Will this be too dangerous? or will it work?

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Bedo
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Thu Aug 18, 2005 11:54 pm

Im having a real hard time getting hairspray to explode in my combustion chamber.
It has a really strong spark dead center in the chamber.

So i was wondering if i could use starting eether as a propellant.

but i am really worried that it will make my cannon explode which is made out of pvc.

thanks in advance
spudshot
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Fri Aug 19, 2005 8:20 am

it depends, is your chamber made out of pressure rated pipe? did you use primer and cement? did you use 2 screws wired to the ignitor to jump the gap?

if you answered yes to all of them you should be fine using it.

really you're probably using too much hairspray (which i wouldnt recommend because it gums up the chamber, try rightguard in the brown can instead) if you do decide to use starting fluid you need the smallest spray possibly, split second will be enough for a chamber
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Bedo
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Fri Aug 19, 2005 11:20 am

the chamber is 4" piping which isnt pressure rated but i wrapped it in 60 yards of duct tape =)

i used primer and cement and i used 2 screws.

so can i use the starting eether or not because my tube isnt pressure rated?
Cole
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Fri Aug 19, 2005 11:56 am

Well duct tape is pressure rated to 5 psi so that really isnt going to help at all.
spudshot
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Fri Aug 19, 2005 12:52 pm

i wouldnt use it, your pipe is Cellular core and is not meant to take pressure, the duct tape wont do a damn thing
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Bedo
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Fri Aug 19, 2005 3:33 pm

ok.
thx for the help. i guess i'll go buy sopme rightguard soon and try to get it to work

EDIT: I wrapped it with duct tape so that if it exploded it wouldnt break into tiny pieces of shrapnel
pyrogeek
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Thu Aug 17, 2006 2:12 am

Bedo wrote:ok.
thx for the help. i guess i'll go buy sopme rightguard soon and try to get it to work

EDIT: I wrapped it with duct tape so that if it exploded it wouldnt break into tiny pieces of shrapnel
Actually, if it did rupture you will probably just make it worse. When you confine an explosion it becomes stronger. Kind of like firecrackers. You light one just like it comes out of the package, and it will be pretty weak. But, if you wrap it with tape it is louder, because it has better confinement.

If you want to make you gun safer you could tape it up so if it bursts, it will split in two. Or have some sort of weaker spot where it will fail first, and the whole gun won't explode into a million peaces.
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boilingleadbath
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Thu Aug 17, 2006 2:25 am

Pyrogeek, there are BIG differences between a rupture of a pressure vessle once the pressure-production mechanism is nearly compleate, and the confinement of a solid explosive.

Also, "tape" doesn't provide two shits worth of confinement on these scales. Tensile strength/volume is really poor, and I garantee they won't put it on as thick as the chamber.
And it won't increase the bursting point (noticably) because tape is 'stretchier' than PVC (the tensile modulus is lower). Devide and conquer, you know...

Anyway, short of milling grooves in the chamber, I think it's going to be hard to change the fragmentation pattern.
However, the concept of putting a large-bore burstdisk on the end of the chamber away from the barrel has been proposed before, which shares many similar features.
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