Valve Sealing Problem
Need a little help/advise. So I took my Selph valve and decided to make a larger one piece stem. Bored out the body to .3125″ and made a nice one piece stem at .309″. Put a .250″ hole in it which you can slide the condor stem in it until it hits the tophat. Everything was good until I put it in a tank and tried to fill it. Valve leaks and emptys tank out in less then a minuite. No mater how I made the stem seal it leaked the same. You can grab the tophat and change the leak but when you let go it is still leaking the same. I compared it to my Blod valve and the tophat on it you can wiggle a little also. Only thing I can think is I need to make the stem OD a little larger, say .311″. I make the stem seals out of acetal and even tried derlrin just to see if it would work because it is softer. Made sure the back of valve is good by facing it of and scotch brighting it so it is perfect and nice and smooth. I’m kinda puzzled. I have made new stem seals for my blod valve a couple of times with no problems. Anybody have any ideas before I waste another 4 hours trying to get it to work. Thanks
All Replies
Ok made a new stem seal and used the new body and it seals fine. Only problem is it needs more hammer and spring. I filled to 3000 and it won’t open the valve all the way. Shot until it peaked at 860 fps with 6 rings and next shot was 853 fps. Checked the tank pressure and it was at 2270 psi. So I’m saying 860 fps with 2300 psi. Now I need to up the spring and see what it can do on 3000 psi. I still can’t figure out why it takes so much spring to open the valve. Valve seal is .010″ bigger around then a condor seal. Anybody know?
Not really worth making them. It takes to much time to make them on manual lathe. They need to be made on CNC.
you ever plan on selling those? i’d be interested in one.
1144 steel.
doug, i like the valve body, what is it turned from?
Here’s the hole under the burst disc and new valve body I made for it.
Glad to hear you figured it out 😀
Turns out when I bored the body out I got into the burst disc hole. That is why no mater what I did it still leaked the same. I JB welded and put a plug in it but haven’t made a new seal and re surfaced the end to go back to the way it should have worked. I also made a new valve body but need to cut the o ring grove in the body so it seals when fired.
*edit* didn’t read properly, disregard if you read the original message.
It kind of sounds like the sealing face of your valve itself (the metal part) is leaking.. does the old valve stem still seal up properly?
Yep. I spent at least 4 hours making different shapes and sizes and I’m still right where I was when I started. I even made a coned one. I think I will order up 2′ of your material. What do I have to loose. Need to work on my compressor so I can fill my tanks first.
I take it, it still leaked… 😕 😯
That’s what I thought after a while so I made one that didnt go all the way through. I did that so I could adjust it but ended up cutting it of and just putting it on the end.
I have no idea. Probably Delrin/Acetal. Acetal is the chemical name for Delrin… 😉
Are you sure it isn’t leaking at the hole that is drilled straight through? I know the hi-flo valve hole is not all the way through on the delrin stop…
What is the original seal made out of? Tim told me awhile ago that asetal is the best to use. Not sure if the way the valve works it is best for this valve though.
- You must be logged in to reply to this topic.
well, i looked into poppet valve design earlier, and the best that i can ascertain is that the orifice size dictates the amount of force needed to open the valve for a given pressure, omitting the valve spring as a factor.
orifice i believe meaning the area separating the pressure side from the atmosphere, this would be the hole on the underside of the brass face in the standard AF valve configuration.
if this is the case, there is a tradeoff. better flow to the stem between seal and brass with a large orifice, or easier opening with a smaller orifice. if this is the case, the best option for a valve that doesnt require sear-wrecking spring or heavy recoiling hammer, means optimizing air flow to be as laminar as possible. i am starting to become wary of putting too much tension on the sear, as i had to COMPLETELY strip my gun yesterday, and i dont like how these trigger components have little gaps in parts of the bars, and the steel is a bit softer than you may think. so tread with caution. we are in desperate need of someone with the means to manufacture an aftermarket trigger group of a better steel, or perhaps a different metal altogether(im thinking titanium…)
hope this helps, as your new valve build inspired my few hours of research. 😎