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Burst Disk?

Posted: Sat Feb 23, 2008 6:08 pm
by Counterstriker
I am new to Burst disk guns but not to valves.
Could someone gimme an idea on how they work maybe a diagram? I am not asking for ideas just the concept of these bad boys. I have a Idea but I want to confirm it.

Posted: Sat Feb 23, 2008 6:12 pm
by MaxuS the 2nd
Well all it is really is when the pressure inside the chamber reaches a certain pressure, a disk made from Aluminium Foil or Plastic (among other materials) breaks and releases all of the stored pressure, giving the fastest flow coefficient.

Posted: Sat Feb 23, 2008 6:17 pm
by MrCrowley
Check the spud wiki, more then enough information. Still have trouble, search the forum. Topics like this aren't needed when we have so much information on them already.

Posted: Sat Feb 23, 2008 6:17 pm
by Counterstriker
Thanks! I sorta had that in mind. Could I use Aluminium tape?

Posted: Sat Feb 23, 2008 6:38 pm
by MaxuS the 2nd
Test different materials to see what works for you.

Posted: Sat Feb 23, 2008 7:07 pm
by DYI
You really just have to test burst pressures. I can give you a rough idea for tinfoil disks though, as I've used them (very) extensively myself. All of these numbers are for standard thickness, "Our Compliments" brand household aluminum foil.

1" (nominal size) unions:
4 layers - very low. below 100 psi. A rough estimate is 70 psi
8 layers - below 200 psi (vague, I know)
16 layers - consistently between 450 and 500 psi

1.5" (nominal size) unions:
4 layers - ~20 psi
8 layers - ~70 psi
16 layers - ~160 psi
32 layers - between 400 and 450 psi

2" (nominal size) unions:
24 layers - ~160 psi (just tested this 2 hours ago)

All of these burst pressures have been tested, although the 1.5" data will be the most accurate because I've tested and used it the most. I'm upgrading my main gun to 2" porting, so more figures for it will come soon. The figures with a ~ sign in front of them are ones that I've actually pressurised slowly until they burst, and will be the most accurate. The others are ones I've used in triggered designs (using figures extrapolated from actual tests), so I don't have any definitive numbers on them.

Posted: Sat Feb 23, 2008 7:57 pm
by potatoflinger
With a .5" union, two layers of standard bike inner-tube rubber will burst at around 150 psi.

Posted: Sat Mar 01, 2008 10:21 am
by Counterstriker
Well I made a basic design but the only problem is when I pump it up te barrel flys off because of the pressure.. I have pvc with threads but that rips it. Should I make some sort of locking device?

This is kinda what it looks like..

Image

Posted: Sat Mar 01, 2008 10:33 am
by Jared Haehnel
Make your burst disk let go at a lower pressure. Any idea what psi It blows off at?

If its ripping right through the threads... your threads probably aren't gripping very well and are not making a good seal. Which is dangerous. Why don't you replaced the pop bottle with a PVC or metal chamber?

Posted: Sat Mar 01, 2008 2:47 pm
by Counterstriker
Jared Haehnel wrote:Make your burst disk let go at a lower pressure. Any idea what psi It blows off at?

If its ripping right through the threads... your threads probably aren't gripping very well and are not making a good seal. Which is dangerous. Why don't you replaced the pop bottle with a PVC or metal chamber?

Woops I described it wrong.. There are no threads on it yet I am just using a connector and putting the disk between it. I was asking if the threading will rip the aluminium while screwing it on? Sorry for the bad description :D .

Posted: Sat Mar 01, 2008 2:50 pm
by windshrike
No, it shouldn't tear the disk(unless you've got a pretty messed up union!!).

Posted: Sat Mar 01, 2008 2:53 pm
by Counterstriker
windshrike wrote:No, it shouldn't tear the disk(unless you've got a pretty messed up union!!).
Ok sounds good. I might go out and get the pieces.. If I am not a lazy ass..

Posted: Sat Mar 01, 2008 2:53 pm
by Jared Haehnel
If you use a union to place the aluminum foil disk in and then tighte the union then no the treads shouldn't rip the disk any... (they shouldn't even be touching the treads.)

If you try and put the aluminum foil over the treads its not likely to screw on very well and even then your right the threads wouldn't do the aluminum any good.

Posted: Sat Mar 01, 2008 3:00 pm
by Counterstriker
What exactly is this union thing you speak of?

Is this what your saying is a "No No"

Posted: Sat Mar 01, 2008 3:03 pm
by Jared Haehnel
I'm thinking of a PVC union that looks like this...

http://www.sisale-international.com/pro ... 135013.htm

hope that helps

:)