GTA
All Springer/NP/PCP Air Gun Discussion General => PCP/CO2/HPA Air Gun Gates "The Darkside" => Topic started by: nervoustrigger on August 25, 2014, 01:04:40 AM
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Shot count stinks but it rocks at checking and adjusting regulator pressure!
My old routine involved pumping up a 13ci tank which required 3 or 4 pumping sessions. Not only is that a bunch of work but with 20 or 30 minutes between sessions to let the pump cool down, it also took almost 2 hours to complete. Now it takes, oh, about 2 minutes 8)
It's just a piece of piece of 6061 aluminum bar stock bored out to 9/16" at 2" deep and with a countersink for the regulator's O-ring to seat into, then tapped to 5/8"-18. The neck needs some cleanup but I'll take care of that later. That it works is most important.
(https://www.gatewaytoairguns.org/GTA/MGalleryItem.php?id=5335)
(https://www.gatewaytoairguns.org/GTA/MGalleryItem.php?id=5336)
Here it is in action:
(https://www.gatewaytoairguns.org/GTA/MGalleryItem.php?id=5337)
Checking the output pressure of a standard Ninja regulator:
(https://www.gatewaytoairguns.org/GTA/MGalleryItem.php?id=5338)
I had been thinking about making one for a few weeks but this weekend I wanted to check the Ninja SHP regulator on Vigilandy's .22cal QB79 and I decided it was time to do it. I had initially adjusted the regulator to 1500psi and promptly had the 1.8k burst disk to rupture. So I replaced the burst disk and took it down to 1300psi for testing. This weekend I bumped it back up to 1500psi and...you guessed it, blew another burst disk. Hmm, I don't know what tolerances those things are supposed to have but it's apparently very loose. A 2k is going in next.
Before and after adjustment:
(https://www.gatewaytoairguns.org/GTA/MGalleryItem.php?id=5339)
(https://www.gatewaytoairguns.org/GTA/MGalleryItem.php?id=5340)
The good news is his rifle is shooting pretty hard for a 79. With the RVA adjusted to find the max velocity:
(https://www.gatewaytoairguns.org/GTA/MGalleryItem.php?id=5341)
(https://www.gatewaytoairguns.org/GTA/MGalleryItem.php?id=5342)
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Very cool, but the real questions are in the photos.
Tell us more about your filtration/ drying system.
And what chrono are you using?
Ian
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My old routine involved pumping up a 13ci tank which required 3 or 4 pumping sessions. Not only is that a bunch of work but with 20 or 30 minutes between sessions to let the pump cool down, it also took almost 2 hours to complete.
13 ci = 213 cc?
It shouldn't take that long to recharge.
You might need a different pump.
I pump my s510 (231 cc) in one go with my Hill pump. It barely gets warm. Only takes a few minutes.
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The filter & drier is an adaptation of tenring's design. I drafted a how-to which you can download here (https://www.dropbox.com/s/lcam2wbf7frl30y/air%20drier%20and%20filter.pdf?dl=0).
The chrono is a PS2 chronograph (http://www.catsdomain.com/chrono/). Very inexpensive...some folks have had issues but it works well for my purposes.
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Mike, yes on the 13ci = 213cc.
I'm talking about pumping from totally empty up to 2000psi. No doubt a Hill is better than a Benjamin pump but when you say you are doing it in one go, are you covering that much range?
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Mike, yes on the 13ci = 213cc.
I'm talking about pumping from totally empty up to 2000psi. No doubt a Hill is better than a Benjamin pump but when you say you are doing it in one go, are you covering that much range?
No, I stop shooting at 100-110 bar and refill to 200 bar. I don't have any reason to start pumping from zero. But 200 bar=2900 psi so I'm filling to considerably higher pressure.
BTW, why are you taking it all the way down to zero?
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I'm pulling out the regulator guts and adjusting it...
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I'm pulling out the regulator guts and adjusting it...
Guess he missed the part about adjusting the TANK regulator
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I'm pulling out the regulator guts and adjusting it...
You adjust the regulator every fill? :o
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I'm pulling out the regulator guts and adjusting it...
You adjust the regulator every fill? :o
Well.... Yeah. Don't you? ;D
Seriously though it sounds like Jason is had to adjust the SHP regulator from 1100psi to 1500psi to 1300psi back to 1500psi. At two hours per fill, this device will save a lot of time and backache! Once he has the regulator figured out he won't have to take it apart again.... I hope.
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If you have never tinkered with something trying to get it set just right, it involves a lot of taking it apart, adjust it, re assemble, test.
Then do it all over again until you get it where you want it.
