SpudFiles

Hey guys, I just recently built a small pneumatic spud gun, both the barrel and chamber are 18" long. I modded a sprinkler valve according to the 'official how to' posted on this site. I used the same base sprinkler valve as the one I use for my longer version that has an 45" chamber, a Orbit Watermaster 57101.

Anyway, the problem I'm having is that valve leaks out the front (where the barrel attaches) when I start filling it up. To fill it up I'm using a bike pump, but when I get everything straightened out I plan on using 12g CO2. I've been able to sucsesfully use my prior built valve on the 18" chamber and it works fine.
I'm pretty sure I've got everything in right because it's the same as my other valve which works.

Also, I've done some searching and it appears this is a common problem with modded sprinkler valves, but when somebody fixes theirs they simply put down that their valve is fixed and lack any explanation as to what was wrong.

So if any of you guys have any idea what is wrong, I could use the help.
Thanks.

Your post is very confusing, but I understand what you mean...

Did you try your other sprinkler valve on this gun?

That's irrelevent to your problem though...

Your valve isn't sealing right, you probably have some PVC shaving inside the valve that are keeping it from sealing... Take the valve apart and make sure there's nothing on the diaphragm or the green hole in the middle of the bottom of the valve... Make sure to clean both sides of the diaphragm... Then after cleaning put lithium grease lubricant on the bottom of the diaphragm where it seals with the green outlet\inlet...

check that the valve isn't backwards

Sorry about my confusing post, I've never done good in english class!
Everything is cleaned and lubed, no shaving or anything on the diaphram or elsewhere. And it isn't put on backwards. Obviously the diaphram isn't sealing, but I can't seem to find out why..

take it apart and pull out the small hite plastic thing on the side of the diaphram. then reassembal the valve. that helps it equilize faster

Did that, still has same problem.

Did you seal the hole that leads to the barrel from the pilot area?

I have had the same problem before,and i could fix it the only thing i could put it down to was a faulty sprinkler valve from the start so just get another one or if u find the fix i would like that due to the reason that i will have an extra sprinkler valve.

I wonder if you could fill it faster it wouldn't leak. Like maybe the pump isn't able to create enough pressure fast enough to make the valve seal. I would suggest filling it at a gas station since that pump should be faster than a bike pump. Or a regular home air compressor should work.
It sounds like you may also have another valve, maybe try switching that one out to see if it is in fact just the vavle.

My valve leaks too , same type

lol your problem is that you flipped the little manual lever by the solinoid up

If I have a leaky valve I just put some grease or heavy oil (white lithium or chain lube) on the diaphragm, it helps the valve seal.