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| Jack_Hogg |
 Posted: 10/15/2009 0:16 AM Post subject: Almost done! |
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Sergeant First Class
Joined: 20 Feb 2007
Posts: 132
81.07 Spud Bux
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I am making a pneumatic airgun for firing marbles. I am busy the last weeks on some things, so I don't have much time to work on my gun.
I am totally new to pneumatic spudguns. Then also this will be my first one  Well, that in mind, I want it to make it preform as good as
it gets. I have made some pictures with my phone, (sony ericsson C510) below:
The gun.
Sealing face.
Pilot.
Piston installed.
How it looks when it seals against the sealing face inside the gun.
Piston.
Another angle.
Another angle.
Trigger, little blurry 
The 10mm metal bracket. (Made with a laser cutter)
Bracket fixed.
And the ¾'' BSP outside threaded pipe I found on highschool. Used for connecting the T-peices and the endcap. (for make it more compact)
Last edited by Jack_Hogg on 03/07/2010 13:09 PM; edited 3 times in total |
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| psycix |
| Posted: 10/15/2009 3:11 AM Post subject: |
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Donating Member
Joined: 25 Jun 2007
Posts: 3701
17.61 Spud Bux
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That looks good! Its shiny, did you polish it?
Your trigger is very BTB, I've got one just like that (from him).
Why is there a T instead of an elbow below the valve?
I think the barrel support and the piston could be made much lighter, I suggest to improve that to complete a very well built gun.
Keep up the good work!  |
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| VH_man |
| Posted: 10/15/2009 4:31 AM Post subject: |
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Swimmaman
Joined: 09 Dec 2006
Posts: 1846
168.46 Spud Bux
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My only complaint is that the hollowed out portion of your piston is increasing pilot volume. Fill the hole in with something light but airtight, Like a mix of cheerios (or Styrofoam if you must use legitimate building materials) and epoxy.
also, whats that hole in the side of the piston for? It seems to me that it's decreasing your power immensely. It looks as if its an Equalization hole, which is unnecessary if you dont have O-rings sealing the piston.
Finally, After constructive criticism.... Very nice gun. It looks very clean and professional, and i'm sure will be amazingly fun at the higher pressure ranges. That and I envy your machining abilities. Ive always wanted to make a piston valve as gorgeous as this... |
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| tghhs |
| Posted: 10/15/2009 5:01 AM Post subject: |
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Sergeant Major
Joined: 31 Dec 2008
Posts: 180
424.88 Spud Bux
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| WOW! thats sweet man, yeah awesome machining work, is the piston steel? It's been said, just try and lighten it as much as possible. |
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| Jack_Hogg |
| Posted: 10/15/2009 5:34 AM Post subject: |
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Sergeant First Class
Joined: 20 Feb 2007
Posts: 132
81.07 Spud Bux
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| VH_man wrote: | | also, whats that hole in the side of the piston for? It seems to me that it's decreasing your power immensely. It looks as if its an Equalization hole, which is unnecessary if you dont have O-rings sealing the piston... |
I have just tested the piston today, and it preforms.., well... kinda slow..  I think I have to fill up the hole.. but my next question is, will air, flow around the piston quickly enough to fill up the air chamber?
| Quote: | | also, whats that hole in the side of the piston for? It seems to me that it's decreasing your power immensely. It looks as if its an Equalization hole, which is unnecessary if you dont have O-rings sealing the piston. |
I will fill up the hole with some epoxy i think... U are right about decreasing power immensely. Thanks for the tip.
| tghhs wrote: | | WOW! thats sweet man, yeah awesome machining work, is the piston steel? It's been said, just try and lighten it as much as possible. |
Thanks mate  The piston is made of aluminium.
| psycix wrote: | | Why is there a T instead of an elbow below the valve |
Just for the looks:) |
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| auxiliary |
| Posted: 10/15/2009 7:50 AM Post subject: |
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Sergeant
Joined: 20 Jan 2008
Posts: 88
337.11 Spud Bux
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| The piston will allow enough airflow for filling without the hole as long as it isn't extremely tight in the housing like hydraulic tube. |
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| jmadden91 |
| Posted: 10/15/2009 8:52 AM Post subject: |
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2nd Lieutenant
Joined: 07 May 2009
Posts: 247
204.09 Spud Bux
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Wow mate it is absolutely gorgeous congratulations.
One reason the piston may be underperforming is the way the pilot is being vented through the male quick connect, it looks like it may be choking the flow a bit perhaps?