Sometimes I thought my real job was taking apart and reassembling my air rifle.
I would be at work thinking,
ok, if it wasn't this, then it has to be this, then when you get home, it is in front of you until you go to bed, you get to where you can assemble it in your sleep.
And you get to know every part by a four letter word first name basis..
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I'm pulling out the regulator guts and adjusting it...
You adjust the regulator every fill? :o
I would have loved to have one of these this past week. I pumped and drained my 17ci bottle at least 10 times trying to "fine tune" my regulator to 1000psi, after I raised it from 600 to 800 to 900 to 1000 to 1100 to 1200 and then finally back to 1000.
I do have both a Benji and an Air Venturi G4 pump. If anyone is wondering my Benji seems to push more air at the low pressures and the G4 is smoother at higher pressures.
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If you have never tinkered with something trying to get it set just right, it involves a lot of taking it apart, adjust it, re assemble, test.
Then do it all over again until you get it where you want it.
Sometimes I thought my real job was taking apart and reassembling my air rifle.
I would be at work thinking,
ok, if it wasn't this, then it has to be this, then when you get home, it is in front of you until you go to bed, you get to where you can assemble it in your sleep.
And you get to know every part by a four letter word first name basis..
So I m not the only one.... ;D ;D
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cool idea
thanks for the links
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Where did you find a 2K burst disk ? I have searched everywhere. 3K is the next step from 1.8K. Thanks
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Rocko, it was scubaonline.com. I think they had it listed at 2015psi. I went ahead and ordered 2200 and 2400 while I was at it because the usual suspects jump from 1.8k all the way to 3k.
Too bad a 1.8k won't hold 1.5k pressure reliably. If they were bursting after taking the rifle from cool indoors to the hot outdoors, it would make sense but both popped on me inside the house. I also checked that the regulator was not creeping.
If you want to search around, it seems like "3/8" burst disk" is the term to use. The 3/8" refers to the size of the hex drive used to install it.
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Seriously though it sounds like Jason is had to adjust the SHP regulator from 1100psi to 1500psi to 1300psi back to 1500psi. At two hours per fill, this device will save a lot of time and backache! Once he has the regulator figured out he won't have to take it apart again.... I hope.
Hey, I'm all for using ingenuity to make things quicker and this sounds like a useful device for such troubleshooting/diagnosis.
But I'm baffled by the two hours to fill the standard reservoir, especially if it's only going from 0 psi to somewhere under 2000 psi on a reservoir that's only 213 cc. I fill my 231 cc reservoir over that same range in under 10 minutes. The real heat doesn't happen until I pump into the higher pressures.
If it takes two hours then a new pump or a pump re-build is probably in order.
That's all I was saying, nothing against the little special purpose tank that looks like a useful thing for such purposes. It can probably be pumped from zero in a minute or so.
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scubaonline.com. I think they had it listed at 2015psi. I went ahead and ordered 2200 and 2400 while I was at it
You will have to do some checking before you use those, because as I understand it, SCUBA burst discs are rated by the pressure of the tank they are intended to protect.... They are supposed to blow at the hydrostatic test pressure, which is 5/3rds of the pressure of the tank.... Therefore, a 2015 psi disc should blow at 3358 psi, etc.... In addition, not all burst discs are the same thread.... Please be careful, and don't just make assumptions....
EDIT: I cant find the website where I got that information, but many SCUBA websites state that SCUBA burst discs are designed to burst at about 40% over their rated pressure.... That would actually make a lot of sense, as the hydrotest pressure is 60% over.... If that 40% is true, a 2K disc would rupture at 2,800 psi, too high to offer proper protection, IMO.... Please be careful !!!
If you DO find a source of 3/8"-24 tpi burst discs that will fit our regulators properly of ratings other than 1.8K, 3K, 5K and 7.5K, PLEASE let us know as I have never found any (well sometimes you can get a 4.5K from England)....
Here is my version of a regulator testing tank.... Made from a piece of 1" CRS, drilled and tapped like yours....
(http://i378.photobucket.com/albums/oo221/rsterne/Discovery/FillStationandTestRig.jpg) (http://s378.photobucket.com/user/rsterne/media/Discovery/FillStationandTestRig.jpg.html)
Bob
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Jason, I am so tired of blowing the1.8k burst discs at 1400 lbs pressure that I just ordered some of the 2015 pressure discs you recommended.
I do think that the SCBA burst discs have about a 20% safety factor built into them. The 3000 lb discs seem to blow at about 3600 pound relief pressure. Have you tested the actual burst pressure on the 2015 discs with your arrangement?
This is a great post - I am going to the shop to build a similar test block for my use!
