This Is What Can Happen.....

[nervoustrigger]

Hats off to Randy for accepting the blame.... It's really a shame he missed the root cause of the failure, which was the single valve screw.

Agreed, very classy to accept responsibility.  And I'm pleasantly surprised after seeing the direction the Facebook exchange was headed.

However I thought he called attention to the sheared valve screw.  Or were you saying he missed that there should have been additional screws securing the valve?

The part I felt like was missed had to do with the sequence of events.  He said they don't know what failed first but it should be obvious that if the Hipac tube had separated first, that would have been most favorable in this particular instance because it quite literally would have saved his leg.  No tube = no pressure against the valve = no .75 cal hole in the thigh.  Instead, the tube would have rocketed away, pushing a blunt, more massive object into his leg, probably resulting in little more than a bruise.   

[rsterne]

Yes, he stated that the valve screw (singular) failed.... but he either doesn't realize he should be using three screws, or didn't mention that VERY important point.... necessary to prevent another similar failure in the future.... It's a good thing the Disco tube he is going to use "next time" has three screw holes.... Let's hope he uses them, and the light goes on as to what caused that hole in his leg....

EDIT: I just made a comment on his video, I hope he takes it to heart....
3rd EDIT: I see that my comment is only visible when I log in, even though I can see comments from others.... Is that normal for You-Tube?.... 

Bob

[chekbone]

chekbone; it is quite likely that you reassembled the washers in the wrong orientation. One of them is very difficult to get to fall in the right way around. If it's the wrong way the valve may still work as the washers prevent it from falling all the way in, but it will rattle when empty.

Nope, not a chance. I stack the washers on a pencil and bottom the pencil eraser onto the head of the check pin. They slide down the pencil and correctly into place every time.

I'd like to ask. Does JB-Weld create a chemical bonding reaction with the metal parts? Could it possibly be that that weakened the joint?

[chekbone]

EDIT: I just made a comment on his video, I hope he takes it to heart....
2nd EDIT: I see that my comment has been removed.... so I guess he just isn't interested in learning what happened.... 

Bob

Maybe he just wants to let it go.

[nervoustrigger]

Well, he surely wants to know why it happened.  If you ask a man if he would like to know why he has a 3/4" hole in his thigh, I'm rather certain his answer is an emphatic, "Why yes I do!".  And I think deep down, he knows and has known for some time.  But the pain, both physical and psychological, are too strong to bear seeing it in black and white.  It's a shame his accident won't serve as a vehicle to educate others on the root cause, so we'll have to use other venues like this one to educate people on safe practices.

[SpiralGroove]

Yeah,
Randy is just not ready yet to accept the facts of the situation yet, avoiding further humiliation.  My first question would be, where did the tube, broken off from the Hipac, end up?  Near the Hipac lodged in the ceiling or right next to him with the valve embedded in his leg?  IMO, the Hipac was snapped off, not blown off during it's trip to the ceiling.
However, he's done a great job of openly, not blaming the Hipac product or anyone besides himself.
If anyone watching that video is still not sufficiently compelled to avoid using only 1 valve screw, in addition to modifying the Hipac as Randy did, I'm sure Gilligan will have a lengthy conversation with them at the Pearly Gates (unless they go south).

[Gippeto]

I am greatly disturbed by Gerard's report that a HiPac, properly installed, was able to retain pressure in the tube with a normal 22XX valve and no added seal (except some grease) between the HiPac and the tube.... It makes no sense to me, as that is part of the safety supposedly designed into the HiPac system, that any leak in the seal would never be a problem, as the pressure would leak out past the valve and through the (unsealed) front threads before the pressure could even build up.... I had (and reading this, still have) concerns that the pressure would not necessarily bleed off quickly enough to prevent the single 6-40 valve screw used in a 22XX from shearing, but everyone reassures me this is not the case.... Yet here we have somebody stating otherwise.... It does make me wonder if I was correct in my initial feelings.... and very glad that Alex eventually recommended replacing that screw with an 8-32.... In Gerard's case, it would appear he was lucky he had three of them, or could have had a similar failure to that in this thread.... with the valve coming out the back of the gun.... The difference is, that in his case (and according to his retelling of it), he used the HiPac the way it was intended....

Bob

Whipped up an o-ring sealed plug for a 2240 tube this afternoon. Before drilling extra holes in my 2240 tube, I figured I would try and see if the threads sealed at 100psi off the air compressor. Secured the plug with a single 8-32 low head shcs.

Put your mind at ease Bob...the threads leaked like a seive. Isn't it nice how simple "machines" work in a predictable manor?

