Air tank questions

[rcs9250]

I understand your safety concern and yes, the potential for explosion is there, but I think the risk is overstated. It is certainly not zero, but I suspect it is very low. In years gone by, tank failure was almost always because of corrosion, but when the tanks failed, they generally leak first. The aluminum SCUBA tanks were a different story to some extent because aluminum has poor fatigue strength. Since today's aluminum tanks are generally wrapped in CF they don't swell very much if at all when filled, so fatigue does not occur and expected tank life is greatly extended. Of course corrosion is still an issue, but not so much for explosions. i believe, that tank testing is hydraulically pressuring the tank to test pressure and measuring the amount of diameter swell that occurred., but since hardly any swelling occurs in CF wrapped tanks, that test is pretty much invalid. Most replaced tanks today are replaced based on age almost alone, which is really wasteful. If the tank is visually inspected and has no corrosion, there is no reason to replace it. If however the CF is damaged, that's another story.

Hey, I am fine with people blowing themselves up. It makes for interesting reading.

 

[Ezana4CE]

Hey, I am fine with people blowing themselves up. It makes for interesting reading.

@rcs9250 Who is doing this?

 

[grackleblast]

Hey, I am fine with people blowing themselves up. It makes for interesting reading.

Huh ? What ? Inquiring minds want to know...........................

You know something the rest of us don't ?????????????


FYI I haven't had any tanks explode on me this week , but , in all honesty............................it's only Tuesday .

 

[Ta-Ta Toothie]

Each to its own. I will only purchase a new DOT tank from a reputable dealer.

 

[grackleblast]

Each to its own. I will only purchase a new DOT tank from a reputable dealer.

This drives an industry that thrives on the notion that tanks at a certain point can be unhealthy for the public. Therefore, one should make their own choices based on the available information. Knowledge is a valuable tool . Each should do their due diligence and make an informed choice.

 

[zerochance]

I really appreciate everyone's opinion. Before buying a non-DOT approved air tank, I should call around and see if any shop is willing to do a hydro test without being DOT approved. I have a feeling most shops will say no as it is a risk factor the shop has to take.

 

[AlanMcD]

I really appreciate everyone's opinion. Before buying a non-DOT approved air tank, I should call around and see if any shop is willing to do a hydro test without being DOT approved. I have a feeling most shops will say no as it is a risk factor the shop has to take.

You will find that most shops will not hydro test a non-DOT tank simply because they can't legaly certify it. I think if you you know the owner well enough, he might do it for you, but pretty much expect that you won't be able to get them tested.

Now, that really is not so bad - as @grackleblast said, we airgunners barely even use these things, compared to what they were designed for. My tanks that were purchased new have only ever been filled with air that has been properly dryed via desiccant, and they see no physical stress other than filling, and that is always just a partial fill (typically 3800 - 4500 or less). My 9L Acecare tank that I have had for 8 months has only been topped off about 12 times in that range, but one that is in use by a firehouse could have had well over 100 full fills from empty to max in that same time frame (plus much harder use). That would be ~280 cubic meters of air compressed into the firehouse tank vs about 8 cubic meters for mine in the same hypothetical example - only about 3% of the usage.

Bear in mind that a hydro test is an overpressure expansion test - it is a bit of "controlled destruction" looking for structural changes in the tank beyond what is allowed. It is by far the most grueling thing you can do to an airgun-only air tank (other than filling it with air full of water vapor, which we absolutely should not be doing). I for one have no plans to hydro test any of my tanks that were purchased new anyways, because there is no point. I will have visual checks done on them, but I'm not subjecting them to a hydro test "just because" some people think it is a good thing to do. I'm sure @rcs9250 thinks this is simply delayed suicide, but it is nowhere close to that . . . .

Understand the regs, and understand the physics involved, and the path will be clear . . . . we all get to make our own choices. Just don't think you have a choice when it comes to needing to properly dry the air you compress - failing to do that may well be in the delayed suicide category.