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Posted: Mon Jun 01, 2009 8:30 pm
by far_cry
VH_man wrote:starman wrote:Whew, you were precariously close to the edge of what looks like a homemade sandwiched plywood platform. Probably wasn't the safest shot of the year...result was impressive however.
actually, its an old rotting peice of wood. i have shot clean through it with this gun before....... so........ its actually QUITE safe. that and the cannon is.... like..... 4 feet long.
that and the camera was a good 20 feet away. it was just zoomed in.
as for penetration, im waiting for my bloody Mcmaster order to come in with the 0-600 psi guage so i can get my lead slug moving at speeds i want
. it was "out for delivery" at 2:45 thismorning and it still hasnt arived at 4:00 in the afternoon.......
i am sorry for kicking an old topic
but , did you get your gauge "11 month later"
Posted: Tue Jun 02, 2009 4:26 am
by rikukiakuchiki777
Sorry to be a noob, but how does the O-ring piston valve work? I've looked at the 'piston valves explained visually' but they all have equilisation holes and whatnot. If the O-ring seals the pilot area, how does the hpa get into the chamber?
Posted: Tue Jun 02, 2009 4:54 am
by jackssmirkingrevenge
rikukiakuchiki777 wrote:If the O-ring seals the pilot area, how does the hpa get into the chamber?
This is because the o-ring is "floating" at it only seals in one direction, a bit like these pump heads:
The grooves cut in front of the o-ring allow the air to flow one way ("down" if we're looking at the above photo) but behind the o-ring there's a solid unbroken steel washer that makes a perfect seal and therefore air cannot flow "up".
Posted: Tue Jun 02, 2009 4:59 am
by jmadden91
Mate that helps me a lot. I think i will have to make one of the above pictured pistons. My wooden one is not up to the job. Thanks JSR
Edit: Is the one used in the original gun floating though? It looks like a number of thin layers of rubber rather than an o ring (for the sealing face at least)
Posted: Tue Jun 02, 2009 5:55 am
by VH_man
far_cry:
Yes, Ill admit to it, I used my shock pump without a gauge. I went by how much the hose increased in diameter. Worked well enough... Seeing as the hose increases in diameter after a mere 200 PSI...
Posted: Tue Jun 02, 2009 10:38 am
by spot
Is the one used in the original gun floating though? It looks like a number of thin layers of rubber rather than an o ring (for the sealing face at least)
The O-ring on the piston is not floating. You can see that because the o-ring doesn't have any space to move. The thing you are talking abouth though is the sealing face. The right "rubber piece" is the o-ring, and the several rubber pieces to the left is the sealing face. If you don't know what a sealing face is, I suggest you to look it up in the wiki. (It's the part of the piston that seals against the barrel on a barrel sealing piston).
Posted: Tue Jun 02, 2009 8:16 pm
by jmadden91
I know what a sealing face is mate.
Where is the equalization on his piston then? Surely if that o ring is fixed the air couldn't get through? Unless there is just a hole or something not visible in the pic
Posted: Tue Jun 02, 2009 11:20 pm
by rikukiakuchiki777
jmadden91 wrote:
Where is the equalization on his piston then? Surely if that o ring is fixed the air couldn't get through? Unless there is just a hole or something not visible in the pic
My thoughts exactly. Is there an equilisation hole inside the piston?
Posted: Tue Jun 02, 2009 11:45 pm
by spot
Sorry, I was confused about you saying "It looks like a number of thin layers of rubber". I don't know wheree the equalization is, maybe the o-ring doesn't seal 100%? Because a hole or something would make the o-ring useless... And I doubt there's a check-valve hidden in the piston
Posted: Wed Jun 03, 2009 12:30 am
by jmadden91
yeh sorry mate i was talking about the sealing face originally. I was way off haha