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Premature Ejecting Problem.

Post questions and info about pneumatic (compressed gas) powered cannons here. This includes discussion about valves, pipe types, compressors, alternate gas setups, and anything else relevant.
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Premature Ejecting Problem.

Unread postAuthor: boyntonstu » Fri Oct 16, 2009 8:28 am

I muzzle load a tight fitting projectile.

When I pressurize the chamber, air gets to the barrel before the piston seals and the projectile prematurely ejects slowly out of the barrel.

I use a piece of soft PEX tubing as the ramrod.

I thought of tying a cord to the PEX that could be used to retain the projectile during pressurizing.

Once pressurized, I could loop the cord over a fixed point to retract it safely from the barrel.

I would never muzzle load a 500 psi cannon.

Other than building a breech loading port, is there a better solution?

BoyntonStu

EDITED BY PCGUY - Changed it to the word "eject".
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Unread postAuthor: jeepkahn » Fri Oct 16, 2009 8:38 am

Use a spring behind the piston to push it closed when there's no pressure...

Use a spring that has just enough umph to push the piston up against the barrel...

JSr and myself use piston springs frequently...
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Re: Premature Ejaculation Problem.

Unread postAuthor: Technician1002 » Fri Oct 16, 2009 10:57 am

boyntonstu wrote: the projectile prematurely ejaculates slowly out of the barrel.
BoyntonStu


I think you are looking for the word ejects. The other is a sexual problem. Sorry to hear about it but this is the wrong forum for medical problems.
:D
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Re: Premature Ejaculation Problem.

Unread postAuthor: boyntonstu » Fri Oct 16, 2009 1:22 pm

Technician1002 wrote:
boyntonstu wrote: the projectile prematurely ejaculates slowly out of the barrel.
BoyntonStu


I think you are looking for the word ejects. The other is a sexual problem. Sorry to hear about it but this is the wrong forum for medical problems.
:D


The spring helps my medical problem.

Do you suffer with premature ejectulation with your little cannon?

Use a spring?
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Unread postAuthor: POLAND_SPUD » Fri Oct 16, 2009 2:04 pm

wait till JSR comments on that... or a feminist
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Unread postAuthor: jackssmirkingrevenge » Fri Oct 16, 2009 2:28 pm

I didn't want to comment too early :D
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Re: Premature Ejaculation Problem.

Unread postAuthor: Technician1002 » Fri Oct 16, 2009 3:00 pm

boyntonstu wrote:
Do you suffer with premature ejection with your little cannon?

Use a spring?


No, It's plumbing works just fine.


I would never muzzle load a 500 psi cannon.

Other than building a breech loading port, is there a better solution?


It is one of the reasons I built the ABS Cellular Core test cannon to shoot apples. Projectiles that seal the barrel caused lots of problems with trapped air while loading. The QDV style piston was left unsealed through the middle to solve this issue. I have left the piston unsealed around the control rod or pull rope to aid in loading. It works well. The QDV was designed to solve several traditional piston problems. Trapped air and getting an initial seal were two of them it solved.

A small bleed hole can be drilled at the breech of the barrel in external piston valves. Coax is much harder to get a proper bleed vent.
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Re: Premature Ejaculation Problem.

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Unread postAuthor: psycix » Fri Oct 16, 2009 3:16 pm

Do you fill from the pilot or the chamber side?

How is the piston fit?
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Unread postAuthor: Brian the brain » Fri Oct 16, 2009 3:25 pm

I didn't want to comment too early


You meant to say "prematurely"

Reminds me of that Vietnam movie with Sean Penn saying:
"This is a rifle-this is a gun
This is for shooting-this is for fun..."


Could someone add this word to the list of censored words?

A lot of 14 year olds on here you know...
Although I had quite a giggle over this mistake.. :roll: :shock: :D
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Oh my friggin god stop being so awesome, that thing is pure kick ass. Most innovative and creative pneumatic that the files have ever come by!

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Unread postAuthor: Ragnarok » Fri Oct 16, 2009 11:07 pm

Brian the brain wrote:Could someone add this word to the list of censored words?

If we do that, can we also provide an auto fix for "cumbustion"? :roll:
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Unread postAuthor: cheeseboy » Sun Oct 25, 2009 4:44 am

A lot of 14 year olds on here you know...

hehe ! :D

but on a relevant note, just adding that you can also fill with a larger volume pump for the first few pumps, it should prevent that from happening, but putting a spring behind the piston is worth it so long as the spring isn't too strong, because you can also fill from the chamber, which is easier, as well as being more ergonomic IMHO.
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Unread postAuthor: Willdebeers » Sun Oct 25, 2009 6:32 am

Ragnarok wrote:
Brian the brain wrote:Could someone add this word to the list of censored words?

If we do that, can we also provide an auto fix for "cumbustion"? :roll:


That made my day :D
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Unread postAuthor: mark.f » Sun Oct 25, 2009 2:58 pm

My suggestion is to learn to relax.

No, seriously.

I had this problem with a piston launcher when shooting potatoes. I would fill the launcher very slowly and I'd have no problems.
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Unread postAuthor: AngryChauncey » Sun Oct 25, 2009 8:53 pm

One thing I did was put a 1/4 in. ball valve behind the projectile, which you open while are loading it, and close when you are ready to fire.
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