EDgun Based on the thread "L2 explouse in UK".

dorcula said:

No. What's shocking is how little evidence of corrosion is visible on the surface which makes this problem hard to detect to an average L2 owner.
If we believe this to be the root cause, then ANY amount of aluminum oxide visible in the tube makes it highly suspect and potentially unsafe to use.

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if corrosion was indeed the root cause. and if. it was then as i mention prier almost all gun manufators now become a concern.

Okay here's some of my thoughts on this. Feel free to correct me if I'm wrong.

I fail to see how this is a satisfactory conclusion in any way. From what I understand, corrosion was likely the main culprit, right? The report states that the tube fractured at the corroded part of the tube. Ed's answer to this, is basically: Only fill this gun with air from these very specific places not everyone has access to, like fire departments and scuba shops. Furthermore, EdGun will continue the status quo, and produce the airtubes in the same manner.

I'm sorry but... what?! May I remind you that the vast majority of L2 owners are NOT on forums like these. They see these guns in a shop somewhere, think it looks cool, and will probably get basic hand pump or small compressor to boot. A lot of retailers recommend these small compressors to their customers, because they are relatively cheap and easy to use. A lot of them have moisture filters too, though they are not perfect. The avarage Joe is not going to pay regular visits to the local fire department to get a refill, and the safety of your product should not rely on that.

Yes, we know moisture inside your PCP should be avoided. But if it happens, it should AT MOST have a negative effect on the longevity of your gun. Not lead to a catastrophic and potentially lethal failure!

I am no engineer by any means, but aren't there coatings or other processes to prevent alluminum from corroding? Couldn't the walls and corner radiuses (radii?) be made just a tad thicker to make absolutely sure this can never happen again? Any extra measures at all? Heck, if you don't want to do a recall and lose money as a company, I'd happily pay 100 bucks for an improved airtube if it means I get to shoot my L2 AND keep my face intact.

I really don't understand why people are okay with this.

BUT.. Wait! Where is the blood on the sharp edges! This is clearly fake! No but in all seriousness. Fascinating stuff!

dorcula said:

If we believe this to be the root cause, then ANY amount of aluminum oxide visible in the tube makes it highly suspect and potentially unsafe to use.

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Any aluminum thing has thin lay of aluminum oxide, that protects one's of corrosion. Anodizing increases this lay, consequently increases corrosion resistance. Aluminum oxide is our friend. But there are some aggressive environments, where aluminum oxide can't resistant. At least for anodizingless. Also excessive surfaces roughness reduces corrosion resistance. As you increase roughness you reduce corrosion resistance.
In those places, where contact O-rings with surfaces, manufacturers have to remove anodized lay to prevent air leak. Because anodized surface has porous structure. But surfaces which contact with o-rings must have roughness, that looks like mirror. Ra1.6 as worst. Probability of corrosion due to moisture air in this case is insignificant.
But if surface has been obtained with rough tool, without anodizing or poor anodized, in moisture environment it will corrode soon or later.
What will happen if corrosion begins on the tension concentrator under pressure? What way you think?
On the pic below my stock reservoir inside.

Hoffman9517 said:

BUT.. Wait! Where is the blood on the sharp edges

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If it would explode during shooting, there would be blood. Not only on sharp edges. But i don't know in honesty how it happened.

DonEnzone said:

May I remind you that the vast majority of L2 owners are NOT on forums like these. They see these guns in a shop somewhere, think it looks cool

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Totally agree with you. So i before.

DonEnzone said:

Yes, we know moisture inside your PCP should be avoided.

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unfortunately it is not always possible.
It's why high pressure reservoir must be not only cool-looking outside, it must have well-engineered geometry and other metrics inside. Including anti-corrosion treatment, surface roughness e.t.c.

DonEnzone said:

I am no engineer by any means, but aren't there coatings or other processes to prevent alluminum from corroding?

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In our case anti-corrosion treatment by anodizing exists mostly on the outer surfaces. But not for prevent corrosion, it's just for pretty looking. This is good, no doubt. But, as we can see, manufacturer doesn't care anti-corrosion treatment of inner surfaces. In combination with tension concentrator, poor roughness, we obtain time-bomb as result. In my opinion.
But as Ed says in russuan "i give a f*ck anybody's opinion".
PS: I'm relative to airgun production in Russia to. Ed has full right to say that this is preconceived notion.
Sorry for my not prefect English if it occurs.

DonEnzone said:

...The report states that the tube fractured at the corroded part of the tube. .... Only fill this gun with air from these very specific places not everyone has access to, like fire departments and scuba shops..... EdGun will continue the status quo, and produce the airtubes in the same manner.
.... The avarage Joe is not going to pay regular visits to the local fire department to get a refill, and the safety of your product should not rely on that.

.....

I really don't understand why people are okay with this.

