GTA
All Springer/NP/PCP Air Gun Discussion General => Machine Shop Talk & AG Parts Machining => Topic started by: rsterne on September 02, 2012, 03:08:26 PM
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Here is a photo (from the Green Forum) of a gauge fitting soldered to the side of a Benji 39X pumper tube with soft solder....
(http://i1048.photobucket.com/albums/s375/chaldeman1984/e4a8c29a.jpg)
I think this is a ridiculously dangerous practice.... If the joint is perfect, maybe.... but IMO too many variables....
Bob
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Whoa, that is an accident waiting to happen. If done perfectly by a professional with silver solder it would be just scary. That looks like a hack job done with a Bic lighter and coat hanger.
An o-ringed valve body similar to a Discovery would work if there were clearance but any kind of blemish on the tube and then heat treatment / annealing is not a great idea.
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I would be OK with it as long as the air hole was tiny. Even if the solder let go the air would leak out slowly. So no catastrophic event in case of failure.
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VERY VERY Dangerous and one other thing to consider is drilling a hole in the tube and heating that area to solder the nut in place can and will cause the barrel to be pulled to that side. Now you end up with a barrel that could explode at and time and one made to shoot around corners
Norm
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I.E.D. waiting to happen :o.
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as long as the air hole was tiny. Even if the solder let go the air would leak out slowly. So no catastrophic event in case of failure.
That's assuming there isn't enough volume of air at 1500 (or whatever) psi between the (small hole in the) tube and the gauge to launch the gauge into your (insert body part here).... It's not the escaping air that is the problem, it's how quickly the gauge/fitting assembly comes flying off the gun with a force of 165 lbs (or more) behind it....
Bob
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as long as the air hole was tiny. Even if the solder let go the air would leak out slowly. So no catastrophic event in case of failure.
That's assuming there isn't enough volume of air at 1500 (or whatever) psi between the (small hole in the) tube and the gauge to launch the gauge into your (insert body part here).... It's not the escaping air that is the problem, it's how quickly the gauge/fitting assembly comes flying off the gun with a force of 165 lbs (or more) behind it....
Bob
That could be a problem. But probably only about .01 or .02 cubic inches of volume. Maybe a 1fpe explosion. It could cause a bruise.
I still feel the same. If the hole was tiny, no big deal.
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I hadn't thought of it that way, but I guess you're right.... If the volume is only 0.01 CI, and at 1500 psi the maximum energy from isothermal expansion is only about 5.8 FPE/CI = 0.06 FPE.... A 1 oz. gauge would only reach 8 fps....
So as shown, it's very dangerous.... With a 0.010" hole in an otherwise continuous tube wall it's not an issue.... Live and learn....
Bob
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:(
How many forums did you feel it necessary to start this thread on Bob...that's four I've counted thus far. Curious as to why you started it on other forums at all if I'm being honest.
Poor guy has been trashed everywhere you started the thread...IMNSHO, you're responsible for it...and you owe him more than an admission...you owe the man an apology, and just as publicly as he was trashed.
This is called having integrity where I come from.
Used to think you were a good guy Bob...now I'm having doubts.
Al
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:(
How many forums did you feel it necessary to start this thread on Bob...that's four I've counted thus far. Curious as to why you started it on other forums at all if I'm being honest.
Poor guy has been trashed everywhere you started the thread...IMNSHO, you're responsible for it...and you owe him more than an admission...you owe the man an apology, and just as publicly as he was trashed.
This is called having integrity where I come from.
Used to think you were a good guy Bob...now I'm having doubts.
Al
Interesting bit of drama .... Huh ?
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Well, Al, I thought it was a safety issue, and I thought at the time it was important to discuss it on the four Forums I visit.... As you are aware, I usually post the same threads on all four.... I'm glad I did, because it was pointed out to me that with a pinhole feeding the relatively small volume under the gauge it wasn't.... If I hadn't brought this to the attention of other (more knowledgeable) people, I would have gone on believing it to be a poor practice.... The guy didn't help much by posting photos of versions that he didn't use.... Walter finally made a suggestion that DID make a lot of sense, and I have endorsed it, as I'm sure you have seen....