Neither the tube threads, nor IMNSHO, the story... hold air. I've no doubt Gerard had an "experience"...it's the claim that the tube threads sealed that I doubt.

About time to get ready for work...pictures tomorrow if there's interest.

Al

[rsterne]

Al, thanks for the report on how the 8-32 screw threads sealed, I'm not surprised.... If you are planning on testing how the HiPac threads seal into the Crosman tube, perhaps a test dry, and one lubricated with White Lithium Grease, if you have any, would be interesting?.... Does Alex recommend any lube on the HiPac threads, BTW?....

Bob

[Gippeto]

Bob...Hipac and 2240 tube were pressurized to 100psi....it was absolutely  out the tube threads. Did not use grease...will try that tomorrow, but expect the same result...grease does NOT seal against pressure.

Al

[rsterne]

Ahhhhhhh.... I misunderstood you.... it was the HiPac threads that were leaking like a sieve (dry).... I would imagine that the grease will simply extrude out of the threads (maybe quite forcefully) and then it will leak as before.... Nice when things work as intended, no?.... 

Bob

[Gerard]

Well doubt all you like based on your experiment and experience, but the fact remains the front end of my 2240 tube was pressurized. When at last I was able to unscrew the last bit of the HiPAC thread there was a tremendously loud and powerful blast of air as 2,200psi came out the front of the tube all at once. I had good shop hearing protection on, but wished I'd also been wearing my Etymotics as the blast still hurt my ears. The rubbed-on aluminum left on the HiPAC from the vise soft jaws took a bit of scrubbing to get off, and clearly showed about 1/2" of movement of the HiPAC in the very firmly (being careful not to damage the tube) tightened vise. If you're suggesting by this that some magic was involved, well, I'll leave that to 'true believers' but my experience demonstrated that indeed the threads held air. You can poke all the fun you like, it doesn't change the fact that it happened.

Perhaps my threads and your threads are not an exact match? Why would they be? Even two sets of threads cut by the same machine are rarely identical, same goes for the tube dimension and contact at the end of the threads. I haven't had the HiPAC off since installing the Lane regulator, but as I recall the fit to the Crosman tube's threads is slightly more snug than with the Crosman front plug. A good fit in this case.

And no, grease doesn't in itself hold pressure. But it does facilitate a tighter turning of threaded components given the same torque, does it not? When I worked with high performance bicycles back in the early to mid-1980's we always used a film of Campagnolo white lithium grease on critical components' threads as a means of ensuring the parts were well tightened without risk of damage to the threads by jamming. Few threads are perfect. The right grease makes a lot of difference in getting past the imperfections and getting things tight enough to stay tight in hard use, while avoiding stripping threads or rounding over bolt heads (or skinning knuckles) through excessive effort. In most cases a bolt will thread in a few degrees further with a good lithium grease evenly applied. It certainly made a difference in assembling the extension tube of my HiPAC, which without grease but with the same level of polishing was still slowly leaking. In that case I used a heavier hydraulic grease as I had no intention of disassembling the extension tube, so less need for the lithium's flowing characteristics.

[Gippeto]

Yep...even with grease the threads leaked. Grease did slow the leak slightly but no where near stopped... I'm only using 100psi.

Gerard, I suspect that much like the two fellows whom this thread is about, you had an experience that you don't understand, and are blaming what you honestly see as the culprit. After stating it as many times as you have, you've got it ingrained into your head that "this" is what happened, and are closed to exploring other possibilities.

Just like the two fellows who figure the hipac separated first...and somehow caused the valve to depart. Of course...no one tolerated the idea long enough for it to take....

Simple machines act in predictable manors...the 2240 with hipac is a VERY simple machine.

Al

[Gerard]

Yep...even with grease the threads leaked. Grease did slow the leak slightly but no where near stopped... I'm only using 100psi.

... and you don't see the problem with your experiment not even remotely testing to confirm nor refute (magically, since it happened) my experience? The 2,200psi was introduced to the front threads when the valve face seal blew to bits at that pressure, dumping the pressure into the thin gap between main tube and HiPAC narrow end. That kind of pressure slamming into about 10 turns of fairly fine thread full of grease might just behave differently. Many's the time I struggled to get my HiPAC to even fill up from zero, as the simple valve at the Foster fitting wouldn't hold air until getting well over 100psi. Same with the various delrin seals I made for the valve poppet after blowing the stock Crosman seal, which can't handle that much pressure. If not perfectly fitted a harder plastic seal seems to prefer the fast dump of pressure from a tank, something I don't have, at least until the seal plastic is broken in. And yes Al, I have made several conical delrin seals... for my latest project, a QB78. So far they've all leaked, no matter how well I polish and clean the brass and how well I made the cone to that brass. Finally settled on a shaped delrin poppet seal like I settled on for the 2240, and hey, guess what, no leaks! Putting 100psi into a tube proves zero in terms of replicating what the HiPAC did in that airgun.