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OK, lets project "some" people's attitude to other examples from life:

- Audi for example recommends using 91 octane gas in their cars .... some people asking on the forums "can they fill 87?" and I would bet for a case of beer that there are people filling the $50K car with cheapest possible fuel. What to say about that warranty claim, because sooner or later will surface.
- in HomeDepot people shopping for some fancy dimmer switches and asking how to diy because the certified electrician bill is out of their mind. Guess what is first when the fireman arrives?
- in HD again people buying parts to connect the new barbecue to a house/residential gas line ... knowing that the Insurance Company will reject just anything if the project goes South.

And these story's goes on and on.

You buy an PCP airgun but expecting what exactly ? you will make some fun ?

pan60 said:

if corrosion was indeed the root cause. and if. it was then as i mention prier almost all gun manufators now become a concern.

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Yes. A very big "if".

Look at the page 5 of the report, I missed this part upon the initial reading.

There is no way we would see such thinning of the walls under normal operating pressures, corrosion or no corrosion. Not now when we know that the material of the reservoir is what it's supposed to be, and there are no metallurgical defects or evidence of metal fatigue. Yet, there is a thinning of the walls under tensile load.

I bet this is an overpressure event. Corrosion simply created a weak spot in an unusual place. Chances are, without it, it would've failed elsewhere.



Or maybe someone did grab the rifle by the barrel and hit it hard against a tree, hitting it with the end of the air reservoir. That would also create tensile load at the base of the tube.

Thank you Ed for providing the findings. Not what I wanted to hear but it is what it is.

The sharp corner design is fine with me from a mechanical standpoint. I believe it is sound as far as just pressure is concerned.

The sharp corner from a corrosion standpoint is not. I have been studying the effects of stress corrosion cracking (scc). I have learned that higher stressed areas in the stronger aluminum alloys are highly susceptible to scc.

I am convinced that using clean/dry air will eliminate this being a concern. In my case however, I have already filled multiple times from a ‘cheap’ compressor. I use what is within my means for moisture removal but I am not confident I have always removed all the moisture. Since scc is not always easily detected (especially in this particular tube), I’m not convinced my tube is corrosion free.

As such, I will be taking this tube out of service, along with the lower tube which has same vulnerabilities.

I am not placing blame upon the manufacturer. I do not have a source for dry air locally and used what I felt at the time was sufficient.

I understand that all materials are susceptible to corrosion but it appears to me that this design SEEMS to be more susceptible. Due to the stress in that corner.

Be safe,
Dave

Thanks for sharing. It appears to be caused by operator error but corrosion due to poor air quality is certainly something that occurs on other products in the industry? Yet very few explosive failures are caused by corrosion in the industry? Lets hope there is nothing unique to the design of the L2 that makes it more susceptible to explode due to corrosion than other airguns. Considering the quantity of L2s in use we should know within a few years. Time will tell.

If anything, it is certainly a good reminder. Everyone should be aware of the potential for corrosion to compromise the safety of airguns. We should all be reminded that clean air and regular inspection should be a common practice to assure a safe operation of our airguns.

I always use extensively filtered air and will inspect my L2 on a regular basis. I feel comfortable to take it up to 300BAR again.

Right or wrong, the square corner on a machined pressure vessel still bothers me.

Hi Ed,
I want to know if the process of drilling pipes from solid workpieces is not cooled with water. The drilling process heats up the workpiece so much that it can degrade the material.
It's only a very small probability out of thousands of things you do, but it's not impossible!

How can you imagine drilling that diameter hole to such a depth without a coolant?
The only one sort of machining that will not stress a material (any metal material removal) is only possible with EDM - to some extent.
Myself kind of engineering minded with over 40 years in fabrications and design around my neck... just to explain mu view.

He dropped the gun, that is what I believe otherwise he would have been seriously injured by the blast

Since this is a single event it's reasonable to believe that 99% of mfg guns are structurally sound. I personally appreciate the open attitude that edgun has demonstrated with their analysis. Metal fatigue, corrosion, changes to the assembly weakening the structure are all something that we need to be reminded of I believe to continue to have a safe experience with high pressure devices.

Are their any manufacturers or other organizations that provide cost effective inspections on tanks like some motorcycle helmet manufacturers provide for their equipment?

Denchik said:

I've bought my L2 18 July. In the main I was statisfacted with one, until i read bout this issue today. I've changed stock reservoir with composite bottle 0.36L before. Impressed with this event i started investigate my reservoir. I was wondered when i saw 90 degrees sharp corner inside. In my oppinion it isn't acceptable. This is tension concentrator under pressue. Eduard, how can you tell L2 owners "you can fill your L2 up to 300bar". But there is another pic from your sourse. There is much difference between bottoms.
I've made 3d of my stock reservoir, measuring with caliper. I didn't shape bottom of reservoir according U-type drill, which shaped this bottom with. It doesn't matter.
View attachment 385169View attachment 385170View attachment 385172

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hi Denchik, i am looking to build a new pcp with the leshiy 2 exhaust principle. if possible can you send me this 3d design or a full picture