You're right, his final version appears to be safe, and I'll make that clear on all the forums....
Bob
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An Apology to Casey on the Green Forum....
I felt very strongly that the soft soldering of a gauge fitting on the outside of a Benji tube was unsafe.... Rather than simply discussing it on the Green Forum, however, I started threads about it on four other airgun forums entitled "Safe or Silly", and while it was not my intention to ridicule Casey, but to question the method, the result was I generated criticism of him, as well as better information and other ways of viewing the safety of the installation.... Once I learned that Casey restricted the flow with a pinhole, it was pointed out to me that the captured volume was small enough to not be dangerous, and I have agreed with that on this and the other Forums.... However, I had no right to take this further than the Green Forum, regardless of what my intentions were, and for that I apologize....
Bob
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Bob,
Sometimes the actions we carry out have a negative impact upon others...it's at these times that we find out which values we TRULY have...what kind of man we ARE...not merely THINK we are.
Despite having to be prodded and attempting to justify yourself, you stepped up Bob...in today's world of "I'm not responsible for what I do because...." I find that this quality is becoming increasingly rare...I still maintain a high value for that quality in people. In particular of the people I choose to associate with in some way.
I won't thank you for doing what was right...but I will state that I appreciate you doing so.
Al
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Without the knowledge of the other forum posters the end result would not have came to light. I see no problem with the way you handled the situation. You never named him you simply stated why you thought it was a bad idea and asked for insight from other points of view. In my opinion you are a very respectable man. I apprecite all you bring to this forum. And for that I thank you sir.
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Al, you were right to take me to task, and I'm embarassed that it was necessary.... I should have kept the discussion on the Green, although I would likely not have had the benefit of other points of view, educating me about how a pinhole (which I found out later was used) would reduce the risk.... The ultimate result, of Walter's suggestion of using a pipe cap profiled to the tube, soldered on, and then a small hole drilled through both, is so simple and effective, I should have thought of it (but didn't).... Once again, I probably wouldn't have learned that, had I not taken this to the other Forums.... Walter's solution is SO effective, you could glue the pipe cap onto the side of the tube with JB Weld (3500 psi) and not have to worry, providing the connecting hole is small enough.... The REALLY embarassing thing is that Casey used the profiled pipe plug and small hole in his final version.... So I learned two important lessons by this fiasco....
1. I still have a lot to learn....
2. I need to learn to keep my mouth shut....
These can be summed up as "listen more, talk less".... Thanks again, Al.... and I'm sorry it was necessary....
Bob
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Bob, a picture of what not to do can be a thousand times more informative than one of the job done correctly. There is a lot urging of folks to do their own work on these forums by well intentioned members not realizing that everyone has different skill sets, experiences and aptitudes.
Posting on this forum was constructive, invaluable and well intentioned IMO. Many of us do not spend a lot of time on the other forums and would not have seen the post at all.
And shame on those who would flame the guy instead of offering constructive assistance.
Tom
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Well Bob
I'm going to chime in with Tom here. I think you were correct in bringing forward your objections to the practice. If someone read that post and tried that on an HPA tube for example. And for discussion the joint wasn't perfect leaving an area under the fitting that wasn't fused you could be looking at a force of 600lbs being exerted against solder....regardless of the size of hole. Add that to embrittlement possibilities or altering the heat treatment of the parent metal and it is feasible that a catastrophic failure could occur.
In short advising people not to heat pressure vessels is prudent advice unless you have specific knowledge of what your doing.
And yes shame on the people who are all to eager to flame someone with nothing constructive to offer
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I never would have seen this (still haven't seen the other threads) had it not been posted here. I do not visit the other forums much.
I learned something. I see nothing wrong with seeking other opinions when I have questions about something. I really don't care if someone got there feelings hurt on the internet. I'm always tinkering with something and have no issue if someone wants to question or warn me of any issues, especially safety implications they see arising.
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I never would have seen this (still haven't seen the other threads) had it not been posted here. I do not visit the other forums much.
I learned something. I see nothing wrong with seeking other opinions when I have questions about something. I really don't care if someone got there feelings hurt on the internet. I'm always tinkering with something and have no issue if someone wants to question or warn me of any issues, especially safety implications they see arising.
