Over filling cylinder

[Gwhite]

The only other Morini cylinder failure I'm aware of occurred about 5 years ago. Lab analysis blamed the failure on the owner's use of chlorinated gun solvents on the cylinder. There were scratches in the anodizing, and the chlorinated solvents attacked the aluminum through the scratches. I believe that cylinder failed at normal working pressures.

Morini asked owners to send them cylinders from a certain date range to make sure it wasn't due to a manufacturing defect. I sent one (or two?) cylinders to them, and they returned them after verifying that they were OK. I don't know of anyone who had their cylinder rejected as dangerous. Before the ISSF put the 10 year rule into effect, Morini cylinders had a 20 year service life. I have no concerns using my cylinders for practice past the 10 year limit.

[marky-d]

Yes, over-filling can be dangerous, but I think it's interesting that some people thing it's a black-and-white sort of situation. As someone mentioned, the test pressures of cylinders are typically at least 150% the rated pressure, and the RUPTURE pressure is typically much much higher than that.

So is there a chance that a cylinder could rupture if it is rated to 200bar (2901psi) and you fill it to 205bar (2973psi)? Yes, but only if it is damaged, and it's just about the same likelihood it is going to rupture if you filled it to only 200bar!

Additionally, the anonymous source in the article implied that for some reason the chance of failure immediately goes up as soon as the 10yr "life span" of a cylinder is exceeded, which I've also seen regurgitated on this forum. There is nothing magical about day 3651 of a cylinder's life that suddenly makes it likely to rupture when it wouldn't have on day 3649.

It's all about degradation and damage, and most air gun cylinders live a pretty charmed life. They normally don't get dropped. They normally don't see extreme heat, cold, or wear and tear. They don't typically even see cleaning chemicals like a firearm would.

As I think someone else already mentioned, refilling a cylinder is the most dangerous time with the cylinder, and if it can be done in a blast cabinet, that's a great idea. After refilling high pressure cylinders for years using such cabinets, I always think twice about filling my cylinders without one, but I do it anyway. It's a lot like wearing a seat belt: if you grew up wearing one every time you rode in a car, it probably feels weird NOT to wear one now, but it is extremely unlikely you will get hurt if you don't.

The problem, of course, is that one time you should have worn the seatbelt....
And similar to your air cylinder, if something goes wrong, it may be your fault (purposely overfilling) or it may be something you can't control (unseen damage to the cylinder). You need to understand and be comfortable with the level of risk that is there.

marky-d

[m1963]

Your analogy is a good one.

My brother has always refused to wear a seat belt. About 4 weeks ago he was driving home, and swerved to avoid a deer at about 1800 (early dark, here. also right about time change). The dually truck tires, on his truck caught the pavement and sent him over the road, and into a creek. Without a seatbelt he broke his left pelvis, right ankle, and planted his head in the windshield. He crushed his ribs on the steering wheel. He spent 14 hours in a creek with water washing over him, before he was found.

He is alive. Replaced pelvis. Still not allowed to walk...maybe next year. He will never work again- so says the Occupational Therapist.

Wear a seatbelt. Follow fill rules.

[David M]

One of the scary things in India is the availibility of 300 bar bottles for refilling.
Too easy to overfill....

[dulcmr-man]

If one has a 300 BAR cylinder, shouldn't a regulator be used to ensure against overfilling? If so, where would one buy such a device?

Dennis, aka Dulcmrman

[Gwhite]

Best Fittings in England sells one, but it costs an arm and leg:

https://www.bestfittings.co.uk/shop/air ... ssure-air/

The "full kit" is 350 Pounds.

You CAN safely fill a 200 bar cylinder from a 300 bar tank IF you know what you are doing, are VERY careful, and have a fill system with a high quality gauge and a flow restrictor. Relying on the cylinder's gauge is asking for trouble.

[Rover]

I've found the cylinder manometers are crap, and besides being inaccurate, frequently leak. Unfortunately, you're stuck with them, but if you're buying aftermarket, you may be able to find cheaper, more dependable cylinders.

[dulcmr-man]

Best Fittings in England sells one, but it costs an arm and leg:

https://www.bestfittings.co.uk/shop/air ... ssure-air/

The "full kit" is 350 Pounds.

You CAN safely fill a 200 bar cylinder from a 300 bar tank IF you know what you are doing, are VERY careful, and have a fill system with a high quality gauge and a flow restrictor. Relying on the cylinder's gauge is asking for trouble.

I have been filling my pistol using a 300 bar tank with a restrictor, but the photos posted in this thread have given me pause for thought. I will keep looking for a less expensive alternative.

Dennis, aka Dulcmrman

[Gwhite]

I've often thought that somebody SHOULD make a small, non-adjustable 200 bar "safety" regulator that you could use with higher pressure tanks. I suspect a lot of the cost of the one from Best Fittings is the two high quality gauges, which are a good idea anyway. Combined with a flow restrictor and a push button relief valve, it would be very nice, but it will never be cheap.

[Gwhite]

I've often thought that somebody SHOULD make a small, non-adjustable 200 bar "safety" regulator that you could use with higher pressure tanks. I suspect a lot of the cost of the one from Best Fittings is the two high quality gauges, which are a good idea anyway. Combined with a flow restrictor and a push button relief valve, it would be very nice, but it will never be cheap.

[mus]

Somebody does:

https://www.huma-air.com/Externally-Adj ... ed-Fillset

This is externally adjustable but since it has a bleed screw one could, once adjusted to 200 bar, either leave it on the scuba tank after closing its valve and bleeding to be able to take the filled cilinder off, or remove the regulator without altering its setting so next time the tank's valve is opened (slowly!), the regulator will prevent overfilling to more than 200 bar.

[Gwhite]

Nice! This one has three adjustment ranges (possibly a regulator spring swap?). If you pick the one that has a 200 bar maximum, nobody could adjust it higher (by accident or intentionally). Because it has a 300 DIN fitting on the output side, you would need one of the dreaded adapter rings to use it with 200 bar fill adapters.

Still a LOT of money...