Any suggestions?

[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!

[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.

[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?

[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.

[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.

[andrew67]

That was great help thanks heaps!!!!!

[jackssmirkingrevenge]

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?

[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!

[jackssmirkingrevenge]

All you need to know is here: http://www.spudfiles.com/how-to-databas ... 23626.html

[andrew67]

Thank you!as I said your help is always usefull.ill return the help if I ever can!well done

[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?

[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.

[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!

[jackssmirkingrevenge]

I don't want to use e-bay

Why not? It,s the cheapest and easiest option

[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.