Yes, when you post on the internet you are exposing your underbelly and should understand what can happen. I haven't seen the other posts either but the word is there was an unnecessary lack of civility and not on Bob's part. Although he could have picked a better adjective than "ridiculously". LOL.
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solder and high pressure is a big NO
Cheers marno
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I hadn't thought of it that way, but I guess you're right.... If the volume is only 0.01 CI, and at 1500 psi the maximum energy from isothermal expansion is only about 5.8 FPE/CI = 0.06 FPE.... A 1 oz. gauge would only reach 8 fps....
So as shown, it's very dangerous.... With a 0.010" hole in an otherwise continuous tube wall it's not an issue.... Live and learn....
Bob
Still wouldn't want 1oz @ 8fps in my eye while seeing how much psi was in the gun...
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i'm a lot more interested in what happen when the tube splits from fatigue at that hole
than I am in what happens if the threaded port pops off.
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solder and high pressure is a big NO
Cheers marno
I would qualify that to "solder improperly used". When used properly in keeping with a good design it seems to hold together with two pressure vessels at 10,000 psi or so, both pressurized in quick succession :-). Do not want to violate forum policy so you will have to think on that one to discern the projectile launching device I speak of :-). Barrel liners are often just GLUED in with acraglass and experience 24,000 psi or more, the key thing is enough sq inches of bond or solder to do the job....or they are soft soldered in.
Bill
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in the pic I see what very much look to me to be soft solder, doesn't really even look like Lead Free high/tin from lowes
that has a light colored brighter shine even when aged
and i'm about as sure as I can get from a Pic that it's not bearing (hard) solder..the soldering itself doesn't appear to have been properly fluxed
in the pic the tube appears to badly (from a structural viewpoint) prepared, lots of possible stress risers and a reduction
of material thickness leading to a place of material removal, soft solder doesn't add much by way a strength to make
up for the removed material.
for certain, that is not a silver solder joint, the appearance would be much more like a brazing as the temp required to
flow silver solder are up there with the brass compared to the low heat requirement of soft solder.
my question is still how big of a bang would that tube make if it burst?
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my question is still how big of a bang would that tube make if it burst?
Yes, a very real concern my friend.
Precisely what material is that tube made from, anyone know?
Pinhole port aside, what you have in that picture is a pressure vessel with a very large heat affected zone surrounding that fitting.
I don't think that the fitting flying off is the immediate problem, I think that the heat affected area has the potential to fail as a whole, and separate from the tube body in an abrupt fashion.
What are the chances of that tube being an air hardening alloy? Anyone care to guess what the compositional and structural changes are between the heat affected zone of that modification and the parent tube body?
At pressure, that tube will expand and contract at vastly different rates due to the compositional change in the steel at that site, leading to accelerated fatigue, and failure. Add to that the affects of vibrational feedback from the shot cycle, and it has even more potential to fail.
Without knowing the composition of the tube material and how it will be affected by heat, even heat as low as 250 to 400 degrees Fahrenheit, I would make a SWAG of 'not for me'.
Of course, I may be all wet, and completely off base. Please feel free to correct me as applicable.
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my question is still how big of a bang would that tube make if it burst?
Yes, a very real concern my friend.
Precisely what material is that tube made from, anyone know?
Pinhole port aside, what you have in that picture is a pressure vessel with a very large heat affected zone surrounding that fitting.
I don't think that the fitting flying off is the immediate problem, I think that the heat affected area has the potential to fail as a whole, and separate from the tube body in an abrupt fashion.
What are the chances of that tube being an air hardening alloy? Anyone care to guess what the compositional and structural changes are between the heat affected zone of that modification and the parent tube body?
At pressure, that tube will expand and contract at vastly different rates due to the compositional change in the steel at that site, leading to accelerated fatigue, and failure. Add to that the affects of vibrational feedback from the shot cycle, and it has even more potential to fail.
Without knowing the composition of the tube material and how it will be affected by heat, even heat as low as 250 to 400 degrees Fahrenheit, I would make a SWAG of 'not for me'.
Of course, I may be all wet, and completely off base. Please feel free to correct me as applicable.
