Air cannon leaks..

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joepage2008x2
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Wed Mar 17, 2010 9:53 am

thats 314lb of force on that endcap when at 100psi, I think your risking your health at these pressures or go for a thicker PVC
nosnik
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Wed Mar 17, 2010 10:24 am

whoooaaaaa!!! are u serious? 314lb of force? crazy im going to reduce the air chamber. and replace the current one with thicker pvc. but how would i know what too use?
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dewey-1
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Wed Mar 17, 2010 10:29 am

The VU series is for drainage purposes not potable (drinking) water.
Do not use VU series for your launcher! Very dangerous to use.

For others to see; VUDL50
http://translate.google.com/translate?h ... n%26sa%3DG

Here is HT series equivalent. Note wall thickness!
http://translate.google.com/translate?h ... n%26sa%3DG

You definitely need to research for proper fittings and pipe.
Sorry to bring bad news to your efforts!
joepage2008x2
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Wed Mar 17, 2010 10:34 am

area of circle = pi x r x r
the area of the 2" end cap is 3.14" therefore 100lb per square inch = 314lb which also = very scary.
377lb at 120psi
Your not the only one, i used to fill 2L coke bottles with 200psi.

I dont have anything to do with PVC (only ever used metal) and dont do cannons anymore due to the law in my country, the others on this forum should know. I do remember someone talking about PVC gas pipe thats rated at 150psi.
nosnik
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Wed Mar 17, 2010 10:34 am

so i was not even using PVC?? @Dewey-1 its not bad news. this is in fact very good news for me! thanks!
another Question1 is class E safe too use?

[edit]@Joe its not a really large one and i have no intention of bring it out of my house (air cannons are /maybe?/ legal in my country) but still thanks :)
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MrCrowley
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Wed Mar 17, 2010 4:59 pm

Question1 is class E safe too use?
In Australia/New Zealand we used to (and sometimes still do) use the "Class" system, A being the lowest pressure rated and F being the highest. Anything from Class D-F is safe to use in a low pressure pneumatc (0-120PSI).

Not sure if it is the same system, but that's what I know about the class system here.
nosnik
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Wed Mar 17, 2010 7:53 pm

thats great mr.croweley!! ty :) hopefully its the same or ill have a loud bang and curious neighbours again
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Marffy
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Wed Mar 17, 2010 9:42 pm

i'd use tire slime/sealer. i used it on my cannon and it works.
"Hard work has a future pay-off. Laziness pays off now."
nosnik
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Wed Mar 17, 2010 10:50 pm

i made a new chamber and im letting it set for now
it works up to 40 psi but i did not test it above that cause 1. it has not set completely 2. im afraid the 15mm pvc might explode :oops:
but i know it has a leak where the tire valve is (im using one from a road bike tire. the really slim ones)
any ideas on how high i can bring the pressure for 15mm pvc ?

thanks
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MrCrowley
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Wed Mar 17, 2010 10:53 pm

it works up to 40 psi but i did not test it above that cause 1. it has not set completely 2. im afraid the 15mm pvc might explode
What part of "wait for glue to cure fully before testing with pressure" do you not understand? That's probably the reason you have leaks in the first place. You should never, ever test a cannon with pressure until the glue has had the full 24 hours to cure.

Did you even use primer?

I really think you need to slow down and figure out what you're doing and learn about safety before making cannons. Did you use pressure rated pipe and fittings this time?
any ideas on how high i can bring the pressure for 15mm pvc
As high as it says. Don't tell me you haven't checked the pipe to see its pressure rating?
nosnik
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Wed Mar 17, 2010 11:06 pm

:oops: well it says Class E on the pipe then the rest got sawed off.. primer? well i cleaned the parts before use and im using Pvc glue... :cry: im sorry :(
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heres the pvc glue im using .. i cant read japanese so i dont know wat to call it<br />:/
heres the pvc glue im using .. i cant read japanese so i dont know wat to call it
:/
4.jpg (38.54 KiB) Viewed 1902 times
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