I need help with my Pen Gun

[PotatoEnemy17]

I'm starting my second pneumatic cannon and it is a pen gun type thing. My problem is the piston won't seal onto the barrel. I used wd40 but it didn't help much. The barrel is a piece of an arrow shaft. The chamber is aluminum pipe. and the piston is a little piece of round plastic that fit in the chamber well. It has a bit of red rubber glued on the end of it. I've never posted on spudfiles before, so I might not get the photo attachment thing right.

[Fnord]

Usually a piston will leak if the barrel or sealing face isn't squared up correctly. You could also try using grease on the piston rather than wd40; it usually seals a little better.

How did you make the barrel removable?


<edit: 2k posts. Yeehaw wasted time

[Gun Freak]

Yeehaw wasted time

As Fnord said, make sure its all square and clean, if the barrel isn't clean where the piston rests it probably won't seal.

[jackssmirkingrevenge]

WD40 and rubber seals are a bad idea, in fact most lubricants tend to make the problem worse. How about a solid rubber piston? Easy to cut with a section of sharpened chamber tubing.

<edit: 2k posts. Yeehaw wasted time

[PotatoEnemy17]

Usually a piston will leak if the barrel or sealing face isn't squared up correctly. You could also try using grease on the piston rather than wd40; it usually seals a little better.

How did you make the barrel removable?


<edit: 2k posts. Yeehaw wasted time

The barrel is not actually removable, I had to un-glue it. I guess I'll try solid rubber.

[jackssmirkingrevenge]

is the barrel properly centred? some advice on how to guarantee it here: http://www.spudfiles.com/forums/epoxy-c ... t8916.html

[sagthegreat]

sometimes when you go up to higher pressures, the rubber will compress onto the barrel and make a seal, it has worked for me

[PotatoEnemy17]

Thanks for the help. I made a hot glue piston and I have epoxyed evereything together now, I just have to wait for it to dry.