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Any suggestions?

Posted: Fri Nov 01, 2013 11:21 am
by andrew67
This worked fine until the gun started firing as I pressure it,at first I thought it may be a leak but lengthened the piston travel slightly with no success,the casting resin has a crack in it,I'm thinking it may be leaking from there?any one have a suggestion?it won't hold pressure to test in water either!

Re: Any suggestions?

Posted: Fri Nov 01, 2013 11:23 am
by mako
There really isn't enough detail to even make a guess. Even if it won't hold pressure, you should be able to put it in the water and then pump air into it. Assuming there isn't any filling leakage, you should be able to find the source of the problem, or at least get an idea.

Re: Any suggestions?

Posted: Fri Nov 01, 2013 1:10 pm
by andrew67
Maybe!but the piston fires once it has the slightest pressure I'll try anyway,my next question is can a tank be added to these to get multi shots?if so do you have or know a link with good detail?

Re: Any suggestions?

Posted: Fri Nov 01, 2013 1:21 pm
by mako
The problem remains. We can't see anything, so it's hard to determine what you have there. Without more knowledge, nobody could recommend anything.

Re: Any suggestions?

Posted: Fri Nov 01, 2013 4:19 pm
by andrew67
It is about 180*14mm brass tube 15mm piston with 10mm travel and a 6mm barrel it uses a shrader valve to connect the bicycle pump and a blow gun as the release valve all the joins for the blow gun and pump connections have had casting resin moulded around them to prevent possible leaks from any hoses or joins.another pic that maybe a bit clearer but it won't get much better than that.thanks for any help you may be able to give.

Re: Any suggestions?

Posted: Sat Nov 02, 2013 9:42 am
by andrew67
That was great help thanks heaps!!!!!

Re: Any suggestions?

Posted: Sat Nov 02, 2013 10:12 am
by jackssmirkingrevenge
Image

If the pilot area is leaking, that's a cause for premature firing ;)

If its not holding pressure, have you tried pressurising the chamber while under water, dipping it in a bath for example, to see where the specific leaks are?

Re: Any suggestions?

Posted: Sat Nov 02, 2013 10:40 am
by andrew67
Thanks jackssmirkingrevenge,your help is always usefull,yep I've done as you mentioned,I found the leak at the end of the pump then casted fiberglass resin on top of the casting resin to seal the leak (fiberglass resin is crap)I bought it by accident,it cracked,it seems to be more sensitive than casting resin when it comes to mixing ratios.ive re-done the cast and I'll see how it goes but now it seems I've learnt how these piston valves work so I should be able to build something more bullet proof, looking for something with multi shot piston valve,do you have a link that may help me? I've just started looking around here but can't seem to find much that has a lot of detail?thanks heaps! If you can't help no stress I'll keep looking!

Re: Any suggestions?

Posted: Sat Nov 02, 2013 10:42 am
by jackssmirkingrevenge

Re: Any suggestions?

Posted: Sat Nov 02, 2013 10:48 am
by andrew67
Thank you!as I said your help is always usefull.ill return the help if I ever can!well done

Re: Any suggestions?

Posted: Sat Nov 02, 2013 11:31 am
by andrew67
Do you know who sells QEV? Plumbers supplies,local hardware?been searching but I don't want to use e-bay.etc if I don't have to,or modify a sprinkler valve,would a plumbing supplies sell them?

Re: Any suggestions?

Posted: Sat Nov 02, 2013 11:38 am
by mako
Best place to look is Ebay. I seriously doubt you'll be able to find them at a generic store. If you don't want to use Ebay, you may be out of luck, unless you live somewhere you can find a paintball gun shop. Some paintball markers use QEV's, so you may be able to find one that way.

Re: Any suggestions?

Posted: Sat Nov 02, 2013 11:48 am
by andrew67
Ok,thanks I'm in aus so paintball shops are as good as non existent here,I was hoping some sort of industrial supplies shop may sell them and I could buy over the counter but looks like E-bay.thanks for helping!

Re: Any suggestions?

Posted: Sat Nov 02, 2013 11:48 am
by jackssmirkingrevenge
andrew67 wrote:I don't want to use e-bay
Why not? It,s the cheapest and easiest option ;)

Re: Any suggestions?

Posted: Sat Nov 02, 2013 11:54 am
by mako
Yeah, in that case you're in trouble. I can't think of any application for a QEV of the ratings you'll need other than paintball. Most other QEV's are huge, bulky, high flow, high pressure industrial components.
JSR, correct me if I'm wrong there?

I think that you're only other option, if you won't use EBAY, is to build one yourself.