An accident. Take care please. Playing with HPA is not a joke

[Xbowsniper]

Nation,

I know for a fact, that one major airgun manufacturer that designs guns to hold 3000 psi, tests those vessels at 9000 psi. When you get a 4500 psi tank pressure tested, they test it to around 15,000 psi, or just short of it.

Personally, withstanding twice the given psi in a test, is NOT enough!!!!

Tom Holland 

Field Target Tech 

Fieldtargettech.com 

 

[brawler1588]

I was talking to Ernest and he pointed out he only saw 3 threads on the end of vlads plenum I don't know his work or maybe he has improved on his design but Ernest said 7-8 threads minimum. Like I said I don't know Tyler personally but we have become good distant friends. Look at the threads and wall thickened compared to a Ernest plenum....

 

[triggertreat]

Hope his healing is lightning fast, and that he doesn't get scared off by learning a hard lesson created by others. I do use light weight aftermarket air cylinders in my two Marauders. But, I know who tested them (Lloyd Sikes, AKA "The mad scientist") for over a 3:1 safety ratio while filming a video to watch the testing. I have already experienced the power of 4500 psi, but came out okay with just a bruised finger. That's all I needed to up my safety game.

 

[Guest]

If there is only 3threads this is kinda big serious situation and ppl should stop using them ASAP before someone dies. This is once again deadly serious situation like texan reg from pcp tunes was and should be treated as such. EVEN ONE IS TOO MANY. 

 

[mubhaur]

If there is only 3threads this is kinda big serious situation and ppl should stop using them ASAP before someone dies. This is once again deadly serious situation like texan reg from pcp tunes was and should be treated as such. EVEN ONE IS TOO MANY.

It could have that only 3 threads left there and the rest got away during the explosion. 

I can't think the 3 threads can ever be relied.

All my scuba tanks are marked as Working pressure of 300 bars and testing pressure of 450 bars.

This is not even 200%. If 200% the testing pressure should have been written as 600 bars.

so I just tried to exceed the written standard on scuba tanks. Its good that no issue till now. Further I keep the thickness of that area where threads are made so that when both sides of threads are matched even then both independent male and female thread should strong enough for what it has been designed. 

Bhaur

 

[brawler1588]

If there is only 3threads this is kinda big serious situation and ppl should stop using them ASAP before someone dies. This is once again deadly serious situation like texan reg from pcp tunes was and should be treated as such. EVEN ONE IS TOO MANY.

It could have that only 3 threads left there and the rest got away during the explosion. 

I can't think the 3 threads can ever be relied.

All my scuba tanks are marked as Working pressure of 300 bars and testing pressure of 450 bars.

This is not even 200%. If 200% the testing pressure should have been written as 600 bars.

so I just tried to exceed the written standard on scuba tanks. Its good that no issue till now. Further I keep the thickness of that area where threads are made so that when both sides of threads are matched even then both independent male and female thread should strong enough for what it has been designed. 



Bhaur

Tyler said the metal itself failed and bowed causing the threads to slip and fail I guess I told him to try and find the cap but God knows where it when it made it through the house and outside. 

 

[mubhaur]

If there is only 3threads this is kinda big serious situation and ppl should stop using them ASAP before someone dies. This is once again deadly serious situation like texan reg from pcp tunes was and should be treated as such. EVEN ONE IS TOO MANY.

It could have that only 3 threads left there and the rest got away during the explosion. 

I can't think the 3 threads can ever be relied.

All my scuba tanks are marked as Working pressure of 300 bars and testing pressure of 450 bars.

This is not even 200%. If 200% the testing pressure should have been written as 600 bars.

so I just tried to exceed the written standard on scuba tanks. Its good that no issue till now. Further I keep the thickness of that area where threads are made so that when both sides of threads are matched even then both independent male and female thread should strong enough for what it has been designed. 



Bhaur

Tyler said the metal itself failed and bowed causing the threads to slip and fail I guess I told him to try and find the cap but God knows where it when it made it through the house and outside.