I have never heard of an air hardening alloy being sold as tubing (but I learn new things every day). Somebody was kind enough to send me a spreadsheet on tubing strength when used as a pressure vessel...the 4130 tube that gets used for a lot of stuff is "normalized" so it is not getting it's strength from heat treatment.
But the "heat affected zone" is an area where the surrounding metal quenched the heat, so it actually may be harder, even if it is not an air hardening alloy, BUT I think the metal needs to be heated to above the critical temperature, which would be "red hot" ? If you stay below the critical temperature all you can do is anneal or soften the metal ?? And it if were "normalized" . Lots and lots of race cars are built from normalized 4130 tubing TIG welded together, works out very nicely.
Bill
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the picture has been taken down...but I looked it over 3 times and it appeared to me to be brass.
I think the AG is a benji pumper....I generally use my right hand to cock my break barrel so I would
also use my right hand on a multi pump so that damaged area would be pointing at my face during
pumping...
as somebody who has blown up a lot things via the whoops process, i'm calling this a Bad Plan.
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There is tubing available in air hardening alloys, but whether or not it was used by Benjamin is debatable, and in all actuality probably really remote.
My main point in using that as an example was more of a what if scenario.
I have destroyed many items in the name of modification, and escaped serious injury a few times. Due to that, I always err on the side of caution, and assume worse case scenario.
It may turn out to be a proven mod through repeated use, but I don't really want to be the guinea pig if you know what I'm saying!! ;)
I wish him lots of luck with the mod, and hopefully it gives good accurate service.
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The real part of what I see here is that people should be encouraged to actually have items tested to ensure safety.
The speculation of many does not even begin to outweigh a proper hydro test which would cost about 60$.
There is a company called Galiso that is in my hometown of Montrose, CO that makes the hydro testing rigs that are used worldwide. There is a guy that works there named Rick. He was extremely gracious and helpful to me when I machined my air tubes. They charged me 60$ to perform a DOT standard test on my stuff, and it came with a printout and his interpretation of the results.
My tanks had odd threads, so I had to machine an adapter for their machine......that was it.
My tanks passed the DOT test easily for a working pressure of 3000psi, but I learned from a post that I had made about them that many contentious people still doubted their safety based solely on the dimensions of the cylinders. If I had relied on the opinions of folks that were certain that they knew "what was safe, and what wasn't".......I would have thrown away perfectly good cylinders and started over.
All the doubt and speculation in the world does not amount to a hill of beans compared to a real test.
If it's HPA......just get it tested.
Mike
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There is tubing available in air hardening alloys, but whether or not it was used by Benjamin is debatable, and in all actuality probably really remote.
My main point in using that as an example was more of a what if scenario.
I have destroyed many items in the name of modification, and escaped serious injury a few times. Due to that, I always err on the side of caution, and assume worse case scenario.
It may turn out to be a proven mod through repeated use, but I don't really want to be the guinea pig if you know what I'm saying!! ;)
I wish him lots of luck with the mod, and hopefully it gives good accurate service.
But air hardening steel is typically used when it will be heat treated for hardness...the only air hard I would expect to see in a firearm where tubing might have some applications would be S7, and while I have never LOOKED for it in tube form, neither have I seen it listed. And to get any heat affected zone from re heat treating the metal would mean heating it to 1750F or so for S7 and A2....1850 for H13.
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Some people have thin skin and take offense easier than others if the intent was about safety and s serious injury potential existed then I would rather unintentionally insult someone and see them remain uninjured than remain silent and see one person injured due to my silence
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There is tubing available in air hardening alloys, but whether or not it was used by Benjamin is debatable, and in all actuality probably really remote.
My main point in using that as an example was more of a what if scenario.
I have destroyed many items in the name of modification, and escaped serious injury a few times. Due to that, I always err on the side of caution, and assume worse case scenario.
It may turn out to be a proven mod through repeated use, but I don't really want to be the guinea pig if you know what I'm saying!! ;)
I wish him lots of luck with the mod, and hopefully it gives good accurate service.
