Login    Register
User Information
Username:
Password:
We are a free and open
community, all are welcome.
Click here to Register
Sponsored
Who is online

In total there are 70 users online :: 5 registered, 0 hidden and 65 guests


Most users ever online was 218 on Wed Dec 07, 2016 6:58 pm

Registered users: Bing [Bot], Exabot [Bot], Google [Bot], Google Adsense [Bot], Yahoo [Bot] based on users active over the past 5 minutes

The Team
Administrators
Global Moderators
global_moderators.png CS

QEV and shock pump questions

Post questions and info about pneumatic (compressed gas) powered cannons here. This includes discussion about valves, pipe types, compressors, alternate gas setups, and anything else relevant.
Sponsored 
  • Author
    Message

QEV and shock pump questions

Unread postAuthor: SP00K » Sat Jul 31, 2010 12:45 pm

I plan on making a coaxial pistol. I want to make a qev like this one: [youtube]http://www.youtube.com/watch?v=b4ZgXqiaySc&translated=1[/youtube] but I do not fully understand how it works. I thought about using a modded sprinkler valve but it seems just too clunky for a pistol. I also considered just using a blowgun (which is probably what I'll end up doing). I am going to use 1" pipe for the chamber with a .25" diameter barrel.

That's where the shock pump question comes in. I wanted to mount the shock pump on the bottom of the underside of the gun. But I recently read a thread where someone's shock pump exploded when filling a chamber over 60cc in size. Could someone fill me in on shock pumps a bit?
  • 0

We are all worms, but I do believe I am a glow worm.

~Winston Churchill~
User avatar
SP00K
2nd Lieutenant
2nd Lieutenant
 
Posts: 212
Joined: Wed Dec 03, 2008 4:20 pm
Location: Ohiya
Reputation: 0

Unread postAuthor: jackssmirkingrevenge » Sat Jul 31, 2010 1:03 pm

Have a look at this project as an example of using the a blowgun as both valve and chamber.

Referring to this exploding shock pump story, I would say it was an isolated incident and really a 60mL chamber is a little too much for a shock pump, I usually use mine for less than one fourth of that - even if the pump doesn't explode, your arm will fall off from the effort.
  • 0

User avatar
jackssmirkingrevenge
Donating Member
Donating Member
 
Posts: 24225
Joined: Thu Mar 15, 2007 11:28 pm
Country: Holy See (Vatican City State) (va)
Reputation: 66

Unread postAuthor: POLAND_SPUD » Sat Jul 31, 2010 1:03 pm

it's a piston valve
  • 0

Children are the future

unless we stop them now
User avatar
POLAND_SPUD
Chief of Staff
Chief of Staff
 
Posts: 5405
Joined: Sat Oct 13, 2007 4:43 pm
Country: Israel (il)
Reputation: 10

Unread postAuthor: FighterAce » Sat Jul 31, 2010 1:26 pm

jackssmirkingrevenge wrote:a 60mL chamber is a little too much for a shock pump, I usually use mine for less than one fourth of that - even if the pump doesn't explode, your arm will fall off from the effort.


Yep, I totally agree with that now... that shock pump just wasnt built for the kind of use it got :D I'm definitely overbuilding my new pump so most of the components can handle more then triple the pressure I intend to use.
The pump in the incident was not overbuilt at all... it was made for 400 psi max and I took it to the limit every time I used it, thats it.

If you go with something less then 15cc, like JSR said, I think that shock pump would do just fine.

btw. it took me about 150 strokes with that pump to reach 400 psi... my arm didnt fell off but after a few refills it did :D And dont think I was using all that volume for just one shot, it was a crude ball valve multi shot but it worked... got about 7 shots per fill.
  • 0

User avatar
FighterAce
1st Lieutenant
1st Lieutenant
 
Posts: 286
Joined: Fri Oct 23, 2009 1:28 pm
Location: Croatia/Zagreb
Country: Croatia (hr)
Reputation: 1

Unread postAuthor: Lockednloaded » Sat Jul 31, 2010 2:08 pm

for a pistol, I think you should go with a .25 barrel and a .5 chambered co-axial, I recently built a pistol with a .5" x 12" chamber and 5/16" x 12" barrel. It is a co-axial configuration it take 20 pumps to reach 150 psi and is piloted by a blow-gun
  • 0

I love lamp
User avatar
Lockednloaded
Major General
Major General
 
Posts: 1558
Joined: Thu Sep 03, 2009 9:38 pm
Location: Texas, USA
Reputation: 0

Unread postAuthor: Stolly32123 » Sat Jul 31, 2010 9:45 pm

if only the video was in english :-(
  • 0

User avatar
Stolly32123
Specialist
Specialist
 
Posts: 50
Joined: Sun Jul 04, 2010 7:50 am
Location: Australia
Reputation: 0

Unread postAuthor: jackssmirkingrevenge » Sat Jul 31, 2010 10:29 pm

Stolly32123 wrote:if only the video was in english :-(


Surely it's fairly easy to understand even without sound.
  • 0

User avatar
jackssmirkingrevenge
Donating Member
Donating Member
 
Posts: 24225
Joined: Thu Mar 15, 2007 11:28 pm
Country: Holy See (Vatican City State) (va)
Reputation: 66

Sponsored

Sponsor
 


Unread postAuthor: lemming124 » Sun Aug 01, 2010 2:08 am

piston valve
spring resets the piston and acts as a bumper, there are also quite a few o rings, to reduce pilot volume I think.
  • 0


lemming124
Specialist
Specialist
 
Posts: 51
Joined: Sun Oct 18, 2009 6:18 am
Reputation: 0

Unread postAuthor: wyz2285 » Sun Aug 01, 2010 9:50 am

the video is a self close piston valve,i have watched it a lots of times :)
  • 0

User avatar
wyz2285
Major General
Major General
 
Posts: 2244
Joined: Sat Mar 06, 2010 7:50 am
Location: Porto, Portugal
Country: Portugal (pt)
Reputation: 12

Return to Pneumatic Cannon Discussion

Who is online

Registered users: Bing [Bot], Exabot [Bot], Google [Bot], Google Adsense [Bot], Yahoo [Bot]

Reputation System ©'