Roger
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hey Jason, ordered that mini chrony today .. told the seller he should look into getting on GTA and he said he would look into it ... looks like a nice little chrony to take with me ... I can compare it to the green chrony I now have
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Thanks for the heads up Bob. I'm not much on assumptions when it comes to safety so thanks for the information. I ordered spares so I can test by carrying it up to rupture pressure. I did not know about the 40% overage on SCUBA discs so it sounds like what I ordered will not give me the desired result. Of course if the threads are not compatible then all bets are off. Oh well, either way it's a $30 learning experience.
So frustrating that the 1.8k disks won't even let me get within 85% of rated, and come to find out other 3/8" discs are designed to sustain 140% of rated.
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My understanding is that paintball discs are supposed to be plus-minus 10% (or maybe only minus 10%), and I have certainly had some 1.8K let go at 1600, or at 1500 cold and then warmed up.... SCUBA tank discs, as I say, are apparently marked for the tank they are supposed to fit onto, and designed to rupture 40% higher than that, but 20% below the hydrotest pressure (which is 5/3res = 160% of MSWP).... The two systems of marking are different, it's not so much that one is under spec and the other over spec....
Bob
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If you have never tinkered with something trying to get it set just right, it involves a lot of taking it apart, adjust it, re assemble, test.
Then do it all over again until you get it where you want it.
Sometimes I thought my real job was taking apart and reassembling my air rifle.
I would be at work thinking,
ok, if it wasn't this, then it has to be this, then when you get home, it is in front of you until you go to bed, you get to where you can assemble it in your sleep.
And you get to know every part by a four letter word first name basis..
So I m not the only one.... ;D ;D
Nope - not even close -
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I received the burst disks from onlinescuba.com yesterday. They are indeed as Bob stated. For example, the one rated for 2400psi working pressure is imprinted with "4000" on the housing (a 5/3 ratio) so they are not suitable for my purposes. But it was immediately apparent that these were made differently; the diaphragms themselves are accessible and replaceable so I decided to test some common materials to failure to see if I could come up with something that will rupture around 2000psi.
The first candidate was a Coke can measuring 0.005" thick. I used a hollow punch to create a small disk from it and assembled it to the high pressure side of the regulator and began pumping. When the pressure climbed between 2000 and 2100psi, it ruptured. I then repeated the test and the second one ruptured between 2000 and 2100psi as well.
Very nice. I proceeded to replace the diaphragm and installed it on the regulated side of Andy's rifle and got it pumped up last night. I checked this morning and the gun is still charged. Neither of the 1.8k disks lasted more than a couple of hours so this is promising. I want to be sure it will hold up to a temperature-induced pressure rise so I plan to let it heat up outside today and see if it holds.
If anyone else attempts to make their own burst diaphragm, please be sure you understand what you are doing. High pressure air is very dangerous. I would not assume another soda can (even of the same brand) to have the same ultimate tensile strength. Definitely test to failure to confirm before you entrust your safety to it.
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Looking good. I placed the rifle in the sunshine for 1 hour to drive up the reservoir pressure. It was the hottest part of the day...no clouds, sun beating down hard. The metal parts were so hot that I did not want to hold them for more than about 3 seconds. The burst disk held up beautifully.
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Like you said, risky business, but better than using a 3K one, if you are confident in your testing.... It's not only the tensile strength of the can metal, though, but the diameter of the hole that would make a HUGE difference....
Bob
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It's not only the tensile strength of the can metal, though, but the diameter of the hole that would make a HUGE difference....
Right, thanks for the reminder. I meant to include that the aperture measured 0.153".
Also, for the sake of completeness I wanted to note I added a bleeder screw and an accompanying O-ring seat to the fill adapter. A better solution was offered by bigtinboat which in an adapter has a built-in automatic relief feature when you back off the hand screw. Only about $10 with shipping on ebay:
http://www.ebay.com/itm/CO2-FILL-ADAPTER-REMOTE-ON-OFF-DEGAS-WHEN-UNSCREW-AMERICAN-MADE-/271945664365?hash=item3f5139876d (http://www.ebay.com/itm/CO2-FILL-ADAPTER-REMOTE-ON-OFF-DEGAS-WHEN-UNSCREW-AMERICAN-MADE-/271945664365?hash=item3f5139876d)
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I have the same ASA with the built in bleed off and had to drill the knob to install a t handle to it to be able to rotate the knob to bleed off the pressure. at pressure over about 5oo psi it is had to turn and the threads will start to wear and deform even with extreme pressure lube on them. There is just to much pressure against the knob to allow it to rotate easily to bleed pressure.
Mike