May be of interest to some here:

http://www.hse.gov.uk/safetybulletins/aluminium-cylinders.htm?eban=govdel-safety-bulletins&cr=18-Apr-2018

Thanks Nick; I've just bounced that over to the members' side of the CDG message board.

The warning points out that "any cylinders still in use are between 23 and 55 years old."

Just out of interest, how long do (cave) divers usually keep cylinders for?

Roger W said:

Just out of interest, how long do (cave) divers usually keep cylinders for?

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I have some cylinders that were bought in the early 90's - still tested regularly.  Providing they are looked after then cave divers' cylinders can last a long time - they are generally only used in fresh water.  The problems come with rust and overfilling.

Roger W said:

The warning points out that "any cylinders still in use are between 23 and 55 years old."

Just out of interest, how long do (cave) divers usually keep cylinders for?

Click to expand...

Till they fail their test.

The regular cylinder tests (hydrostatic and visual) are the most reliable way to determine whether a cylinder is safe or not. Age alone is no real guide, as its safety depends on how a cylinder has been treated during its working life (i.e. umpteen variables). If a cylinder was acquired second hand then the latter cannot be reliably known anyway. Divers may start to become concerned about a cylinder's safety based on superficial appearance or mere gut feeling. The correct course of action in such circumstances it to empty it safely then have it tested ahead of the next scheduled test. If it fails then there's usually little or no cost. If it passes you get peace of mind.

Personally, I've always preferred steel cylinders. To my mind the only real advantage of aluminium cylinders is their buoyancy characteristics when scootering along with several of them as stage cylinders. My view is that, for almost all British cave diving, steel is probably best. Cave diving overseas is a different kettle of fish of course.

Pitlamp said:

. Cave diving overseas is a different kettle of fish of course.

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Please don?t put fish in kettles



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how else are you going to cook them?

Leaving them in the sun on the beach works well

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ah147 said:

Pitlamp said:

. Cave diving overseas is a different kettle of fish of course.

Click to expand...

Please don?t put fish in kettles



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Click to expand...

(Grins)

That reminds me of one hungover morning many years ago in a certain caving club hostel, when the gas for the cooker ran out. Facing the prospect of no breakfast, one of the senior members boiled a couple of eggs in the electric kettle, then promptly made a brew with the same water. They were free range eggs from the local farm and I remember laughing at him spitting feathers out whilst drinking the brew. Then again, he got a breakfast and we didn't.

Pitlamp said:

ah147 said:

Pitlamp said:

. Cave diving overseas is a different kettle of fish of course.

Click to expand...

Please don?t put fish in kettles



Sent from my iPhone using Tapatalk

Click to expand...

(Grins)

That reminds me of one hungover morning many years ago in a certain caving club hostel, when the gas for the cooker ran out. Facing the prospect of no breakfast, one of the senior members boiled a couple of eggs in the electric kettle, then promptly made a brew with the same water. They were free range eggs from the local farm and I remember laughing at him spitting feathers out whilst drinking the brew. Then again, he got a breakfast and we didn't.

Click to expand...

It probably wasn't just feathers...  :yucky:

Precisely . . .

I suppose if he had boiled his eggs properly, he would have killed off most of the bacteria from the chicken's bum...

I daresay you could make quite a decent kettle to boil eggs (or fish) in by cutting down an old alloy cylinder?

This is, of course, way off topic (though I suppose it could be regarded as a health & safety issue) ? but Pitlamp?s post above reminds me of an incident at a caving club hut, where the regulars used to pour used fat into a pint mug on the window sill. One morning some luckless individual put down his pint mug of tea next to the ?fat mug?, into which someone had just poured his breakfast fat . . . you guessed it; fortunately for said individual the fat was relatively cool by the time he tried to drink it.

Wowzers! Lucky escape, though drinking cool fat is still an absolute nightmare!

There has been diminishing enthusiasm for aluminium bottles in recent years after accidents. I know one person in Cornwall (sadly he died not long ago) who refused to fill aluminium bottles anymore. When I started diving in the 60's we used twin tadpoles that were low pressure and mostly ex WD from the air force. In the 70's filling operators got a bit wary of them even when they had passed test. One of my bottles is probably of an equivalent age to one of those tads come to think of it. However it passes its test regularly and was bought from new. External apprearance is nothing to go on. I bought an immaculate looking tank a few years ago (second hand) and it failed testing immediately as it had been stored on its side allwing rust to eat into the thinnest part. I got my money back (not the test money though).

Many dive clubs had their own compressors and were not too fussy about cylinders being in test. Like Mr O. Doc I had an early ali cylinder that had been used to test diving watches. I found that they got easily damaged externally. I do remember the auto fill air machine at Lyme Regis. Now that was a daft idea as you could fill any old cylinder. It did not last long. Being a tight old sod I used heliair for technical diving as , in theory , you do not need to o2 clean the regs or cylinders. We were having a safety talk on the boat once and a cylinder containing %60 o2 caught fire. Rather the HP hose did when it burst.( Had that on a dive once. Nearly blew me head off ). It whipped around like a flame thrower burning the adjacent kit. My bottle got scorched and my mate ( a fireman ) lost his shorts which were on the bench. People seem to forget that stab jacket inflation bottles, which can be ali ,should also be tested but because you fill them off your main set rarely are. I have also had a new cylinder fail it's first test through internal corrosion. Normally the testing station will wreck the internal thread so that it cannot be used again.