But air hardening steel is typically used when it will be heat treated for hardness...the only air hard I would expect to see in a firearm where tubing might have some applications would be S7, and while I have never LOOKED for it in tube form, neither have I seen it listed. And to get any heat affected zone from re heat treating the metal would mean heating it to 1750F or so for S7 and A2....1850 for H13.
I'm with you, believe it or not... ;D
Air hardening tubular steel is used a lot in the bicycle manufacturing world.
I wouldn't think it too far of a stretch to immagine some penny pinching bean counter substituting similarly dimensioned tubing for another alloy with no other thought in mind other than final cost of product shipped.
-Insert cheap Chinese alloy steel bashing rant here. -
Such an alloy in its annealed state, or machine ready state, may not pose any problems to machining operations prior to assembly, and go unnoticed.
Pure conjecture, I am aware of that fact, but stranger things have happened.
All metallurgy questions aside, I'm still a bit leary of modifying a pressure vessel unless it is a proven process.
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There is tubing available in air hardening alloys, but whether or not it was used by Benjamin is debatable, and in all actuality probably really remote.
My main point in using that as an example was more of a what if scenario.
I have destroyed many items in the name of modification, and escaped serious injury a few times. Due to that, I always err on the side of caution, and assume worse case scenario.
It may turn out to be a proven mod through repeated use, but I don't really want to be the guinea pig if you know what I'm saying!! ;)
I wish him lots of luck with the mod, and hopefully it gives good accurate service.
But air hardening steel is typically used when it will be heat treated for hardness...the only air hard I would expect to see in a firearm where tubing might have some applications would be S7, and while I have never LOOKED for it in tube form, neither have I seen it listed. And to get any heat affected zone from re heat treating the metal would mean heating it to 1750F or so for S7 and A2....1850 for H13.
I'm with you, believe it or not... ;D
Air hardening tubular steel is used a lot in the bicycle manufacturing world.
I wouldn't think it too far of a stretch to immagine some penny pinching bean counter substituting similarly dimensioned tubing for another alloy with no other thought in mind other than final cost of product shipped.
-Insert cheap Chinese alloy steel bashing rant here. -
Such an alloy in its annealed state, or machine ready state, may not pose any problems to machining operations prior to assembly, and go unnoticed.
Pure conjecture, I am aware of that fact, but stranger things have happened.
All metallurgy questions aside, I'm still a bit leary of modifying a pressure vessel unless it is a proven process.
Hmm I never thought about bearing races :-)...that would indeed be a good use for such a thing :-). Most of my metal working experience has been "tool and die" and agricultural-automotive. Maybe I need to get out more :-).
And I do agree about modifying pressure vessels.
Bill
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I was stationed on a sub tender and submarines are the ultimate pressure vessels I know this is a side trip but the point is any time the hull was breached for a new through hull fitting after the welding was completed x rays and magnaflux tests were performed to insure that the work was safe when everything was completed. 2500 psi is a lot of pressure is dramatic if the vessel were to rupture due to heat induced fatigue and the resulting metal fragments could very well be lethal or at the least make one *(&^ of a bang
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I have read this all and I am not going to comment on the guys braze joint as I can't see it very clearly. I understand the pinhole safety factor. All I know is to get a good bond it needs to get really hot and the paint on the tube does not show that to me?
This is a silver soldered brazed test cap that was under just 250psi when it failed. It was one of my first big (12" x 12') chillers that I made. It is a 2.5" inch diameter and .098" thick CUNI (copper nickel) butt jointed to a 2" ID suction tube. I was fairly new at brazing and you can clearly see from the picture that the flux did not get hot enough on the right pic to run clear and the joint was weak (cold joint). Granted this is now pretty oxidized after 8 years and is no longer pink and shiny.
(http://i40.tinypic.com/2evcdq1.jpg)
When it let go, I was 1-2' away and there was no warning at all. It hit me in the right side sending me 20ft in the opposite direction ripping off 2 jackets and my shirt. I am still picking flux out of my skin to this day as it works it's way to the surface. Luckily it just knocked the wind out of me, caused some minor internal bleeding and a bunch of road rash but it could have been much much worse..
Be safe!!
PS. Thanks for looking out for us Bob. Feelings heal faster than flesh!
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Maybe so, but time to put this YEAR OLD thread to rest....
Bob