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 66 users online :: 5 registered, 0 hidden and 61 guests


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

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

The Team
Administrators
Global Moderators
global_moderators.png CS

Copperheads new barrel - 4mm bore for biro cartridge darts

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

Copperheads new barrel - 4mm bore for biro cartridge darts

Unread postAuthor: Hotwired » Tue May 01, 2007 6:14 am

Firstly the 4mm barrels are 60cm fibreglass tent poles with an 8mm OD and a 4mm ID and the yellow coupling used to join them is a cut down and dremel lathed core of one of these:
Image

A picture walkthrough of the build :wink:

Image
Image
Image
Image
Image
Image
Image
Image
Image
Image

The darts are the brass nibbed plastic tubes inside ball point pens with the rear end slit a few mm and flared out. They can punch through as many cardboard boxes as you can be bothered to put in front of it or through a 5mm softwood plank :)
  • 0

User avatar
Hotwired
Lieutenant General
Lieutenant General
 
Posts: 2599
Joined: Fri Oct 13, 2006 5:51 am
Location: UK
Reputation: 0

Unread postAuthor: experament-u2 » Tue May 01, 2007 7:05 am

hehehehheheh kool
  • 0

User avatar
experament-u2
Lieutenant Colonel
Lieutenant Colonel
 
Posts: 469
Joined: Tue Dec 26, 2006 11:18 pm
Reputation: 0

Unread postAuthor: zeigs spud » Tue May 01, 2007 4:23 pm

very nice. looks professionaly great! :D
  • 0

User avatar
zeigs spud
Colonel
Colonel
 
Posts: 657
Joined: Tue Apr 04, 2006 10:39 pm
Reputation: 0

Unread postAuthor: pyromaniac » Tue May 01, 2007 4:26 pm

nice. can you still have its old barrel? or will it be shooting pens forever now.
  • 0

:pottytrain3:
User avatar
pyromaniac
Brigadier General
Brigadier General
 
Posts: 805
Joined: Tue Feb 27, 2007 7:18 pm
Location: MO
Reputation: 0

Unread postAuthor: chaos » Tue May 01, 2007 5:02 pm

it must be very fun to cap cans and stuff.....hmmm may i ask you now how you get more than one shot off a fill?

have you though about putting a scope/sight on it?
  • 0

User avatar
chaos
Brigadier General
Brigadier General
 
Posts: 1205
Joined: Wed Jan 17, 2007 8:31 am
Reputation: 0

Unread postAuthor: jackssmirkingrevenge » Wed May 02, 2007 3:56 am

Nice, though you probably could have joined a third length of tent pole and have a real high velocity penetrator, you certainly have the spare chamber capacity.
  • 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: Hotwired » Wed May 02, 2007 4:00 am

I can switch barrels on it still, the one I used for the outer shell of this had a tiny dent halfway along so it was pretty crap if I was using tight fitting ammo. It was just lying about so I decided to give it another go :)

I can also do nail darts with tape or unravelled string tails. Theres a number of holes through a 1/2" plank now... and a hole in my celing when I managed to press the trigger instead of the safety :oops:

Chaos I've not made my semi yet, the only hint I'll give is that all you can see on the cannon is all I'm using. Obvious perhaps but sometimes it needs to be said.
  • 0

User avatar
Hotwired
Lieutenant General
Lieutenant General
 
Posts: 2599
Joined: Fri Oct 13, 2006 5:51 am
Location: UK
Reputation: 0

Sponsored

Sponsor
 


Unread postAuthor: jackssmirkingrevenge » Wed May 02, 2007 4:47 am

If you only exhaust a small amount of the pilot chamber, the piston will reseal before the chamber has time to empty, not sure if that's what you´re getting at...
  • 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: Hotwired » Wed May 02, 2007 4:56 am

I didn't notice your first post Jack: I already had the 1m copper barrel so it wasn't really possible to attach more poles after it - I have a suspicion the reduction of bore to 4mm is pushing the air towards the speed of sound - definitely a sharpish noise when firing.
  • 0

User avatar
Hotwired
Lieutenant General
Lieutenant General
 
Posts: 2599
Joined: Fri Oct 13, 2006 5:51 am
Location: UK
Reputation: 0

Unread postAuthor: jackssmirkingrevenge » Wed May 02, 2007 5:01 am

You really should try going for higher pressure, with just 12 inches of barrel at 400 psi I had managed this.

It's a great design and I don't see why it shouldn't hit near-subsonic velocity with light enough ammunition. My only gripe would be the extra pilot volume but I suppose you have to sacrifice some performance for ergonomic´s sake :wink:

edit: another small tip, with higher pressures the pilot blowgun is going to harder to operate, perhaps an actual trigger would be a good idea to spread the weight over your finger and make it less of an 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: Hotwired » Wed May 02, 2007 5:52 am

I can feel the difference between 240psi and 0psi but it doesn't seem to be causing much of a problem - I wear a black cotton glove on my grip hand so my finger slides over the trigger as it's pulled instead of sticking.

A shock pump will be on my shopping list as soon as I find a way to attach it - I'm using a presta valve and shocks take schraders I believe...
  • 0

User avatar
Hotwired
Lieutenant General
Lieutenant General
 
Posts: 2599
Joined: Fri Oct 13, 2006 5:51 am
Location: UK
Reputation: 0

Unread postAuthor: jackssmirkingrevenge » Wed May 02, 2007 5:57 am

  • 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: Hawkeye » Wed May 02, 2007 5:59 am

I guarantee you won't have the patience to pump up a chamber that size with a shock pump. Even topping it up after filling it with a track pump will be an ordeal. Since you are using copper and JFC, why don't you make your own?
  • 0


Hawkeye
Lieutenant Colonel
Lieutenant Colonel
 
Posts: 462
Joined: Sun Jan 21, 2007 7:12 pm
Reputation: 0

Unread postAuthor: jackssmirkingrevenge » Wed May 02, 2007 6:04 am

Hawkeye wrote:I guarantee you won't have the patience to pump up a chamber that size with a shock pump. Even topping it up after filling it with a track pump will be an ordeal.


Ordeal :shock: come on, where's your cojones? Besides, it's good exercise :D
  • 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: Hotwired » Wed May 02, 2007 11:20 am

Exercise shmexcersice, I do this for the fun of it :wink:

I've already got a couple of those things jack but the bloody things leak like hell :roll:

Maybe they're low quality.
  • 0

User avatar
Hotwired
Lieutenant General
Lieutenant General
 
Posts: 2599
Joined: Fri Oct 13, 2006 5:51 am
Location: UK
Reputation: 0

Next

Return to Pneumatic Cannon Database

Who is online

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

Reputation System ©'