Gerard, I suspect that much like the two fellows whom this thread is about, you had an experience that you don't understand, and are blaming what you honestly see as the culprit. After stating it as many times as you have, you've got it ingrained into your head that "this" is what happened, and are closed to exploring other possibilities.

Such as? As I've several times stated in this thread and on CAF, I'm open to suggestions. And while you may not see it as such, I'm a bit taken aback at being compared to a guy who has "built hundreds of these things" as the guy in the video stated, for "three years", and still doesn't have the slightest interest in properly securing a valve in a tube. Sure I can be an idiot at times, so can we all, but I'm not quite that big an idiot.

If you somehow, again probably invoking magic, replicate my EXACT HiPAC and 2240 tube's threads and put 2,200psi into the situation with one of those nasty, gummy little black seals Alex supplies with the thing, whatever material that is (a softer form of kydex maybe?) installed for a seal, then perhaps you'll get close to matching my results. Don't know. I can't supply you with torque figures or other exact specifications, and in spite of what you say about it being a simple machine, what happened seemed anything but simple.

[rsterne]

I learned a long time ago that in theory, there is no difference between theory and practice.... but in practice there is....

While Al's testing, and all the logic in the World, point to the fact that parallel threads can't hold air (there is, after all, a helical path between the threads from end to end), nor can a 22XX valve which is several thou smaller than a 22XX tube seal into it without an O-ring (or similar).... I suppose that there is a small chance that something strange happened in Gerard's case.... There are other possibilities as well, so we are left with a story that conflicts with logic.... In physics, there is a very small probability that all the molecules in a book laying on a table will all move in the same direction at the same time, sending the book accelerating through the ceiling.... but I wouldn't want to wager on it happening during my lifetime.... On the other hand, I would never say it is impossible, either.... just highly unlikely....

Just as we can't duplicate Gerard's experience, we also can't go back in time to figure out what happened to the HiPac that Randy had blow up during the incident that inserted a Disco valve in his leg.... Unfortunately, we will likely never know exactly what happened in either case.... That really has nothing to do with the fact that the Disco valve only had one screw, and it failed, causing serious injury.... We need to focus on that and spread the word so it never happens again.... I had hoped that by making a comment on his recent video that would help spread that word.... and I am saddened that he chose to remove that comment for reasons only he knows....

Bob

[Gerard]

Probably bruised ego. That's a string motivator for such an action in a case like this. A secondary motive could be fear of the consequences, with whatever number of his airgunning customers who have his one-screw-secured valves very near to their faces on a regular basis potentially becoming somewhat concerned as they follow this unfolding development. As Al said, once you have a running story it can be hard to shift tracks. In this guy's case he's done something reckless, paid a price, published the video along with rash claims, and now backpedaled and sort of apologized, while not really taking responsibility for the central mistake. In my case I'm not only open to suggestions, I'm positively eager for suggestions which might better explain what happened in a rather disturbing and seemingly impossible circumstance. I'm not militating against any other possibility in the way he is, not claiming Alex is responsible for the sealing of my valve against my tube however that happened. I'm just curious.

And yes, I do hope that this discussion leads to some better-considered actions among would-be modifiers of a number of airgun models. And I think it shall. All this chatter is searchable via any search engine and most of it will remain so for many years. That's got to be helpful.

[SpiralGroove]

I learned a long time ago that in theory, there is no difference between theory and practice.... but in practice there is....

Hallelujah

[chekbone]

A few things my dad told me growing up, and I quote. "Learn everything you can about what you want to learn". "Be smarter about life today than you were the day before". "The best way to avoid s--t is to avoid S--t". And lastly, "Anything's possible when people make up their own story".

[oil dripper]

While Al's testing, and all the logic in the World, point to the fact that parallel threads can't hold air (there is, after all, a helical path between the threads from end to end)

Here's a theory, what if a piece of debris got caught in the threads/grease and sealed off that helical path?
Might explain why it was hard to unscrew the  tube at the beginning?

[Gerard]

While that might be possible, in my case debris was not present. I am always very careful and thorough about making everything absolutely clean on assembly. Thanks for the idea though.

[rsterne]

Not a bad thought.... when you applied the grease, it could have had a piece of dirt/grit in it that clogged the helical path along the threads.... just a suggestion, if you are looking for explanations....

Bob