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 55 users online :: 5 registered, 0 hidden and 50 guests


Most users ever online was 155 on Mon Aug 15, 2016 1:40 am

Registered users: Bing [Bot], Google [Bot], mrfoo, MSNbot Media, Yahoo [Bot] based on users active over the past 5 minutes

The Team
Administrators
Global Moderators
global_moderators.png CS

PCP building blog

Built a pneumatic cannon? Then post it here! This section is for completed, finished cannons that you have built. Please include pictures and information.
Sponsored 
  • Author
    Message

Unread postAuthor: Gun Freak » Sat Feb 25, 2012 5:48 pm

Alright thanks for the advice :) I'll try a 60 psi feed for filling up my scuba tank :D
  • 0

OG Anti-Hybrid
One man's trash is a true Spudder's treasure!
Golf Ball Cannon "Superna"M16 BBMGPengunHammer Valve Airsoft SniperHigh Pressure .22 Coax
Holy Shat!
User avatar
Gun Freak
Lieutenant General
Lieutenant General
 
Posts: 4969
Joined: Mon Jan 25, 2010 4:38 pm
Location: Florida
Country: United States (us)
Reputation: 11

Unread postAuthor: wyz2285 » Sun Feb 26, 2012 3:21 pm

Just finished the hammer and trigger :)
Here are some photos of the trigger
(Have next month full of tests and exams, so I won´t be able to do more progress until april :( )
  • 0

Attachments
IMG148.jpg
IMG150.jpg
CpTn_lAw wrote::D "yay, me wanna make big multishot pnoob with 1000 psi foot pump compressor using diamond as main material. Do you think wet bread make good sealant? " :D
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

Unread postAuthor: Cosmic Muffin » Tue Feb 28, 2012 7:20 am

What have you made the trigger and sear from?
  • 0

User avatar
Cosmic Muffin
1st Lieutenant
1st Lieutenant
 
Posts: 275
Joined: Mon Jan 14, 2008 10:30 pm
Location: arse end of nowhere
Reputation: 0

Unread postAuthor: jackssmirkingrevenge » Tue Feb 28, 2012 7:25 am

Cosmic Muffin wrote:What have you made the trigger and sear from?


Judging by the colour and consistency, this is my theory:

[youtube]http://www.youtube.com/watch?v=-M43NjbTe5I[/youtube]
  • 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: wyz2285 » Tue Feb 28, 2012 7:41 am

nylon. They are strong enough and easy to work with.
  • 0

CpTn_lAw wrote::D "yay, me wanna make big multishot pnoob with 1000 psi foot pump compressor using diamond as main material. Do you think wet bread make good sealant? " :D
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

Unread postAuthor: Cosmic Muffin » Tue Feb 28, 2012 11:11 am

Hahaha that's so bizarre Jack. Which show is that from? I'm familiar with him in Peepshow. That's such a great show. I'm thinking of making a trigger and sear from Perspex. Is that anywhere near as strong as nylon?
  • 0

User avatar
Cosmic Muffin
1st Lieutenant
1st Lieutenant
 
Posts: 275
Joined: Mon Jan 14, 2008 10:30 pm
Location: arse end of nowhere
Reputation: 0

Unread postAuthor: wyz2285 » Tue Feb 28, 2012 12:49 pm

Only whatched the video now... :puke:
I don´t know much about Perspex, but the nylon I use is pretty strong.
  • 0

CpTn_lAw wrote::D "yay, me wanna make big multishot pnoob with 1000 psi foot pump compressor using diamond as main material. Do you think wet bread make good sealant? " :D
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

Sponsored

Sponsor
 


Unread postAuthor: wyz2285 » Sun Mar 11, 2012 11:51 am

Sorry for double post.
I made this counter-balanced hammer valve design, with parts I can make/find.
The seal/counter piston has the same OD, witch means there is no area for the pressure to working on, only the spring to keep the valve closed(witch means I need a weak hammer, and possibility for semi/full).
But, will it "dump"? I think no because there is the spring to push the stem.
The seal/counter piston has a OD of 10mm, at 50 bar it would be very powerful :D .
I don´t see any problem about this design, but before I start making it I´d like to hear your guys opinion.
  • 0

Attachments
valve.jpg
valve.jpg (31.24 KiB) Viewed 719 times
CpTn_lAw wrote::D "yay, me wanna make big multishot pnoob with 1000 psi foot pump compressor using diamond as main material. Do you think wet bread make good sealant? " :D
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

