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My 1st Burst disk.

Built a pneumatic cannon? Then post it here! This section is for completed, finished cannons that you have built. Please include pictures and information.
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Unread postAuthor: Counterstriker » Sat Mar 08, 2008 7:35 pm

Yah it is, Thank for your help.


And DYI I don't know how many layers, If you read my first post that says its still drying.
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Unread postAuthor: Hubb » Sat Mar 08, 2008 7:44 pm

When I was testing my hybrid, I used aluminum foil. 4 layers burst at around 30 - 35psi. And that was a 1" union. If you plan on running it at 100 - 150 psi, you may want to consider the pop cans or other material.
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Unread postAuthor: Counterstriker » Sat Mar 08, 2008 8:00 pm

hubb017 wrote:When I was testing my hybrid, I used aluminum foil. 4 layers burst at around 30 - 35psi. And that was a 1" union. If you plan on running it at 100 - 150 psi, you may want to consider the pop cans or other material.


Yah I think I will pop and beer cans. I just gotta test them tommorow. I don't have a PSI meter on my cannon, on my old bike pump I did but it broke.
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Unread postAuthor: BigGrib » Sat Mar 08, 2008 8:33 pm

I used one of those plastic disks that are in the caps of soda bottles the big one litre wide mouths, i just cant remember what the burst at.
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Yea, that's definitely going to get you at least a tazer.

<a href="http://www.youtube.com/watch?v=AkMkGOpAF4s">DONT TAZE ME BRO.. DONT TAZE ME... AHHHH</a>
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Unread postAuthor: Hubb » Sat Mar 08, 2008 9:01 pm

BigGrib wrote:I used one of those plastic disks that are in the caps of soda bottles the big one litre wide mouths, i just cant remember what the burst at.


His union looked as if it was too big for one of those.
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Unread postAuthor: DYI » Sat Mar 08, 2008 9:05 pm

Let me rephrase my question: In the video, there were burst disks sitting on the glass table, and they looked like they were for a 2" union. How many layers of aluminum foil were they?

Aluminum foil makes a fine burst disk material. I believe I listed this somewhere else, but in a 2" union, you're going to need about 16 layers for 100 psi, and probably 20 or 22 for 150 psi burst pressures, considering that 24 layers bursts around 170 psi.
To make them in bulk, find the longest flat floor space you can, and then roll it all the way along, then double back over so that it's 2 or even 4 layers thick before you start folding. Takes a while to get used to, but you could easily make more than 30 2" disks in one batch using this method.
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Unread postAuthor: Counterstriker » Sun Mar 09, 2008 11:59 am

Well, I made them 1 at a time :D . I was getting used to the Xacto. they were single layers but I plan on putting 10+ at a time. I have to go back to homedepot in a bit to get exoxy putty because the reducer gets in the was when I try to launch something out out.
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Unread postAuthor: DYI » Sun Mar 09, 2008 2:25 pm

And finally, after about a page of responses, my first question has been answered :D Thank you.

Your going to need to make these things in bulk though, because you'll need 16 layers even for 100 psi, and at least 20 layers for 140.
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Unread postAuthor: Counterstriker » Sun Mar 09, 2008 2:34 pm

DYI wrote:And finally, after about a page of responses, my first question has been answered :D Thank you.

Your going to need to make these things in bulk though, because you'll need 16 layers even for 100 psi, and at least 20 layers for 140.


Yah :lol: didn't understand.. But it doesn't even work.. Cause the union sucks dick.. Look at my Bad union topic please.
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Unread postAuthor: OuchProgramme » Sun Mar 09, 2008 8:51 pm

Counterstriker wrote:
DYI wrote:And you still never said how many layers thick the disks were...

You can certainly make a gun without GGDT, but you'll waste a lot more money on optimisations and R&D in general, and your guns won't turn out as well. Also, you'll constantly be asking questions and clogging up the forum with things that could be accomplished by a few clicks on GGDT. Constantly running simulations is the only way I've kept the cost of the SCTBDC manageable, really.

If you have the knowledge to run all the calculations GGDT does on your own, then congratulations.


Dude. why are you getting mad at me? I can't load it.. it won't let me.. Whats the forum for If I can't ask questions.. I never shot it yet so I don't know how many layers I will need.


Chill.

I believe DYI is asking how many layers you're planning to use
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Unread postAuthor: Counterstriker » Mon Mar 10, 2008 7:40 pm

OuchProgramme wrote:
Counterstriker wrote:
DYI wrote:And you still never said how many layers thick the disks were...

You can certainly make a gun without GGDT, but you'll waste a lot more money on optimisations and R&D in general, and your guns won't turn out as well. Also, you'll constantly be asking questions and clogging up the forum with things that could be accomplished by a few clicks on GGDT. Constantly running simulations is the only way I've kept the cost of the SCTBDC manageable, really.

If you have the knowledge to run all the calculations GGDT does on your own, then congratulations.


Dude. why are you getting mad at me? I can't load it.. it won't let me.. Whats the forum for If I can't ask questions.. I never shot it yet so I don't know how many layers I will need.


Chill.

I believe DYI is asking how many layers you're planning to use


If you read on you could see we ended the argument..
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Unread postAuthor: OuchProgramme » Mon Mar 10, 2008 8:22 pm

Yeah i see :wink:


Its drying for an awful long time
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Unread postAuthor: Counterstriker » Mon Mar 10, 2008 8:30 pm

OuchProgramme wrote:Yeah i see :wink:


Its drying for an awful long time


:D Yah I have been trying to work the kinks out of it.. (leaking union) I found a pretty good sollution.
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Unread postAuthor: Counterstriker » Tue Mar 11, 2008 6:45 pm

Hey I got a vid in!! The only reason it didn't go through the box is because I used soft ammo..

[youtube]http://www.youtube.com/watch?v=0CPAnIelS44[/youtube]

1 layer of plastic bag, 3 layers of foil, yes only 3.. Anything past that leaks like no tommorow. I am still working on mortar ammo... And nail just pokes a hole in it which causes it to leak out rather than make the disk go BOOM!
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Unread postAuthor: DYI » Tue Mar 11, 2008 8:05 pm

Not exactly impressive, but 3 layers of foil in a 2" union works out to about 10 psi, so the the low performance is to be expected. I wouldn't be surprised if the disk failed before the needle of the gauge even moved enough to get a reading.

Also, I'm not trying to lure you into the SCTBDC trap, but you really need a longer barrel.
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