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 58 users online :: 3 registered, 0 hidden and 55 guests


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

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

The Team
Administrators
Global Moderators
global_moderators.png CS

Coax Question

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

Coax Question

Unread postAuthor: ShowNoMercy » Mon Oct 01, 2007 8:31 pm

I have a few questions regarding the construction of a coax cannon.
1) Has anyone attempted to utilize more than one barrel inside the chamber?
2) Do I have to use a coupler and a bushing for the ends of the chamber or is there a way to use a bushing straight into the chamber?
3) If I were to build a coax with a 2" chamber, would a 1 " sprinkler valve be overkill?

Thanks
  • 0

Jesus saves, no need to pray
The gates of pearl have turned to gold
It seems you've lost your way
User avatar
ShowNoMercy
Brigadier General
Brigadier General
 
Posts: 1094
Joined: Mon Mar 19, 2007 8:08 am
Location: Jersey Bitches!
Reputation: 0

Unread postAuthor: mopherman » Mon Oct 01, 2007 9:47 pm

(1) no, lack of proper fittings has prevented that.
(2) yes, you must use a coupler and bushing. Unless you can find a bushing that fits quite well.
(3) no i dont think it would be overkill. I think it would pilot quite well.
  • 0

searching for a modern day savior from another place,inclined toward charity,everyone's begging for an answer,without regard to validity,the searching never ends,it goes on and on for eternity
-Bad religion
User avatar
mopherman
Brigadier General
Brigadier General
 
Posts: 788
Joined: Sat Feb 03, 2007 8:20 pm
Reputation: 0

Unread postAuthor: Hotwired » Mon Oct 01, 2007 11:28 pm

(1) It is possible with copper fittings - there are 22mm -> 2/3/4 x 8/10mm fittings
(2) You dont get (pressure rated) Reducing Couplers where you are?
(3) What mopher said :wink:
  • 0

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

Unread postAuthor: spudgunnerwryyyyy » Mon Oct 01, 2007 11:55 pm

1) dual barrels would require custom epoxy casting.
2) epoxy casting would work great
3) Pilot valve size is not a matter of over kill its more a matter of performance versus cost. But that would work great for that chamber.
  • 0

User avatar
spudgunnerwryyyyy
1st Lieutenant
1st Lieutenant
 
Posts: 261
Joined: Thu Jul 12, 2007 10:54 pm
Reputation: 0

Unread postAuthor: ShowNoMercy » Tue Oct 02, 2007 2:53 pm

Has anyone heard of or used Starboard? I have a lot of it at work and I was wondering if anyone had used it in a spudgun before. Its made from recycled plastic and I can get it in 1/4 and 1/2 sheets, similar to plywood. So I am thinking of making a coax piston and bushings for the ends out of it.
  • 0

Jesus saves, no need to pray
The gates of pearl have turned to gold
It seems you've lost your way
User avatar
ShowNoMercy
Brigadier General
Brigadier General
 
Posts: 1094
Joined: Mon Mar 19, 2007 8:08 am
Location: Jersey Bitches!
Reputation: 0

Unread postAuthor: jackssmirkingrevenge » Tue Oct 02, 2007 10:14 pm

spudgunnerwryyyyy wrote:1) dual barrels would require custom epoxy casting.


Indeed I often though about doing this but always found it better to just use a single large barrel and use a sabot to fire multiple projectiles.
  • 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: Lentamentalisk » Tue Oct 02, 2007 11:48 pm

@hotwired
I think he is talking about a bushing, the ones that go inside the big pipe, not a reducing coupling, though it does seem more practical to use a reducing coupling, given that there are no bushings that actually fit in the pipe, since they have the same OD as the pipe, so require a coupler like he was talking about.
  • 0

User avatar
Lentamentalisk
Brigadier General
Brigadier General
 
Posts: 1202
Joined: Tue Aug 07, 2007 5:27 pm
Location: Berkeley C.A.
Reputation: 0

Sponsored

Sponsor
 


Unread postAuthor: Killjoy » Wed Oct 03, 2007 12:53 am

A 3"-2" bushing fits well in 4" pipe, I did that for an unfinshed coax and it worked great.
  • 0

Stanford Class of 2012

"In the end our society will be defined not only by what we create, but what we refuse to destroy"- John Sawhill

Killjoy
Brigadier General
Brigadier General
 
Posts: 1053
Joined: Sun Nov 12, 2006 12:51 am
Location: New Mexico
Reputation: 0

Re: Coax Question

Unread postAuthor: frankrede » Wed Oct 03, 2007 2:24 am

ShowNoMercy wrote:I have a few questions regarding the construction of a coax cannon.
1) Has anyone attempted to utilize more than one barrel inside the chamber?
2) Do I have to use a coupler and a bushing for the ends of the chamber or is there a way to use a bushing straight into the chamber?
3) If I were to build a coax with a 2" chamber, would a 1 " sprinkler valve be overkill?

Thanks
I believe #1 has been done, I'm not sure though
  • 0

Current project: Afghanistan deployment
User avatar
frankrede
Lieutenant General
Lieutenant General
 
Posts: 3220
Joined: Thu Jul 20, 2006 9:47 pm
Reputation: 0

Re: Coax Question

Unread postAuthor: jackssmirkingrevenge » Wed Oct 03, 2007 2:31 am

frankrede wrote:I believe #1 has been done, I'm not sure though


luckythirteen on spudtech had made a twin-barrelled cloud but I don't remember anything larger.
  • 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: ShowNoMercy » Wed Oct 03, 2007 11:50 am

I think I am going to go for two barrels, probably the 1/2 inch CPVC stuff. Since I will be using a piece of plastic instead of bushings I can make however many barrels I want to, however I plan on using a 2inch pipe for the chamber, do you think that with two barrels in it the volume available may not be enough?
  • 0

Jesus saves, no need to pray
The gates of pearl have turned to gold
It seems you've lost your way
User avatar
ShowNoMercy
Brigadier General
Brigadier General
 
Posts: 1094
Joined: Mon Mar 19, 2007 8:08 am
Location: Jersey Bitches!
Reputation: 0

Unread postAuthor: jackssmirkingrevenge » Wed Oct 03, 2007 12:08 pm

even if the barrel's o/d was 1 inch, having 2 barrels in a 2 inch chamber would still give you a C:B ratio greater than 1:1 if your barrel was as long as your chamber, so you should be fine.
  • 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

Return to Pneumatic Cannon Discussion

Who is online

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

Reputation System ©'