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pengun deluxe

Built a miniature cannon? Then post it here! This section is for completed, finished cannons that you have built. Please include pictures and information.
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Unread postAuthor: theBOOM » Sat Jul 31, 2010 9:28 am

Eh today my first coaxial mini is curing :D it's in the oven right now, speeding up the process.

EDIT: Jack, do I need to add a bumper onto small coaxials like this???
Right now I have 3 pistons in mind, one that is made out of plastic, very light but might crack after long periods of use, casting one out of hot glue, or casting one out of epoxy. I just want something that will last me a while.
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Unread postAuthor: jackssmirkingrevenge » Sat Jul 31, 2010 10:11 am

Insomniac wrote:I tried it a moment ago... it maintains structural integrity all the way up to 160psi, and I got about three or four successful pilots from it.. but now the piston ain't sealing right. I used a solid bit of rubber from an eraser, which I think is too soft.


Possibly. Also note how I usually add reinforcement to the breech end of the barrel in order to better support the piston and reduce wear, an important consideration when it is impossible to replace it.

Oh well... I'll stick the arse end of it in hot water to soften the glue and try again!


That's one benefit over epoxy I suppose ;)

Eh today my first coaxial mini is curing :D it's in the oven right now, speeding up the process.


Mom must be delighted ;)

do I need to add a bumper onto small coaxials like this???
Right now I have 3 pistons in mind, one that is made out of plastic, very light but might crack after long periods of use, casting one out of hot glue, or casting one out of epoxy. I just want something that will last me a while.


Depends on the piston. A solid rubber piston is its own sealing face and bumper so no worries there. If your piston has the potential to damage itself, a simple o-ring the same diameter as the inside of your chamber should suffice.
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Unread postAuthor: Insomniac » Sat Jul 31, 2010 8:08 pm

Well, turns out I was right. My barrel sliced right into my piston. I just tried again with a harder rubber (hot glue is amazing for prototypes!), and it lasted longer but the same thing happens. Interestingly, it maintained functionality all the way up to failure... the only clue that it was cutting through was the increasing delays between piloting and firing. Eventually as I pumped it up it just spat out a barrel-sized cutout of my piston from the barrel. Oh well.

My problem is that I'm using a bit of a teloscoping antenna from an RC transmitter as the barrel... that stuff is THIN, and I didn't add any kind of support around it. Oh well, once I get some more tubing I'll try again.
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Unread postAuthor: jackssmirkingrevenge » Sat Jul 31, 2010 10:35 pm

Insomniac wrote:My problem is that I'm using a bit of a teloscoping antenna from an RC transmitter as the barrel... that stuff is THIN, and I didn't add any kind of support around it. Oh well, once I get some more tubing I'll try again.


There's your problem! Well, either reinforce the breech, or put the seal on the breech itself and you can even use a solid piston.
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Unread postAuthor: Insomniac » Sat Jul 31, 2010 11:01 pm

I think I'll wait till I buy some proper tubing and try again :D

You use 6mm tube for your penguns don't you? Do you do anything to the schrader to make it fit more snugly first, or do you just use plenty of epoxy to seal the gap?
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I wonder how much deeper the ocean would be without sponges.
Right now I'm having amnesia and deja vu at the same time. I think I've forgotten this before.

Add me on msn!!! insomniac-55@hotmail.com
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Unread postAuthor: jackssmirkingrevenge » Sat Jul 31, 2010 11:12 pm

Insomniac wrote:Do you do anything to the schrader to make it fit more snugly first, or do you just use plenty of epoxy to seal the gap?


Plenty of epoxy :) though I do sometimes wrap the end with some tape strips to stop epoxy entering the chamber.
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Unread postAuthor: Insomniac » Sun Aug 01, 2010 12:08 am

Well... I just finished V3 (using the same parts as V1 and V2... the wonders of hot glue!).

I've added considerable support around the barrel for the piston to rest on, and even added heat shrink on the outside to cover the unsightly hot glue which is slowly covering the entire thing. I expect this one to work, and last for at least a little while.

My only worry is that when I shrunk the heat shrink, it melted the glue for long enough for it to drip into the internals. Time will tell!
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Right now I'm having amnesia and deja vu at the same time. I think I've forgotten this before.

Add me on msn!!! insomniac-55@hotmail.com
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Unread postAuthor: jackssmirkingrevenge » Sat Sep 18, 2010 6:35 am

Here's the latest in the series which I made as a prize for the Fall 2010 best shot contest, still have to make a cap as a firing mechanism, will make some videos then.
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Unread postAuthor: jakethebeast » Sat Sep 18, 2010 7:07 am

thats fantastivly cool :D :D
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Unread postAuthor: jackssmirkingrevenge » Sat Sep 18, 2010 8:15 am

Make a decent video and it could be yours ;)

Here it is in action at 350 psi:

[youtube]http://www.youtube.com/watch?v=sYN2lP1Uwfc[/youtube]
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Unread postAuthor: Fnord » Sat Sep 18, 2010 12:11 pm

Ya know, it would be fun/dangerous to just leave one of those laying around in an office - loaded.


...how do I click this pen...?
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Unread postAuthor: jackssmirkingrevenge » Sat Sep 18, 2010 7:58 pm

Fnord wrote:Ya know, it would be fun/dangerous to just leave one of those laying around in an office - loaded.


Since when was it either/or :D
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Unread postAuthor: Insomniac » Sat Sep 18, 2010 8:33 pm

Fnord wrote:Ya know, it would be fun/dangerous to just leave one of those laying around in an office - loaded.


...how do I click this pen...?


[youtube]http://www.youtube.com/watch?v=ye4kqjLOY7M[/youtube]

:D

If it wasn't for the fact someone would probably lose an eye, it would be hilarious to try this. Oh well.
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I wonder how much deeper the ocean would be without sponges.
Right now I'm having amnesia and deja vu at the same time. I think I've forgotten this before.

Add me on msn!!! insomniac-55@hotmail.com
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Unread postAuthor: jackssmirkingrevenge » Sun Sep 26, 2010 12:42 am

Update on the contest pengun, added a cap for firing :)
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Unread postAuthor: ilovefire » Sun Sep 26, 2010 12:58 am

looks good, really should make another one of these there quite fun to make :)
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