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 :: 3 registered, 0 hidden and 63 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

MBDC - 500 psi handheld burst disk gun

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

MBDC - 500 psi handheld burst disk gun

Unread postAuthor: DYI » Mon Dec 24, 2007 5:47 pm

This is just a spare parts gun I threw together last week. Chamber is 30 ci, barrel is .787" x 61".

Fired by opening filling ball valve, which fills the chamber to 500 psi in a few seconds. After firing, the valve has to be closed immediately to prevent very expensive and violent gas loss.

Muzzle energy is 410 ft/lbs @ 630 fps for 30 gram slug, and 460 ft/lbs @ 430 fps for 70 gram slug.

Pictures. The first picture shows the slugs I used. The little ones are 30 grams and filled with ball bearings, and the big one is 70 grams total and houses a 60 gram steel dart.
Image
The valve setup.
Image
The cannon resting on my hardened steel plate backstop.
Image
Picture of the full cannon, in all its horribly discoloured glory.
Image

And a few short clips. The first two shots are with the 30 gram slugs, and the last one is with the 70 gram slug. That board is made out of some strange material and is A LOT tougher than it looks.
[youtube]http://www.youtube.com/watch?v=8l9DtwuVN2E[/youtube]
  • 0

Spudfiles' resident expert on all things that sail through the air at improbable speeds, trailing an incandescent wake of ionized air, dissociated polymers and metal oxides.
User avatar
DYI
Lieutenant General
Lieutenant General
 
Posts: 2861
Joined: Sat Jul 07, 2007 8:18 pm
Location: The People's Republic of Canuckistan
Country: Turks and Caicos Islands (tc)
Reputation: 9

Unread postAuthor: Hotwired » Mon Dec 24, 2007 6:10 pm

Hardened steel plate backstop?

Looks like a wooden board with a large hole in it to me :P

Mind you. I think you're a bit close to be firing at a steel plate. If I'm firing at close range I use a tunnel of fibre mat to catch the inevitable rebound and since I've found riccochets buried deep in the lawn I'm a bit cautious about it.

The firing shots sound pretty nice. A more sophisticated disk mechanism might be a good thing if possible.
  • 0

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

Unread postAuthor: Hailfire753 » Mon Dec 24, 2007 6:13 pm

416 FPL ?!!111ONE??? Amazing! Are you using CO2? What do you use for the burst disk?
  • 0

UPDATED MARCH '08
field-legal paintball semi
User avatar
Hailfire753
Captain
Captain
 
Posts: 348
Joined: Thu Jun 28, 2007 11:50 pm
Location: Near Philadelphia, PA
Reputation: 0

Unread postAuthor: DYI » Mon Dec 24, 2007 6:30 pm

The plywood with a hole in it is just what I hang the plate on. The plate doesn't cover the whole sheet of plywood, so you can see through the hole.

I wasn't firing at the steel, I was firing at more than 1" of the mystery board mentioned in my original post, plus another 3/4" of plywood.

416 FPL ?!!111ONE??? Amazing! Are you using CO2? What do you use for the burst disk?


The power isn't really that exciting. The SCTBDCv1.5 will do over 6000 ft/lbs (no typo).

CO2 is one of most useless gases conceivable for pneumatic propulsion. I use a 2400 psi industrial nitrogen tank regged down to 500.

The burst disk is 16 layers of aluminum foil, which generally fails between 450 and 500 psi.
  • 0

Spudfiles' resident expert on all things that sail through the air at improbable speeds, trailing an incandescent wake of ionized air, dissociated polymers and metal oxides.
User avatar
DYI
Lieutenant General
Lieutenant General
 
Posts: 2861
Joined: Sat Jul 07, 2007 8:18 pm
Location: The People's Republic of Canuckistan
Country: Turks and Caicos Islands (tc)
Reputation: 9

Unread postAuthor: Killjoy » Tue Dec 25, 2007 4:14 am

Thats pretty cool.
I like the part in the video when one of the projectiles rolls in front of the camera, it's like one of those tumbleweeds in those westerns that always roll across the street before a duel. Clearly the plywood lost this one.
  • 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

Unread postAuthor: carter » Tue Dec 25, 2007 4:22 am

holy s#!t. i like it alot. but i'm not to sure on your filling system. wouldn't it be better if you filled the camber then used a ball valve to crack the foil? because you might not be getting the pressure your thinking
  • 0

At my lemonade stand I used to give the first glass away free and charge five dollars for the second glass. The refill contained the antidote

carter
Corporal
Corporal
 
Posts: 77
Joined: Mon Mar 05, 2007 2:47 am
Reputation: 0

Unread postAuthor: jackssmirkingrevenge » Tue Dec 25, 2007 10:14 am

Again, that poor shed, but it shows that with a bit of high pressure for brute force, you don't need a sophisticated construction :)
  • 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: DYI » Tue Dec 25, 2007 3:13 pm

holy s#!t. i like it alot. but i'm not to sure on your filling system. wouldn't it be better if you filled the camber then used a ball valve to crack the foil? because you might not be getting the pressure your thinking


If I did that, the opening time of the ball valve would cut performance hideously. This way, as soon as the whole chamber reaches the right pressure, the disk blows. Kind of like pumping it until it bursts, but a bit more sophisticated.

