Trigger mech for a hammer valve?

Show us your pneumatic spud gun! Discuss pneumatic (compressed gas) powered potato guns and related accessories. Valve types, actuation, pipe, materials, fittings, compressors, safety, gas choices, and more.
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jackssmirkingrevenge
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Mon Oct 30, 2017 5:24 am

If your valve piston is sealed it should suffice.

If not, you can use it to pilot a small QEV which then pilots your main valve, something like this costs next to nothing and will have no problem taking 40 bar.

Zeus recently took one to more than twice that pressure without failure.
hectmarr wrote:You have to make many weapons, because this field is long and short life
Alex345
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Mon Oct 30, 2017 4:39 pm

Sweet! Just ordered both the QEV and the solenoid valve :) Hope they arrive soon! Just need to find a 24vdc power supply...
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jackssmirkingrevenge
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Tue Oct 31, 2017 8:02 am

Good luck with it, looking forward to seeing some high pressure destruction ;)
hectmarr wrote:You have to make many weapons, because this field is long and short life
Gnarp
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Wed Nov 01, 2017 7:13 am

Alex345 wrote:Sweet! Just ordered both the QEV and the solenoid valve :) Hope they arrive soon! Just need to find a 24vdc power supply...
You could use a dc step up converter from 12v etc.

https://m.ebay.com/itm/DC-DC-Adjustable ... nav=SEARCH

I use one to boost 2pcs 12v solenoid to 20v:p it works good.
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Wed Nov 01, 2017 7:36 pm

Gnarp wrote:
Alex345 wrote:Sweet! Just ordered both the QEV and the solenoid valve :) Hope they arrive soon! Just need to find a 24vdc power supply...
You could use a dc step up converter from 12v etc.

https://m.ebay.com/itm/DC-DC-Adjustable ... nav=SEARCH

I use one to boost 2pcs 12v solenoid to 20v:p it works good.
Well turns out it's 24v AC instead of DC. Got the valve in the mail today, says it's a 24vac model drawing 19 watts. I just ordered a 230 to 24vAC converter providing 25 watts so i hope i'm good. I'm a huge noob with electrics :p

I reckon that the QEV will take a bit longer to get here as it's from China
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Zeus
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Wed Nov 01, 2017 11:11 pm

Well I have to chime in here, can't be having you dragging an extension lead around to plink.

You don't need AC to run one of those solenoids. 24VDC is perfectly acceptable. But easier yet, just use three 9 volt batteries connected positive to negative, in series. That'll obviously give you 27 volts, given the short duty cycle (the amount of time it's turned on) it won't overheat and the batteries will last for ages.
/sarcasm, /hyperbole
Alex345
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Thu Nov 02, 2017 4:16 am

Zeus wrote:Well I have to chime in here, can't be having you dragging an extension lead around to plink.

You don't need AC to run one of those solenoids. 24VDC is perfectly acceptable. But easier yet, just use three 9 volt batteries connected positive to negative, in series. That'll obviously give you 27 volts, given the short duty cycle (the amount of time it's turned on) it won't overheat and the batteries will last for ages.
Thanks! I think the power supply i ordered will be nice for most static testing indoors or when shooting from indoors to outdoors from a fixed position. The 3x 9v battery pack would be great for some on the go plinking :D Because yeah i was wondering on what to do with the cannon being attached to a wall socket when i want to shoot it outside but this would solve that nicely :)
Alex345
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Sat Dec 09, 2017 5:17 am

Not leaving you guys hanging here but the QEV arrived only yesterday after me posting that i ordered it... Took over a month to get here god, if some of those China sellers would just offer a slightly faster shipping service for like 10$ instead of the free one taking over a month i'd be all over it.

But it's here! The solenoid valve came from Holland so that was here like 2 days after buying it but as i feared it opens the valve waaay to slow, opening a 1/2" valve with a 1mm pilot opening already sounded a bit weird to me :p

I'll slap on the QEV as soon as time allows me, and i'll keep you guys posted :)
Air2theBrain
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Sat Dec 09, 2017 3:03 pm

Damn thats a long time for a qev to arrive...looking forward to your build. :)
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Anatine Duo
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Sat Dec 09, 2017 7:22 pm

Sometimes long slow shipping is better... fast shipping to Canada usually involves a courier who will happily charge me C.O.D. to tell me that the item is duty free :(
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Sat Dec 16, 2017 3:07 pm

Yeah i have another package from the US that is currently held by customs...

First few test shots were promising. It actually made a bang instead of a whoosh with the QEV, yet the large clumsy 2" pipe parts that make up the camber are leaky as hell no matter how much i wrap them with gas grade teflon tape, the fridge comp can't keep up with the leaks anymore when the pressure reaches around 30 bar. And i just hate the flax and paste option...

Would PTFE paste work better for this? The leak is mainly in the 2" end cap of the camber and is very focused in specific spot, so i'm actually think that the cap itself might have some kind of defect...

Any better alternatives to solve these leaks? Does PTFE paste actually work better?
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farcticox1
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Sat Dec 16, 2017 5:33 pm

I normally use this on all my joints, it fills gaps well.
PD250BT.jpg
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Or this is a bit thicker, but messy
CP250BT.jpg
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jackssmirkingrevenge
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Sun Dec 17, 2017 6:11 am

Alex345 wrote:Any better alternatives to solve these leaks? Does PTFE paste actually work better?
15 minute epoxy like Araldite or JB Weld works for me if you want a semi-permanent joint.
hectmarr wrote:You have to make many weapons, because this field is long and short life
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Wed Dec 27, 2017 12:38 pm

Ok i went to some basic DIY stores but hey did not not stock any decent epoxy except the ones from Bison so i went to a more specialized store and found that they actually had some professional pipe sealant that goes up to 2" fittings so i got that, it's curing now :)

I'ts a busy period for everyone now so i'll post back when i make some more progress ;)
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Sat Jan 13, 2018 10:30 am

Update: Fix one leak = find three smaller ones... I'm gonna have to take the entire valve apart and and use the sealant on the actual valve stem and a screw that i used to seal off a wrongly drilled hole i once made.

Also, filling the chamber is a true pain because i use 3/8 union fittings to attach the fridge comp to the chamber and pilot. Problem is that i use 6mm id malleable copper pipe to go from the comp to the chamber and pilot, so moving the cannon can untighten some fittings and cause them to leak. So i'm also going to build a filling station with an actual cradle for the cannon to rest on and use two pressure lines so i can fill both the chamber and pilot at the same time.

And before i can do any of that i'm gonna need to clean up my workspace first :p
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