Pengun 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.
User avatar
finland66
Private 3
Private 3
Posts: 54
Joined: Fri Jan 04, 2013 1:30 pm
Location: Finland

Mon Sep 09, 2013 9:06 am

Hello

I am making pengun for something like 60 bar mayby unreg co2. But shrader valve won't work becose its hard to push open. Have anybody any ideas for the valve.
_____________________________
"A person who never made a mistake never tried anything new"
- Albert Einstein
User avatar
jackssmirkingrevenge
Five Star General
Five Star General
Posts: 26216
Joined: Thu Mar 15, 2007 11:28 pm
Has thanked: 576 times
Been thanked: 347 times

Donating Members

Mon Sep 09, 2013 9:30 am

Here's one idea I had:

Image

From this thread.
hectmarr wrote:You have to make many weapons, because this field is long and short life
User avatar
Technician1002
Captain
Captain
Posts: 5189
Joined: Sat Apr 04, 2009 11:10 am

Mon Sep 09, 2013 9:46 am

That design will need a stop to prevent the piston valve from ejecting. How is it fired?

A slight modification attaching the piston to the "pen button" so pulling the button also pulls the piston would work. A re-coloring of the button to match the piston color could represent them moving as a unit. A slight modification to make the piston able to move on the trigger and it would become a QDV.

The aprox 30 psi per pump stroke is not linear. It will roll off to a max pressure of the compression ratio of the pump. Compression ratio = pump volume / dead volume. In other words when all the air from the pump stroke volume is able to fit compressed into the dead spaces by the o rings, around the pump, in the check valve tube, and stops going through the check valve due to equal pressures.
User avatar
finland66
Private 3
Private 3
Posts: 54
Joined: Fri Jan 04, 2013 1:30 pm
Location: Finland

Mon Sep 09, 2013 10:05 am

Thanks

Jsr is your desing triggeret by pulling that "pen button." Mayby i also cant put one of these http://www.valve-push-button.com/ but are they hard to push at high pressures?
_____________________________
"A person who never made a mistake never tried anything new"
- Albert Einstein
User avatar
jackssmirkingrevenge
Five Star General
Five Star General
Posts: 26216
Joined: Thu Mar 15, 2007 11:28 pm
Has thanked: 576 times
Been thanked: 347 times

Donating Members

Mon Sep 09, 2013 12:41 pm

Technician1002 wrote:A slight modification attaching the piston to the "pen button" so pulling the button also pulls the piston would work.
Look closely, the button is threaded to the piston, the idea is that you pull it to fire - it is a QDV :)
The aprox 30 psi per pump stroke is not linear.
Hence my "very roughly" notation ;)
Mayby i also cant put one of these http://www.valve-push-button.com/ but are they hard to push at high pressures?
Hmmm... let's look at this: http://valve-push-button.com/magento/pu ... tball.html

Rated for 54 bar.
Button force to open valve at 800 psi pressure drop = 30lbs.
By comparison, typical trigger pull for a firearm is around 5lbs....
hectmarr wrote:You have to make many weapons, because this field is long and short life
User avatar
finland66
Private 3
Private 3
Posts: 54
Joined: Fri Jan 04, 2013 1:30 pm
Location: Finland

Mon Sep 09, 2013 1:12 pm

Damn I'l need body trainer to shoot my gun :lol:
Any other ideas wich allows filling from schrader.

Edit: schrader where I gone fill the gun wont have core if not needed
_____________________________
"A person who never made a mistake never tried anything new"
- Albert Einstein
User avatar
jackssmirkingrevenge
Five Star General
Five Star General
Posts: 26216
Joined: Thu Mar 15, 2007 11:28 pm
Has thanked: 576 times
Been thanked: 347 times

Donating Members

Mon Sep 09, 2013 1:25 pm

finland66 wrote:Damn I'l need body trainer to shoot my gun :lol:
Any other ideas wich allows filling from schrader.
Here you go, this time colour coded for clarity :)
Attachments
qdvpengun.PNG
qdvpengun.PNG (3.71 KiB) Viewed 2657 times
hectmarr wrote:You have to make many weapons, because this field is long and short life
User avatar
finland66
Private 3
Private 3
Posts: 54
Joined: Fri Jan 04, 2013 1:30 pm
Location: Finland

Mon Sep 09, 2013 1:40 pm

Thanks a lot good idea I'l just make chamber bigger. By the way i think that this could work too
Attachments
Valve idea
Valve idea
_____________________________
"A person who never made a mistake never tried anything new"
- Albert Einstein
User avatar
jackssmirkingrevenge
Five Star General
Five Star General
Posts: 26216
Joined: Thu Mar 15, 2007 11:28 pm
Has thanked: 576 times
Been thanked: 347 times

Donating Members

Mon Sep 09, 2013 2:37 pm

the piston needs to be balanced though

http://www.spudfiles.com/forums/quick-d ... 17858.html
hectmarr wrote:You have to make many weapons, because this field is long and short life
User avatar
finland66
Private 3
Private 3
Posts: 54
Joined: Fri Jan 04, 2013 1:30 pm
Location: Finland

Mon Sep 09, 2013 11:21 pm

Okey many thanks lots of usefulli info. I'l start to do something :)
_____________________________
"A person who never made a mistake never tried anything new"
- Albert Einstein
Post Reply