SpudFiles

At 30 psi I lose 3-5 psi in one minute. I'm wondering if you all are having better luck then me? Tommorow I'm going to try and use a gasket insted of an oring, They may be more soft and fix the potential problem of subtle mis alignment.

It depends on your disc material, and which way you hook up the union too, they're unidirectional.

Mine seals perfectly with a cable grommet and aluminium tape.

They leak?

My burst disks never leak, until they burst. Maybe it's the way I have mine set up? Using a PVC union and a rubber o-ring with aluminum disks:


You can view the whole topic here.

I use a rubber gasket and aluminum foil in a 1/4 steel union, with the "male" union piece ground down. It holds perfectly to 150 psi, and once I get my spark plug I'll be able to test it up to 600 (I don't have a great way to seal where the spark plug goes, so the shock pump is too slow for the leak there)

Mine never leaks either, if it leaks I'll re-assemble the burst disk for another shot as the leak will through the mix off.

I've used a variety of combinations over the years. Gaskets are great but tend to get damaged after awhile and o-rings are pretty good too but are prone to being shot out the barrel. My current setup has been the most successful yet: I grounded down the union half with the cone so that it is flat and threaded that part to the barrel; I stack o-rings inside the union half attached to the chamber (make sure the o-rings are the same diameter as inside the union fitting) until the top o-ring is half inside the union and half poking out; put the disks on top of this o-ring and thread on the union half attached to the barrel.

Because the o-rings inside one union half are much larger in diameter than the hole through the middle of the union attached to the barrel, the o-rings have no place to go and aren't shot down the barrel.

What are you using for your fitting? Screw together 2 piece union like cowscankill pictured or cam lock like Sgort87 commonly uses?

Mine will lose about 1/2 psi every 30 minutes.

For a chamber that size, that's a hell of a leak

D_Hall wrote:Mine will lose about 1/2 psi every 30 minutes.

When you say "mine" do you mean VERA?

Very similar to this configuration, just PVC.



One problem is that the male peice rotates when in fact all you need is compression. The rotation will score the burst disk as it is tightened and means it'll rupture at 20 psi instead of 60 psi.

So I got to make the pipe float inside of the male adapter so the burst disc won't get chewed up. Just how a union works...

A union is a fitting that allows a threaded joint without requiring the joined pipes to be rotated.

Cut the tapered part off another male fitting, so you lose no length in the cut, face them both off, stone both faces to a mirror finish, then lubricate one face, and reassemble it. They slide against each other, and you have no problems at all.

O-ring>burst disk>flat washer>male piece. That way nothing is spinning against the burst disk and you have a nice flat sealing face...

jackssmirkingrevenge wrote:

D_Hall wrote:Mine will lose about 1/2 psi every 30 minutes.

When you say "mine" do you mean VERA?

Yes.

It's not really an issue though... She doesn't get fueled until she's ready to fire and she gets fired within seconds of being fueled (a process itself that only takes a couple minutes).

And honestly? I'm not even 100% sure she's leaking. Experience in other endeavors tells me that when you pump up a pressure vessel, the pressure will drop a small amount simply due to cooling of the oh-so-recently compressed gas.

But I've not done the proper experiments so I'm willing to call it a leak, even if it isn't (I don't really know).

Well I cut a rubber sheet out like this:
It is only leaking 1 psi every 5 minutes at 30 psi. Yeah!



HOLY F*ING SH*T
(russian zorbing)