400psi piston vavle

[POLAND_SPUD]

ok now I finally got my own QEV.... I've opened it and it seems that there is enough space there to build custom piston.... but first I would use it as it is without modyfying..... at least for sometime...

[ALIHISGREAT]

looks good, but what are you going to do with a pilot volume so massive you could fit a medium sized pink elephant into it?

yes but i will also make a the piston long and move the barrel further into the tee to ruduce the length of the piston and i will pilot wil either a qev or a 22mm piston would a qev be alright at 400psi?

[jackssmirkingrevenge]

The body can probably take it, but I can't tell how the piston would stand up to repeated abuse at that pressure.

[ALIHISGREAT]

The body can probably take it, but I can't tell how the piston would stand up to repeated abuse at that pressure.

well we crazy fools from the uk use them at 300psi (twice the recommended pressure) with no problem but i'm a bit nervous of using one at 400psi, maybe i'll let rag do it first or maybe i will just make a second 22mm piston with a 15mm porting and hope i can get both to work. two pistons would be quite cool 8) , has anyone done it before, i have see pistons piloted by qevs but no piston-on-piston action

[jackssmirkingrevenge]

You'd still have to pilot the second piston, this could go on forever

There isn't a huge stress difference between 300 and 400 psi, it could probably take it.

[MaxuS]

I think you'd be be going so overkill if you were piloting a 28mm piston with a 15mm one. Go QEV with custom bit.

[al-xg]

I can't see why a piston QEV would need to be modified for 400psi, the piston on my 3/4" is at least 6mm thick and thicker on the sealing face.
I've only used mine to 320psi 'caus my only pressure source is a track pump I tweaked.
I really can't see where it would fail.

[Infernal Maveric]

QEV's are fina at 400 PSI. They have no real "failing-point" or weak spot where it would blow up. I have, and will continue to use QEVs at 400PSI.

[ALIHISGREAT]

ok thanks for the info... 1/2" qev it is then

edit: would this poppet valve rated to 10bar be allright for a pilot? i know blowguns can take way more than their rating http://www.airlines-pneumatics.co.uk/we ... =s07010750

[MaxuS]

Should be fine yeah, it's 3/8" so it will have more flow than a regular blowgun. To make it work efficiently though, you'll have to pull the lever fairly fast because it says:

The outlet flow can be regulated by varying the pressure on the hand lever.

[ALIHISGREAT]

you'll have to pull the lever fairly fast

yeah i hope its no harder to open than a blowgun and if it is i will mod the lever to make it longer

hmm i was gonna ask something else... ahh yes do you guys think i should make a camlock breach loader? or might it constrict the flow? another option is to mod a ball valve as i will probably shoot marbles the most any other ideas?

[POLAND_SPUD]

ALI please post a message here if it works fine at 400 psi.... the only question is..... how much more it can take ?

[ALIHISGREAT]

woah i was just figuring out how much this beast will cost and the poppet valve is as good as £30 looks like a sleeve valve (yes i may have got the idea from HEAL) or a ball valve for me

[POLAND_SPUD]

lol I would say that the sleeve valve is even better as a pilot valve than the poppet valve... so what's the problem ?

[ALIHISGREAT]

lol I would say that the sleeve valve is even better as a pilot valve than the poppet valve... so what's the problem ?

well the poppet would be an ideal trigger without modding, to make the sleeve valve into a good trigger i will ahve to attach a trigger to it