coupler burst disk M72 law

Show us your pneumatic spud gun! Discuss pneumatic (compressed gas) powered potato guns and related accessories. Valve types, actuation, pipe, materials, fittings, compressors, safety, gas choices, and more.
iknowmy3tables
Staff Sergeant
Staff Sergeant
United States of America
Posts: 1596
Joined: Fri Dec 15, 2006 3:57 pm
Location: maryland
Has thanked: 3 times
Been thanked: 9 times

Fri Aug 31, 2018 4:47 pm

Hey spudfiles long time no see,
http://www.spudfiles.com/pneumatic-cann ... 24557.html
my at4 recently died on me, I'm not sure how but the toolies valve piston got bent and permanently lodged itself in the gun. I don't have access to a lathe anymore to remake it so in the mean time I thought I should make something way more simple to fill the niche.

some of you might remember the airsoft burst disk launchers and Davidvaini pre-loaded cartridges
http://www.spudfiles.com/pneumatic-cann ... 16727.html
http://www.spudfiles.com/pneumatic-cann ... 15021.html

I want to cram a simple bust dist launcher in an empty M72 Law rocket launcher tube I own and I want it to be able to launch nerf aero flyer/vortex footballs.

I'm entirely new to this style of bust disk launcher so far I've made a prototype with a chamber that has 14 inches of 1" pvc as a chamber and the burst disk is fitted in a 1 inch coupler, the low volume and opening presure couldn't puch objects out of a 12 inch test barrel.

I'd like to know if anyone still here has experience or tips on building this type of pneumatic particularly
is my goal of launching nerf footballs with this mechanism is feasible?
what coupler size should the burst disk be based on?
and this may sound silly, but is there a particularly good popular brand of foil for burst disk guns so I can get the bursting pressure up?
iknowmy3tables
Staff Sergeant
Staff Sergeant
United States of America
Posts: 1596
Joined: Fri Dec 15, 2006 3:57 pm
Location: maryland
Has thanked: 3 times
Been thanked: 9 times

Fri Aug 31, 2018 10:54 pm

well it appears I made some progress, I bought some Reynolds wrap heavy duty foil wrapped my nerf footballs with some masking tape and squeezed it into 1.5" pvc
so far I learned I can loosen the coupler fit to handle more layers of foil just by rubbing the pipe with acetone
Image
Image
Image

at the moment I only have a co2 inflator in my apartment so I don't know the pressure that the disks are bursting at but I'm using 3-4 layers and footballs are launching as hard as I can throw them maybe more. this is just a rough prototype for now, I'm still working on the dimensions and practicing setting up the burst disks so they don't burst prematurely
iknowmy3tables
Staff Sergeant
Staff Sergeant
United States of America
Posts: 1596
Joined: Fri Dec 15, 2006 3:57 pm
Location: maryland
Has thanked: 3 times
Been thanked: 9 times

Sun Sep 16, 2018 3:01 pm

I finally got a chance to update this project, i changed it to a 1.5" chamber with a .5" coupler and pipe for the burst disk, this seems to preform fine even just with one layer of foil.
Image
Image
Image
Image
it's pretty crude but I think I got what I want out of this project
User avatar
jackssmirkingrevenge
Five Star General
Five Star General
Posts: 26179
Joined: Thu Mar 15, 2007 11:28 pm
Has thanked: 543 times
Been thanked: 319 times

Donating Members

Mon Sep 17, 2018 9:19 am

Good stuff! Can't help feeling that there must have been a bigger diameter you could have used for more efficiency but hey, it works!
hectmarr wrote:You have to make many weapons, because this field is long and short life
iknowmy3tables
Staff Sergeant
Staff Sergeant
United States of America
Posts: 1596
Joined: Fri Dec 15, 2006 3:57 pm
Location: maryland
Has thanked: 3 times
Been thanked: 9 times

Mon Sep 17, 2018 10:28 am

Yeah I shrunk the burst disk size to in theory increase rupture pressure and have less burst disk material overall all to hopefully make this more reliable. this method for burst disks is pretty limited and can only handle 3 layers of foil at most, also with friction alone holding the pipe I thought a smaller diameter made sense
Post Reply