exhibited this. Worked fine at lower pressure and sometimes just hissssed and no boom at higher pressure. A little heavier grease fixed it most of the time.

[cannon monkey]

try o ring or duck tap for now make the fit alot tighter
if that dont work try bigger pilot valve
good luck

[MrCrowley]

try o ring or duck tap for now make the fit alot tighter
if that dont work try bigger pilot valve
good luck

He's got a 1" sprinkler valve on there by the looks. If that doesn't do it, the piston is at fault.

Edit:
When are you going to trim your sealing face to the same diameter as the piston?

[Northir]

>.< lol when i get better at it, that piece of rubber was to thin using something with a little more depth

[MrCrowley]

Try using superglue to glue it down to the piston

[Northir]

super glued now, just did a dry fire @ 50 PSI and she works, was loud and wonderful. . . but i now i have a barrel leak, my piston is 2" and my seat OD is 1.9 thoughts? also im using a piece of rubber from an old water tank bladder instead of a bike inner tube, my seat is square i know it is since i used a compound miter saw to cut it, then lightly sanded it with 200 grit sand papper

[MrCrowley]

$10 says it's leaking out of the bolt and washer on the front of the piston. Epoxy that up, make sure not to get any on the rubber sealing face that would be in contact with your barrel/seat.

[Northir]

would shoe glue work?

[inonickname]

Shoe/goop? If it's the stuff I'm thinking of, most likely.

[Northir]

muhahahaha! it lives! onbly leaks left are in my fittings, and i think im out of Teflon tape

[FORE!!!!]

muhahahaha! it lives! onbly leaks left are in my fittings, and i think im out of Teflon tape

lol i think we have all been there!!!

[Northir]

thank you MrCrowly for sharing this amazing cannon with every one, now i believe i have a better understanding of the piston valve and can make my own cannons, of course im broke now lol but thats ok

[cannon monkey]

i think 65% of the people on this website are broke and if not they are at lowe's lol