unsafe gadget failure

Trophyhunter49 · September 24, 2015, 07:34:39 AM

I couldn't see any screws on the side of the gun either!! Also he said that he a couple of extions on it and their not made for HAP but CO2. This guy was asking for trouble from the word get-go!! I've looked into those unsafe gadgets and THATS just what they ARE !!!!!! If you will notice one of the extions was stuck in the sealing! The set up he had was for CO2! I'm glad he was not hurt real bad of he could have been killed or someone else in the room could have been !! Hads why you only use stuff thats made for HPA !! Ok , I'll get off my SOAPBOX now!

arkmaker † · September 24, 2015, 01:10:20 PM

One of the other things I have just read is that the wall thickness of the threaded section of where the two halves of the unsafe gadget screw together have gotten thinner since it's introduction. Old ones have been measured at around .065" wall thickness while newer ones have been measured at .025". These are not my measurements, but I really have no reason to doubt those individuals.

That, my friends is a very thin wall for HPA!!! Quality Assurance seems to be lacking. If this was a car maker, or for that matter a major gun maker like Crosman, would there be a re-call? It would be the responsible thing to do.

Trophyhunter49 · September 24, 2015, 04:26:22 PM

Quote from: arkmaker on September 24, 2015, 01:10:20 PM
One of the other things I have just read is that the wall thickness of the threaded section of where the two halves of the unsafe gadget screw together have gotten thinner since it's introduction. Old ones have been measured at around .065" wall thickness while newer ones have been measured at .025". These are not my measurements, but I really have no reason to doubt those individuals.

That, my friends is a very thin wall for HPA!!! Quality Assurance seems to be lacking. If this was a car maker, or for that matter a major gun maker like Crosman, would there be a re-call? It would be the responsible thing to do.

Not this guy !! He's all about the MONEY and not SAFETY !!!

arkmaker † · September 25, 2015, 01:13:28 AM

I feeling very generous today, so maybe his tube source sent him undersized tubes? or maybe he had to source from another company and they had different wall thickness? or maybe he actually knows the physical properties of the tube and concluded that a .025" wall was within the burst zone?

Like I said, I never saw the video, but have been reading about it a lot. I am no engineer, but .025" seems pretty thin. I think I will try to measure the wall on my disco next time I have it apart. It may be that thin as well for all I know, but I doubt it. Disco walls are the same as a 2240 tube wall right? So, if I find the major diameter of the cap thread and subtract it from the OD of the tube and divide by 2, that should give me the thinnest section of the tube, yes?

.8750 (Tube OD)
-.8125 (13/16-28 Major Diameter)
.0625 / 2 = .03125 (thinnest part of a 2300 smooth walled Co2 tube)

Even that seems thin to my, but it is only designed to hold back a Co2 cartridge, so yeah, ok, now what about material type? I think it matters much.

sorry for the ramble, my brain does this sometimes

BillK · September 25, 2015, 04:34:10 AM

Just measured a 1701P (3000psi) tube and it is .077.
Now, I am not precise nor am I a tool man. So the measurement is "good by golly".

Gippeto · September 25, 2015, 06:55:41 AM

Handy little tool for ya Rich;

https://www.engineersedge.com/calculators/pipe_bust_calc.htm

If you can't do the link, look up Barlows formula...for calculating hoop stress.

Wall thickness, diameter and material strength are major factors when determining hoop stress/burst pressure. I personally prefer to use yield strength of the material.

No tubing is used in the manufacture...the unit is machined from bar stock.

Al

onebaddj · September 25, 2015, 10:17:03 AM

Yeah stripping a gun full of air. Bush league right there. 2 what kind of hospital send you home with anasty hole in your leg like that the same night with paper towels taped to your leg.

And 3 all the work he was doing was on a stand, what was he doing that he had to have the gun on his thigh to get it apart. Ive worked on mine alot and never had to put it on my leg to get it apart. With the missing peice of video makes you wonder.

arkmaker † · September 25, 2015, 01:27:40 PM

Quote from: BillK on September 25, 2015, 04:34:10 AM
Just measured a 1701P (3000psi) tube and it is .077.
Now, I am not precise nor am I a tool man. So the measurement is "good by golly".

That's the ticket! I'm thinking that is not figuring in the threads major diameter? I think worst case when counting the wall thickness at the major diameter of the thread would put you at .050. That is an estimate using the 13/16-28 dimensions, but I don't know what thread they use on the 1701 tube. Then again, once the cap is threaded in, is there any loss of strength? Another variable to this whole thing is that some one said they had 3 of these and they all had different threads, course to fine?? That might make a difference? Lots of variables, to many for me to think about

I need to go to the library and watch the video!!

Also, if it is machined from a solid rod, then someone was not paying attention or the tolerance great on the bore and or OD. Or maybe there was a re-design to add more volume?? Yep, more variables..... but, I would be lying to you if I said I don't like thinking about these kind of things. My sick brain is Monday morning quarterbacking from the back seat of a pickup truck

1377x · September 25, 2015, 07:13:29 PM

I have no clue about the thickness of the tube but can say a disco tube i had filled at a paintball shop was filled to 4500psi or more. The gauge broke neither of us know it. The kid looked at the gauge it read 0. The kid realized the disco was overfull after he checked the compressor gauge. The tube did expand but didn't explode. I was told the threads are the weakest part of tube

AZAG · September 25, 2015, 09:14:06 PM

Quote from: 1377x on September 25, 2015, 07:13:29 PM
I have no clue about the thickness of the tube but can say a disco tube i had filled at a paintball shop was filled to 4500psi or more. The gauge broke neither of us know it. The kid looked at the gauge it read 0. The kid realized the disco was overfull after he checked the compressor gauge. The tube did expand but didn't explode. I was told the threads are the weakest part of tube

Makes sense for the threads to be the weak point in the tube. How were the valve screws after your 4500 psi adventure?

ped · September 25, 2015, 09:32:22 PM

disco tubes p-rod tubes and 22xx tubes are (afaik) all made from the same tube share the same filler cap thread and the tube has a burst pressure of 15000psi with the threads of the filler cap being the weakest link failing at 9000psi
the video has too many in accuracies and things that just won't work to my mind

1377x · September 25, 2015, 09:53:03 PM

The screws were ok some hss screws and that was recommended because i was using 2400psi. With 3000psi fills 10-32 hss screws are used.
After i read the failure thread and saw the video the guy is lucky to be alive imo so much more could have happened.

Gippeto · September 26, 2015, 02:59:05 AM

In a disco and 1701, the o-rings on the fill assembly are on the pressure side of the tube threads...threaded section is not subjected to hoop stress...only thread shear. IMO...this is a good design practice.

Al

Brutuz · October 28, 2015, 10:17:52 PM

[youtube]https://www.youtube.com/watch?v=ilM7gHYI0x8#]! read the comments on youtube too, click this link[/url]

Trophyhunter49 · October 29, 2015, 02:47:40 AM

After watching this video , the NUT DIDN"T have but ONE screw holding the valve in place!! Only ONE SCREW!!! He was asking for trouble by not pining the valve on each side!!