Crowley's First Co-ax - Update

Show us your pneumatic spud gun! Discuss pneumatic (compressed gas) powered potato guns and related accessories. Valve types, actuation, pipe, materials, fittings, compressors, safety, gas choices, and more.
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MrCrowley
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Fri Mar 07, 2008 8:17 pm

New Pics :)
The power from such a crappy design impressed me, I have plans for a 3/4" chamber, 24" 6mm barrel and possibly mounted to a rifle stock.


I made this as sort of a proto-type. Just so I could get some experience with co-axials.

Specs:

1" Chamber 12" long
6mm Barrel 16" long
Wooden Dowel Piston with O-ring.

Until I make a high pressure pump, I have a QC on it for my compressor. I'll switch to schrader when I make the pump.

I know it's way over kill, but it's just parts I had laying around. And it needs a longer barrel, but I need to find a hobby store that stocks some.

And JSR before you go off about the Pilot Volume, there is next to none. The piston is housed in about 6cm of 20mm PVC that's sleeved in the metal chamber. The PVC extends back into the reducer, giving the piston about 7mm to travel. The rest of the pilot volume is taken up by some rubber which doubles as a bumper.

Picture time...

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Last edited by MrCrowley on Sun Mar 30, 2008 11:49 pm, edited 1 time in total.
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elitesniper
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Fri Mar 07, 2008 8:20 pm

Very nice job Mr.C! i demand to see some damage! :x
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MrCrowley
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Fri Mar 07, 2008 8:23 pm

elitesniper wrote:Very nice job Mr.C! i demand to see some damage! :x
At 115psi...pfft. I doubt it'd do anything worth taking a picture over. :)
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elitesniper
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Fri Mar 07, 2008 8:24 pm

should do pretty good damge :P mabey on some, sheet metal or i dont know... plywood? :)
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MrCrowley
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Fri Mar 07, 2008 8:40 pm

Just got back from the first damage shots.

Managed to do 3 and a half (or 4, couldn't tell) soft drink cans at 105psi with a plastic 6mm BB. So i'm actually quite surprised at how powerful it is at such low pressures.
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elitesniper
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Fri Mar 07, 2008 8:53 pm

not bad not bad at all Mr.c but im not impressred yet comon dont do these baby pressure :) , i wana see some 200psi+
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MrCrowley
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Fri Mar 07, 2008 8:59 pm

elitesniper wrote:I wana see some 200psi+
That's what i'm <A HREF="http://www.spudfiles.com/forums/viewtop ... 96">trying to</a> achieve :)
Last edited by MrCrowley on Fri Mar 07, 2008 9:01 pm, edited 1 time in total.
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pizlo
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Fri Mar 07, 2008 9:00 pm

Nice job, my mini is a test for barrel sealers, and has the same rubber bumper/piston extender, and something to reduce pilot volume a bit, I'm gonna apoxy the rubber now, and then post some pics.
but yeah nice gun.
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Fri Mar 07, 2008 9:09 pm

Very nice but isnt the chamber a little overkill

Edit:never mind didint relise you mentioned it
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Fri Mar 07, 2008 10:23 pm

What did you use to get the barrel inside the chamber? Epoxy? some devious sleeving technique? or are there threads on the other side of the reducer...?
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MrCrowley
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Fri Mar 07, 2008 10:28 pm

To get the 6mm barrel inside the chamber, I drilled a hole in the end cap and JB-Welded it in.

But I think you're talking about the 20mm pipe I sleeved partway in the chamber, it just fit perfectly, though I did have to cut a groove for the seam (from the galvanised pipe) to run down.
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elitesniper
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Fri Mar 07, 2008 10:30 pm

hey Mr.C how do you drill perfectly in the middle of the end cap? , i always move to the side just a little bit every time i drill something like that.
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Fri Mar 07, 2008 11:01 pm

First coax? Find that a bit odd Mr Modd man... Anyway it looks as though you have outdone the allblacks and are on a winner!

What happened to your hybrid plans?
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Fri Mar 07, 2008 11:03 pm

elitesniper wrote:hey Mr.C how do you drill perfectly in the middle of the end cap? , i always move to the side just a little bit every time i drill something like that.
I didn't drill perfectly in the middle for this one. But I was pretty darn close. Just use a centre punch, like the thing DYI used to penetrate 1/4" steel.

It's like a huge nail, and you whack it with a hammer where you want to drill and it should leave a small indent, this gives the drill bit something to hold on to and should drill right at that spot.
Novacastrian wrote:First coax? Find that a bit odd Mr Modd man... Anyway it looks as though you have outdone the allblacks and are on a winner!

What happened to your hybrid plans?
Yeah, never really interested me that much as I had no high pressure source.
Haha I guess so :)

Oh and i'm still working on my hybrid, my brother has been using the car on weekends because of some stupid sailing thing, so as soon as I get a chance I can drive out to a plumbing merchant and pick the rest of the stuff up.

I still need an ignition source and barrel on top of the chamber and reducers. But i've got the meter finished. :)

Damn, just realised i'm working next weekend, then on Monday I leave for Sydney for the week to see Ozzy in concert.
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Fri Mar 07, 2008 11:15 pm

MrCrowley wrote: Damn, just realised i'm working next weekend, then on Monday I leave for Sydney for the week to see Ozzy in concert.
There are worse places to go than Sydney, not many, but there are some. :twisted:
And screw you too- ozzy will be a good trip bro! :x :shock: :?
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When you fill your car with refined oil remember that it has been paid for with blood and guts, some from your own countrymen, most not.
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