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new cannon help

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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new cannon help

Unread postAuthor: jmeyer1022 » Tue Nov 11, 2008 5:25 pm

plan so far is to take

Image


On one end ill put a cleanout which will have a valve for filling

Off the 2 sides I'll put 45 degree bends then another 45 degree bend which will go to a 2 foot chamber on each side with end caps.

Directly across from the cleanout cap I'll put the barrel which will be about 4-5' 1.5 inch SDR 21 for golfballs.

Within that 4 way fitting I want to host a 3" piston to block the barrel from receiving air and the chambers fill up until I release the 2nd valve and making the piston perform. My 2 issues I see.

The 4 way fitting has a sort-of groove in it, will I need to sand this down for the piston to slide?

Then what is good to make a 3" piston out of?
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Unread postAuthor: FishBoy » Tue Nov 11, 2008 5:34 pm

I think it will work, and probably quite well (if done properly).

I don't think you understand pistons though, the barrel should extend about into the middle of the "X", and the piston fits into the peice of pipe that the pilot connects to. When you fill, the piston slides forward and extends into the "X" and seals against the barrel.
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Unread postAuthor: Hubb » Tue Nov 11, 2008 5:50 pm

This, basically, would be a double chambered pneumatic and has been done plenty of times so, yes, it would work.

As far as the piston operation, read what FishBoy said.

One thing I did notice is the word "cleanout." A cleanout is a DWV fitting and is not suitable for pneumatics.
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Unread postAuthor: starman » Tue Nov 11, 2008 5:56 pm

This has been used before successfully, usually with 2 separate "supa" type valves. A single piston will be more of a challenge because of the slop in the cross design. Your piston will just have to be larger.
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Unread postAuthor: jmeyer1022 » Tue Nov 11, 2008 6:15 pm

Ya I understand the barrel will make its way about halfway into the 4 way connector. Any ideas for a piston for this?
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Unread postAuthor: FishBoy » Tue Nov 11, 2008 6:18 pm

I'm not sure, you could find an endcap of some size that fits inside 3" pipe, or use something else. mr. Crowley always seems to know what to make pistons out of.
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Unread postAuthor: jmeyer1022 » Tue Nov 11, 2008 6:50 pm

I think I'm going to get a 3" endcap and sand the threads down
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Unread postAuthor: SpudsMcGee » Tue Nov 11, 2008 9:37 pm

jmeyer1022 wrote:I think I'm going to get a 3" endcap and sand the threads down

What you can do is get an internal end cap (pvc plug).
It looks like this:
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Unread postAuthor: jmeyer1022 » Tue Nov 11, 2008 9:42 pm

fill it with hot glue?
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Unread postAuthor: SpudsMcGee » Tue Nov 11, 2008 9:51 pm

Or just pvc cement...
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Unread postAuthor: EphOph » Tue Nov 11, 2008 11:07 pm

Wouldn't epoxy be the best thing with which to fill it? Hot glue could work but it's rather nasty and doesn't stick too well, and I've noticed that PVC cement tends to shrink when it dries.
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Unread postAuthor: starman » Tue Nov 11, 2008 11:09 pm

jmeyer1022 wrote:fill it with hot glue?


Too heavy.

SpudsMcGee wrote:Or just pvc cement...


Uuuuhh NO.... If anything epoxy.
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