Unread postAuthor: the unit » Sun Mar 11, 2012 1:05 pm

Once it opens it will drain all the pressure in the firing and reserve chambers until it is equal to the force of the spring.
  • 0


the unit
Specialist
Specialist
 
Posts: 51
Joined: Tue Jun 24, 2008 8:20 pm
Reputation: 0

Unread postAuthor: wyz2285 » Sun Mar 11, 2012 2:42 pm

You sure? There is still area of the sealing, with a weak hammer it shouldn´t let all the air out, but it is a problem, as the valve doesn´t work as a regulator anymore :? witch means huge power at high pressure and low power at low pressure, as the valve opening time is the same...I will need a ajustable striker.
  • 0

CpTn_lAw wrote::D "yay, me wanna make big multishot pnoob with 1000 psi foot pump compressor using diamond as main material. Do you think wet bread make good sealant? " :D
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

Unread postAuthor: Goats spudz » Sun Mar 11, 2012 2:50 pm

a piece of metal got inside my fridgy a piece of file snapped while i was filing the edge it got in the secondary input where the oil goes, its not going to explode and kill me if i try fill my pcp is it? (ran it for 5 Mins no problem)
  • 0

Where's my Chuck key?

Goats spudz
Lieutenant Colonel
Lieutenant Colonel
 
Posts: 458
Joined: Tue Aug 02, 2011 12:31 pm
Reputation: 0

Unread postAuthor: Crna Legija » Sun Mar 11, 2012 8:15 pm

what in gods name made you post that here?
  • 0

'' To alcohol... The cause of, and solution to, all of life's problems.”
--Homer Simpson

Add me on ps3: wannafuk, 8/11/11 cant wait
User avatar
Crna Legija
Major General
Major General
 
Posts: 2333
Joined: Sun Jul 20, 2008 5:14 am
Location: australia
Reputation: 0

Unread postAuthor: Gippeto » Sun Mar 11, 2012 10:39 pm

Image

Going to agree with the unit...as drawn it'll dump.

Wouldn't use an o-ring to seal on the striker side of the spool either...the pressure will get under it at the instant it is free to do so, and blow it right out of it's groove. Could cage the o-ring (see techs qdv for an example of caged o-rings), but that won't stop it from "puffing" up and rubbing/slicing on the opening/cage...o-ring life will be affected.

Would be better to use a partially balanced spool, and use the larger end of the spool to seal. This'll take care of the dumping problem and the o-ring issue. Look up BTB's "push button valve" if you're unsure what a partially balanced spool is.

You actually WANT the valve to close sharply to get a short blast of air behind the projectile...too much dwell time, and the valve is still open after the projectile has left the barrel. YES...maximum power will be achieved, but at the cost of using WAY more air than needed.


I see you're also planning to use screws in shear, so....here's a little bonus reading material for ya. :wink: Shear strength is typically 60% of Tensile strength (I use Yield)...if you cannot find compressive strength of a material, use the yield strength when calculating bearing stress. I use a minimum safety factor of 3 at yield.


http://courses.washington.edu/mengr356/ ... -joint.pdf
  • 0

"It could be that the purpose of your life is to serve as a warning to others" – unknown

Liberalism is a mental disorder, reality is it's cure.
User avatar
Gippeto
Donating Member
Donating Member
 
Posts: 2393
Joined: Sat Jan 19, 2008 10:14 am
Location: The Great White North...Canada eh!
Reputation: 11

Unread postAuthor: wyz2285 » Mon Mar 12, 2012 3:14 am

Thanks Gippeto
Ok I will try to fix the valve... But I don't know if I can find a new seal.
No I won't use screws in shear, not strong enough, they will have to deal with 200kg.
  • 0

CpTn_lAw wrote::D "yay, me wanna make big multishot pnoob with 1000 psi foot pump compressor using diamond as main material. Do you think wet bread make good sealant? " :D
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

Unread postAuthor: Gippeto » Mon Mar 12, 2012 11:27 am

Screws in shear is an EASY design to calculate...used by many folks...myself included. I posted that link for a reason. :wink:

Plenty strong if done "right". :)
  • 0

"It could be that the purpose of your life is to serve as a warning to others" – unknown

Liberalism is a mental disorder, reality is it's cure.
User avatar
Gippeto
Donating Member
Donating Member
 
Posts: 2393
Joined: Sat Jan 19, 2008 10:14 am
Location: The Great White North...Canada eh!
Reputation: 11

PreviousNext

Return to Pneumatic Cannon Database

Who is online

Registered users: Bing [Bot], Google [Bot], mrfoo, MSNbot Media, Yahoo [Bot]

Reputation System ©'