Is this a burst disc?

[bduares]

I suddenly am getting a leak in my Sumatra 2500 from the end of the tank plug, and I think the culprit may be this part. There was no bang, and the part does not look busted, but it holds air right up to a certain psi then starts leaking from the end that holds this thing. Not a big air dump, just a steady hiss of air getting past this thing. If it is a burst disc does anyone know where I might find a replacement? It seems to be about 11.75mm in diameter.

[ranchibi]

Looks like one...they are flat when new so that one looks either defective or it did its job and now leaks. Once they warp or burst they will not seal.

[Killfire]

Looks like a burst disk to me. You need to measure the thickness. The yield pressure is determined by thickness. Too thin and it will pop early. Too thick and it may not pop when it is supposed to.

[bduares]

The tube diameter it fits in is 12 mm. But I do not see where to order this type of disc anywhere, with the exception of Kral discs that are only in the  8 mm size range.

[louigi600]

It sure looks like a burst disk but when they burst they are supposed to rupture permanently and not hold pressure to a certain point.
Was the special bolt holding it in place loosened or something ? because when I was fiddling with the burst disks on an external regulator the bolt holding the disk in place was pretty "dang" tight ... they probably need to be torqued to some spec. I remember I was unable to loosen the bolt with a normal wrench ,,, had to o buy a 1/4" ratchet bit, which is not common in Europe, else the bolt was going to become almost round with the normal wrench.

[bduares]

On a Sumatra it is a pretty large grub screw that holds the disc in the very end of the middle tube. At the other end of the tube is the poppet valve and hammer. The large grub screw has a hole drilled in the threading by the factory. When I now fill the gun even with the grub screw in as tight as it can be, air leaks out from that spot. The diameter of the threaded hole that holds the burst disc and grub screw is 12mm. I am assuming the burst disk, when it is flat, is supposed to be 12mm, but now it has lost a half mm due to the bubble that formed in the center of it so air now gets past it.

I spoke to Air Venturi and they managed to find me a replacement burst disc which is now on the way. I also found some 12mm steel discs that are .04 inches thick which are a backup contingency in case the disc that AV sent does not do the trick. Between those and the copper disc on the way hopefully they will let the gun keep pressure. I might even use both types at once. My final option will be to try to find a grub screw without the threading hole, so the end can be more permanently sealed. 2 of the 3 options will of course disable the ability of the gun to have an emergency pressure relief function at that junction but that would be preferable to not being able to retain air pressure at all.

[SILENT SQUIRREL]

I wonder if making your own burst discs is worth a try.
Perhaps doing this by finding the proper thickness material and punching them out a hollow punch of the diameter needed.
Has anyone tried this?

Edward

[Privateer]

I've read somewhere of people using a soda can to punch out burst disks.
Don't recall what they were used for but I'd think one can figure out a good material and make thier own.

[Back_Roads]

I've read somewhere of people using a soda can to punch out burst disks.
Don't recall what they were used for but I'd think one can figure out a good material and make thier own.

Yes there is also copper sheets that come in various thicknesses, One would need a specific burst pressure disk then match the thickness.

[Privateer]

Yes there is also copper sheets that come in various thicknesses, One would need a specific burst pressure disk then match the thickness.

I'd tend to think it wouldn't be that hard to build some sort of tester also.

[SILENT SQUIRREL]

I've read somewhere of people using a soda can to punch out burst disks.
Don't recall what they were used for but I'd think one can figure out a good material and make thier own.

Badimer (Baltimore) air gunners will insist that Pabst Blue Ribbon cans, and only Pabst Blue Ribbon cans will work, hon

just my too been there
Edward

[Privateer]

I've read somewhere of people using a soda can to punch out burst disks.
Don't recall what they were used for but I'd think one can figure out a good material and make thier own.

Badimer (Baltimore) air gunners will insist that Pabst Blue Ribbon cans, and only Pabst Blue Ribbon cans will work, hon

I'd rather jump outta perfectly good areoplane then buy that stuff.
Oh wait! I have jumped outta perfectly good areoplanes!
 

[Back_Roads]

I've read somewhere of people using a soda can to punch out burst disks.
Don't recall what they were used for but I'd think one can figure out a good material and make thier own.

Badimer (Baltimore) air gunners will insist that Pabst Blue Ribbon cans, and only Pabst Blue Ribbon cans will work, hon

just my too been there
Edward

Good to know, most of my neighbors drink that.

[bduares]

I received the new 3 pack of burst discs from Air Venturi today. The original disc was 12mm, The tube it seals is 12mm. But the 3 discs sent to me are 8mm. um.....

I sent them an email with a photo of the old and new discs together asking if they sent the wrong thing to the wrong people.

[louigi600]

I wonder if making your own burst discs is worth a try.
Perhaps doing this by finding the proper thickness material and punching them out a hollow punch of the diameter needed.

Building a burst disk is not difficult at all but getting the right material and thickness to make it burst at a relatively precise pressure may require a lot of testing. Good luck.
You may want the disk to burst somewhat close but under the hydro-static test pressure (normally 1.5 times the max working pressure).

[nervoustrigger]

I've made replacement burst disk diaphragms with sheet stock and a hollow punch.  It's a trial and error affair...not hard to do, just potentially time consuming.

My first experience was making a replacement for a 13ci Ninja paintball tank because I had set the regulator up for 1500psi and the OEM one (marked 1.8k) let go.  I punched out some samples from an aluminum soda can (0.005" thick) and tested a few samples to failure and they each ruptured somewhere between 2000-2100psi.

Be advised material and thickness are not the only variables at your disposal but also the size of the opening the disc bears against.

To anyone wishing to make their own, I can't emphasize strongly enough how important it is to test multiple samples to failure for confidence it will rupture before pressures reach a potentially dangerous level.