Yeah, this is about as simple as it gets while still having semi-decent power.
  • 0

Spudfiles' resident expert on all things that sail through the air at improbable speeds, trailing an incandescent wake of ionized air, dissociated polymers and metal oxides.
User avatar
DYI
Lieutenant General
Lieutenant General
 
Posts: 2861
Joined: Sat Jul 07, 2007 8:18 pm
Location: The People's Republic of Canuckistan
Country: Turks and Caicos Islands (tc)
Reputation: 9

Unread postAuthor: elitesniper » Thu Dec 27, 2007 12:58 pm

can we get a picture of the burst disk bursted already :D
  • 0

User avatar
elitesniper
Brigadier General
Brigadier General
 
Posts: 1090
Joined: Sat Oct 13, 2007 8:40 pm
Reputation: 0

Unread postAuthor: mark.f » Thu Dec 27, 2007 1:18 pm

Why? It probably just looks like this.

Except with 4x more layers of foil.
  • 0

Attachments
disks.jpg
User avatar
mark.f
Donating Member
Donating Member
 
Posts: 3464
Joined: Sat May 06, 2006 11:18 am
Country: United States (us)
Reputation: 21

Unread postAuthor: elitesniper » Thu Dec 27, 2007 1:54 pm

wow my disk didnt burst like that mines ripped :( well i think thats beacuse i dont have a union yet its just clamped in threded fittings
  • 0

User avatar
elitesniper
Brigadier General
Brigadier General
 
Posts: 1090
Joined: Sat Oct 13, 2007 8:40 pm
Reputation: 0

Unread postAuthor: mark.f » Thu Dec 27, 2007 3:22 pm

Yeah... kind of off-topic, but the smoothest aluminum foil will ever look in it's life, (besides when it's already on the roll), will be when it's clamped in a union with pressure on one side. Makes almost a perfect convex mirror. :wink:

These came out of a steel union with a neoprene gasket to seal.
  • 0

User avatar
mark.f
Donating Member
Donating Member
 
Posts: 3464
Joined: Sat May 06, 2006 11:18 am
Country: United States (us)
Reputation: 21

Unread postAuthor: DYI » Thu Dec 27, 2007 4:48 pm

Mine uses a butyl rubber gasket and a steel union. I don't have any of the bursted disks around, I just throw them out when I replace them.

Most of my bursted disks just look like the one on the left of Mark's picture, but with four neat "petals" at 90 degrees to the rest of the disk.

In comparison, the front disk on the SCTBDC after a shot just looks like a perfect ring of foil. There are no loose pieces attached, just a thin ring where it sealed on the outside.
  • 0

Spudfiles' resident expert on all things that sail through the air at improbable speeds, trailing an incandescent wake of ionized air, dissociated polymers and metal oxides.
User avatar
DYI
Lieutenant General
Lieutenant General
 
Posts: 2861
Joined: Sat Jul 07, 2007 8:18 pm
Location: The People's Republic of Canuckistan
Country: Turks and Caicos Islands (tc)
Reputation: 9

Unread postAuthor: jackssmirkingrevenge » Fri Dec 28, 2007 1:00 am

The past tense of burst is burst, therefore a disk which has burst is a burst disk, not a "bursted" disk - because technically, before it's been fired, it's just a... well, "disk" ;)

This post was brought to you courtesy of the grammar Nazis :D

Image
  • 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: DYI » Fri Dec 28, 2007 2:15 pm

I used bursted to avoid confusion. You are slightly wrong though: they are called burst disks before they have burst, and they should be called "burst burst disks" after they have been burst. But that would get a lot more confusing than just writing "bursted disks", which is grammatically incorrect, but probably no more so than " burst burst disks", however not as much so as "bursted burst disks" (which is also slightly less confusing than "burst burst disks"). Chew on that one for a while JSR :lol:
  • 0

Spudfiles' resident expert on all things that sail through the air at improbable speeds, trailing an incandescent wake of ionized air, dissociated polymers and metal oxides.
User avatar
DYI
Lieutenant General
Lieutenant General
 
Posts: 2861
Joined: Sat Jul 07, 2007 8:18 pm
Location: The People's Republic of Canuckistan
Country: Turks and Caicos Islands (tc)
Reputation: 9

Next

Return to Pneumatic Cannon Database

Who is online

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

Reputation System ©'