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Well I built my first cannon powered by a sprinkler valve a couple of weeks ago and I modifyed the sprinkler valve. The first time I charged it up there was a very small leak coming out of the sprinkler valve and through the barrel I took no notice of it but it has just been getting worse and worse to the point if you charge it up and leave it for 5 sec the potato slug will pop out of the barrel because of the pressure build up behind it.I now there is a sprinkler valve trouble shooting thing and I tryed all the things they said to do on there and it didnt help. I relize it probably is defective. But I would like to know if there is any thing else I can try because it would be very annoying to have to go get another one.

Where you looking at the Wiki? Or a different guide?

Theres a logical and an illogical reason that your valve is leaking. The logical would be that you didn't tap the top threads properly and air is leaking out the top, thus piloting the valve very slowly.
The illogical would be that the Yeti and Nessy invaded your house and tampered with your cannon, hoping to put you out of commission long enough for Hillary (alien queen) to win the 2008 election. Little did they know, that you probably don't vote anyway.
You pick the one that sounds the best

jrrdw wrote:Where you looking at the Wiki? Or a different guide?

I was looking at the sticky in the pnematic cannon discusion called sprinkler valve troubleshooting. And I know the top threads are air tight beacause I sprayed soapy water on them to check and it didnt bubble

OK, this has happened to me to, and its an easy fix. Your diaphragm might be dirty. Just open up the valve, yank out the rubber diaphragm, and check for crap on the rubber ring that seals the barrel port. Clean it off relay well and reassemble the valve.

That was on that sprinkler valve troubleshooting thing that I was referencing to earlyer so I ve already tryed that

Witch guide did you do? Have you checked that your barrel port and sealing face are completely smooth? Do you still have the solenoid in? It might be loose in its threads. What does your pilot assembly look like?

My solinoid I will go tighten it with a wrench and test it right now and my pilot asemplely is just a blowgun attached to the sprinkler.And the guide I used is a sticky in the pnuematic cannon discusion on this website. And my barrel port and sealing face seem to be smooth. I mean I m just thinking more and more that its defective.


Edit: The solinoid valve didnt help at all

There really isn't a lot of things to go wrong on a sprinkler valve. did you use teflon tape on your pilot assembly? Maybe if you could snap a pic of the valve?have you done any modification to the blowgun valve? Is the valve top tightened down tight all around? btw, what are you filling the thing with?

Try the spudwiki for optional things that arn't said where you looked. There is a wiki button at the top of this page.

Do you have pics of your cannon and vavle set up anywhere here? If not can you post some of your valve, piston and such?

no I did not use teflon tape on the pilot assembley Ill go put some on right now Im filling the gun with a bike pump( I know lame) but I am curently saving up for an air compresser.I have not made any modification to the blowgun. I would take a pic but I have no acsess to a digital camera (I hope I get one for chrismas ).And yes the valve top is very tight all the way around.

^^^ I think that may be your answer. You might have itty bitty leeks in the threads on your blowgun and valve top. I have found that the saopy water method isn't always accurate. dunk the thing in a tub of wather and look for leaks around the valve. I hope this helps.

mopherman wrote:^^^ I think that may be your answer. You might have itty bitty leeks in the threads on your blowgun and valve top. I have found that the saopy water method isn't always accurate. dunk the thing in a tub of wather and look for leaks around the valve. I hope this helps.

That will find any leaks allrite.

Okay Ill do that

Edit:I have just put the whole thing underwater while pressurised and the only bubles I saw were coming out of the barrel