Congrats again mate  |
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| Mitchza89 |
| Posted: 10/15/2009 9:08 AM Post subject: |
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Brigadier General
Joined: 08 Jan 2007
Posts: 1058
2260.67 Spud Bux
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That's one of the best looking guns I've seen for a while. Fantastic work there mate. As far as performance goes.... Your piston looks beautifully machined but the equalization hole is way too big. The reason your performance isn't too good is because of the combination of that hole and the compressor quick connect. The ball valve is more then big enough to pilot the gun but that quick connect is constricting how fast it can pilot. It doesn't help that the equalization hole is nearly the same size. All the pressurized air is going out straight out that hole and through the quick connect fitting.
Keep up the great work and I hope everyone's information helps you
EDIT.... I should have read what you said first Mr Madden
Nice to see we're on the same page though hehe |
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| Jack_Hogg |
| Posted: 10/15/2009 9:47 AM Post subject: |
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Sergeant First Class
Joined: 20 Feb 2007
Posts: 132
81.07 Spud Bux
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Ok thanks for nice comments So, how should I add a quick connect without the male side? Or perhaps a bigger male quick connect? (those short thick male connects) Maybe that will fix the problem? (including the fact that I will fill up the piston with some hot glue) 
And if all those problems are fixed, including the fact that I still need an fridgecompressor (getting one soon for free), well then I think I am going to solder brass iron sights (rear sight on the T-piece, and front sight offcourse on the barrel itself). And I am thinking of adding a good grip, like cordwrapping the handle or perhaps a rubber heatshrink. Also, the ballvalve is a bit stiff, how do I get the ballvalve looser? (piloting smoother) Thanks for the help people  |
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| psycix |
| Posted: 10/15/2009 11:37 AM Post subject: |
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Donating Member
Joined: 25 Jun 2007
Posts: 3701
17.61 Spud Bux
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| Quote: | | how do I get the ballvalve looser |
That's how ball valves are. Its because of the seal.
Some oiling helps a bit, and chucking the rod into a drill, spinning the hell out of it may also loosen it somewhat. It may help a bit, but a ballvalve will always be stiff.
I don't think the male quick connect is much of a problem. The heavy piston in combination with the hole is. |
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| Brian the brain |
| Posted: 10/15/2009 15:12 PM Post subject: |
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Dutch Spud Clan Leader
Joined: 05 Dec 2005
Posts: 2763
6458.86 Spud Bux
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| Quote: | | One reason the piston may be underperforming is the way the pilot is being vented through the male quick connect, it looks like it may be choking the flow a bit |
NOOO!!
works fine!
So does Psy's
And even with an empty schrader:
No problem piloting.
The problem is blowby and piston weight.Also, a gun like Jack's should be fired at pressures over 300 PSI..
Anyone for calling this type of design a Dutchy?
I made several, Psycix has one, TNW has one and now another Dutch spudder.
I have to say this one is the prettiest "copy" so far.
I love the stacked Tees..I only did that on my first version , also for looks, and I must say...it rocks!
I love the trigger, very well done!
If I hadn't made mark III ( TOP PICTURE) recently I'd be pretty pissed
Almost got beaten at my own game..
It is most similar to my first one but way better..
You might want to try a 28 mm copper barrel and some big 1" marbles ( bonken)..you will be amazed... |
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| Mitchza89 |
| Posted: 10/15/2009 18:19 PM Post subject: |
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Brigadier General
Joined: 08 Jan 2007
Posts: 1058
2260.67 Spud Bux
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Dutchy sounds good. Funny though, I've made many many guns that have that exact design and my mums side is dutch
Ironic.. |
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| Jack_Hogg |
| Posted: 10/16/2009 3:01 AM Post subject: |
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Sergeant First Class
Joined: 20 Feb 2007
Posts: 132
81.07 Spud Bux
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Ok, psycix. So can you make a drawing (scetch) how I should make the piston? That would be great, only today, becouse tomorrow it's a week off so I don't have a lathe.. you nkow..  |
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| Crna Legija |
| Posted: 10/16/2009 3:41 AM Post subject: |
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shots shots shots
Joined: 20 Jul 2008
Posts: 1912
1660.53 Spud Bux
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| Don't fill the hole piston with hot glue, is better to fill it with a light foam and hold it in with epoxy. it will keep it light and still have lower pilot.if you make a new piston try UHMW,teflon,Nylon or delrin to make it even lighter |
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| Jack_Hogg |
| Posted: 10/16/2009 8:53 AM Post subject: |
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Sergeant First Class
Joined: 20 Feb 2007
Posts: 132
81.07 Spud Bux
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Well, too late, I already have changed the piston now, and preformance is a little bit better, but not how I like it, well the results are
1. Testing with first version was like psssssstPOW
2. Testing second version was like pssstPOW
3. Testing 3rd version was like psstPOW
4. Testing 3rd version with lube was like psssssssssstPOW
All tests were at 180PSI
So I was using model steam engine oil as lubricant. If I don't use lube on the 3rd version, I have best preformance but not good enough.. The second version was just like the first version but with the rod screwed in.
So here it is:
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