Wherever there are threads the thickness is duly increased to reinforce the strength. I normally follow this approach to further avoid issues. 

Bhaur 

 

[TeOh1776]

Wow! That is unfortunate but fortunate he wasn't seriously hurt. 

 

[tor47]

If there is only 3threads this is kinda big serious situation and ppl should stop using them ASAP before someone dies. This is once again deadly serious situation like texan reg from pcp tunes was and should be treated as such. EVEN ONE IS TOO MANY.

It could have that only 3 threads left there and the rest got away during the explosion. 

I can't think the 3 threads can ever be relied.

All my scuba tanks are marked as Working pressure of 300 bars and testing pressure of 450 bars.

This is not even 200%. If 200% the testing pressure should have been written as 600 bars.

so I just tried to exceed the written standard on scuba tanks. Its good that no issue till now. Further I keep the thickness of that area where threads are made so that when both sides of threads are matched even then both independent male and female thread should strong enough for what it has been designed. 



Bhaur

Tyler said the metal itself failed and bowed causing the threads to slip and fail I guess I told him to try and find the cap but God knows where it when it made it through the house and outside.

Wherever there are threads the thickness is duly increased to reinforce the strength. I normally follow this approach to further avoid issues. 

Bhaur

When the O-rings on the endcap are at the end facing inward the tube, the threads are under no pressure. T

 

[Centercut]

When the O-rings on the endcap are at the end facing inward the tube, the threads are under no pressure. T

Really? So we don't need the threads at all then do we... I think you meant to say that air pressure is retained by the orings and the joint made between the cap and the cylinder. Of course the threads have stress on them, that is what keeps the cap from blowing off and going to the moon...

One thing that baffles me, is that in almost two pages of comments, no one has said who made this unit? Why protect the person that put many shooters in an unsafe condition?

 

[Xbowsniper]

Centercut,

I believe it's one of Vlads units that failed. 

Tom Holland 

Field Target Tech 

Fieldtargettech.com 

 

[Centercut]

When you get a 4500 psi tank pressure tested, they test it to around 15,000 psi, or just short of it.
Personally, withstanding twice the given psi in a test, is NOT enough!!!!

Tom Holland

In the USA, 4500 psi SCBA tanks are "tested" to 15,000 psi, but not all of them are actually tested from what I can gather. For each lot of materials and assembly process, a certain number are chosen from that lot to test (per DOT standards). They are pressurized to 15,000 psi, held for a short time (one minute?), then pressurized to failure. The MINIMUM passing is 15,000 psi for that lot. If you take your SCBA tank in for its 5 year hydro, that's to 7500 psi, and held for one minute (5/3 SWP)

If you look at the printing on DOT tanks, they show a Safe Working Pressure (SWP), and a Maximum Safe Pressure (MSP). On most of our airguns, the bottles have a SWP of 250 bar and a MSP of 310 bar (or higher). Umar said that his Design Pressure is 800 bar, and his Test Pressure is 400 bar. Working pressure is 200 bar. From an Engineering standpoint, that looks good to me...

 

[Xbowsniper]

Centercut,

His full name is Vladan Pani Paunovic.....

Tom Holland 

Field Target Tech 

Fieldtargettech.com 

 

[Centercut]

Thanks Tom, maybe he can weigh in on the material and thread design. A the top of page 2 it shows about two or three threads, which is totally unsatisfactory. But the photo below looks like one of Ernest's power plenums for Cricket, and they are aluminum, not steel... We need to compare apples to apples...

 

[Xbowsniper]

Centercut, 

You are correct. And to add on what someone else said above, everyone is talking about the plenum holding under 3000 psi. That plenum SHOULD be able to hold 4500 psi. Why? When a regulator fails, it almost always let's the full pressure of the tank past it. We now have companies putting 4500 psi rated tanks on guns with regulators on them, to get more shots without refilling. This creates a problem downstream, so to speak, because those parts were not designed for 4500 psi. Because of the above reason, they all SHOULD be.

