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The SBDP (simple burst disk pneumatic)
Posted: Wed May 14, 2008 6:33 pm
by Acdcmonkey1991
It's been a long time since I've posted a cannon, so I thought it was time to make a simple burst disk pneumatic just to test the efficency of using a burst disk. I am actually pretty surprised, at about 100 psi it went through 2 sheets of drywall, with a clean entry and exit. I might put up damage pics later but for now just pictures. I still have not recieved my 1 1/4 in. to 3.8 in. reducer from mcmaster yet, which I will add when I get it because I think it will give the gun a more overall smooth look.
Specs:
C:B ratio- 1:2 (I think)
Ammo- 3.8 in. steel ball bearings
Burst disk- 7 sheets of wax paper (I ran out of Alum. foil)
Barrel- Aluminum, 3/8 in. 3 feet long
Chamber- all steel, 19 inches with fittings
Posted: Wed May 14, 2008 6:37 pm
by jrrdw
Wax paper, interesting. Never heard of using that before. Good work!
Posted: Wed May 14, 2008 6:41 pm
by Acdcmonkey1991
It works pretty well. I wanted to get a test done tongiht, and I was out of aluminum foil so I just thought , hey, why not?
Posted: Wed May 14, 2008 6:52 pm
by bigbob12345
cool, reminds me of my
BDMS
Nice job
Though the chamber is probably a little overkill. You will lose not more than 50fps if you make the chamber half the size.
Posted: Wed May 14, 2008 8:04 pm
by JDP12
yea a bit overkill IMHO... but still nice gun
Posted: Thu May 15, 2008 5:07 pm
by Acdcmonkey1991
Overkill because of the steel parts?
Update: got the reducer
Posted: Thu May 15, 2008 5:21 pm
by bigbob12345
No, overkill becasue of the chamber size relitive to the barrel size.
Posted: Fri May 23, 2008 5:06 am
by Carlman
hey mate,
does your union seal 100%?
i have made something similar with a galvanized steel union and it still leaks even with bike inner tube for gasket.
thanks man.
Posted: Fri May 23, 2008 6:24 am
by jrrdw
Carlman wrote:hey mate,
does your union seal 100%?
i have made something similar with a galvanized steel union and it still leaks even with bike inner tube for gasket.
thanks man.
Try o-rings, sometimes a minor miscut will cause a leak and will be very hard to find exact cause.
Posted: Fri May 23, 2008 9:21 am
by starman
Are you using a trigger device to initiate the burst or just filling with air until it bursts? From the gun's apparent simplicity, it appears to be the latter.
Drywall is not going to offer very substantial resistance as target material, even 2 or 3 layers. Try some 3/4" plywood and "2 by" material and see what you get.
Posted: Fri May 23, 2008 10:37 am
by Carlman
its all good now thnx jrrdw
im using packing tape and it seals 100%
with no orings or gasket
Posted: Fri May 23, 2008 2:29 pm
by Acdcmonkey1991
What I did to get it to seal is an o-ring I found that fits perfectly, btw starman, it wasnt drywall, it wazs cement board.