Tom Holland 

Field Target Tech 

Fieldtargettech.com 

 

[Guest]

Name of his reads on the starting post on screen capture and there might be hundreds of his rather popular plenums around thats rather disturbing. Hope this captures everyone and all of them realise not to use it. Even one failure kinda says design or/and materials used aint up there for safe usage. Hope we dont get idiots around protecting him like we got with pcp tunes texan plenum explosion. Even one is unacceptable in everyway and ppl been just lucky to survive in both cases. When we are playing with compressed gasses and metal structures we are speaking of live handgranades next to someones head and there is ZERO tolerance to bad designs and materials PERIOD. Impact max filling pressure is 250bars and that plenum should be tested atleast up to 500bars and shouldnt have any deformations up to 750bars. Even some burst disks at regulated side it should be tested atleast to 500bars and seeing this happened probably much before even reaching that systems max potential of 250bars with regulator completely gone and no emergency burst disk this should have never happend and this regulator 100% :ly was never pressure tested to proper safety margings. 

 

[brawler1588]

Thanks Tom, maybe he can weigh in on the material and thread design. A the top of page 2 it shows about two or three threads, which is totally unsatisfactory. But the photo below looks like one of Ernest's power plenums for Cricket, and they are aluminum, not steel... We need to compare apples to apples...

I am not sure what Ernest plenum that was from its justvthe picture Ernest sent me when I told him. But I just pulled mine to snap a picture if it helps any from my Ernest Impact I have.

 

[Centercut]

I am not sure what Ernest plenum that was from its just the picture Ernest sent me when I told him. But I just pulled mine to snap a picture if it helps any from my Ernest Impact I have.

Thanks, that looks much better, although some of the high pressure vessels I've seen have even more threads than that... As far as materials, I've seen Stainless Steel (usually 304, but 316L in external hydraulics systems that operate in seawater) used in nuclear power plants for high pressure systems. Monel (NiCu) is also used frequently. 

 

[tor47]

When the O-rings on the endcap are at the end facing inward the tube, the threads are under no pressure. T

Really? So we don't need the threads at all then do we... I think you meant to say that air pressure is retained by the orings and the joint made between the cap and the cylinder. Of course the threads have stress on them, that is what keeps the cap from blowing off and going to the moon...

One thing that baffles me, is that in almost two pages of comments, no one has said who made this unit? Why protect the person that put many shooters in an unsafe condition?

You are correct. I meant there will be no air pressure from the 0-rings and out. So the only force acting on the threads are from the air in the sylinder pulling on the endcap in one direction (if you do not over thigthen the endcap while assembly). That is offcorse still allot of force. So the threads still need to be long enough. And not big, so they do not weaken the tube itself.

It is from an enginering point of view better to have the O-rings on the endcap sealing off the air inside the tube, so the threaded part is pressure less, as it allows some thinner walls on the threaded part. Mubhaur have done it "correctly" in that regard. Ernest have the O-ring sealing after the threads which basically mean the tube will have it`s weakest point where the threads start. I do not say Ernest way of doing it is unsafe, as it in the end comes down to the dimensions and materials used.

 

[GeneT]

I am not sure what Ernest plenum that was from its just the picture Ernest sent me when I told him. But I just pulled mine to snap a picture if it helps any from my Ernest Impact I have.

Thanks, that looks much better, although some of the high pressure vessels I've seen have even more threads than that... As far as materials, I've seen Stainless Steel (usually 304, but 316L in external hydraulics systems that operate in seawater) used in nuclear power plants for high pressure systems. Monel (NiCu) is also used frequently.

An engineering rule of thumb is that you get about 95% of your possible strength with the first five threads. Each thread thereafter bears a smaller percentage of the load (but also provide a failsafe). There are exotic threadforms (like Spira-Lock) which distribute the load more evenly, but I've never seen them used in airguns.

GsT