O2 Cleaning : Straw Poll

[Keith L]

I?ve just got my cylinders back from their annual O2 clean. ?90 this year for three cylinders and valves, my small 3L actually failed (rust) and I?m replacing it. The cost breaks down as ?22 per cylinder plus ?8 each for a shot clean, all three of them!

This year I used Kent Divers, a very well known and respected firm who I have no cause to doubt. But they informed me that all three cylinders had rust and needed shot blasting, one failed due to rust.

Now this has got me thinking. Just =WHY= do all three of my cylinders need shot blasting? More to the point how common is this? So a quick straw poll - of those of us who use Nitrox just how many of us have needed this?

Now I can only think of three reasons why all of a sudden, after many years, my cylinders suddenly rust -

+ I don?t take care of them.
VERY unlikely, I?m doing nothing now that I haven?t always done. The cylinders are never stored empty, even when draining down for a fill I leave a BAR or two in there just in case the shop leaves them open. They are normally assembled and disassembled away from water, I take great care that everything is dry when assembling on the boat after a top-up.

+ The dive shops are laying it on a bit.
I don?t for one minute suspect this of Kent Divers. But it has got me thinking - just what is ?acceptable? rust? Has there been a ?drift? in that the very slightest brown mark warrants a shot blast, at the customers expense of course! Of course it will probably be argued that all this rust ?proves? the need for an annual clean!

+ There are a lot of badly maintained compressors out there.
I am beginning to wonder. I actually know where my cylinders have been filled in the past year - DiveLine in Ipswich, DiveCare in Braintree and Kent Divers. When I asked Kent Divers about this they of course correctly said their compressor is perfect, it is fully tested at every service. But is this enough I am now asking?

So just a quick straw poll about the shot blasting of cylinders - how many divers find that they need this? 10%, 50%, 75%???

There could be something wrong here. If we are not capable of looking after our cylinders then will somebody please tell us how it should be done. Just how much real rust is out there? what is the ?standard?? does this ?standard? vary between dive shops? And are we getting what we pay for in our fills? Are the testing standards on commercial compressors good enough? I do not expect commercial fill stations to fill my cylinders with enough vapour to land me with an annual bill, should there be better monitoring?

Food for thought - comments please.

Keith L

[Steve Walker]

+ There are a lot of badly maintained compressors out there.
I am beginning to wonder.


What about a personal filter (about ~?70) ? removes one suspicion.

Re shops and testing, I would have thought that the shop merely sends the tanks away to a testing station, I believe that's the case in my neck of the woods
Cheers
Steve

[TerryH]

Dont know how you want to work out the percentages, but as the
clubs EO for the past 5 years, I have personally taken 26
cylinders (incuding 4 ponies) in for testing every two years
and 6 of these O2 clean every year.

They are stored in the worse conditions, chucked around various
vehicles, loaned out to students etc. and filled in just about
every South coast outfit you can name.

Total number of blasted/resprayed cylinders in that time = 1.

Kent is a bit of an exception as there stuff is done in house
and they are an IDEST station, but I would say that the best
place for cylinder testing etc. is a cylinder tester and not
the LDS.

Still, three cylinders at the same time seems a lot to me.

TerryH

[jp]

Hi Keith
Almost certainly "WHOEVER YOU ARE GETTING YOUR FILLS FROM IS GIVING YOU TOO MUCH MOISTURE"!!

Do you always fill from the same place, might be worth a word in their ear

JP


I?ve just got my cylinders back from their annual O2 clean. ?90 this year for three cylinders and valves, my small 3L actually failed (rust) and I?m replacing it. The cost breaks down as ?22 per cylinder plus ?8 each for a shot clean, all three of them!

This year I used Kent Divers, a very well known and respected firm who I have no cause to doubt. But they informed me that all three cylinders had rust and needed shot blasting, one failed due to rust.

Now this has got me thinking. Just =WHY= do all three of my cylinders need shot blasting? More to the point how common is this? So a quick straw poll - of those of us who use Nitrox just how many of us have needed this?

Now I can only think of three reasons why all of a sudden, after many years, my cylinders suddenly rust -

+ I don?t take care of them.
VERY unlikely, I?m doing nothing now that I haven?t always done. The cylinders are never stored empty, even when draining down for a fill I leave a BAR or two in there just in case the shop leaves them open. They are normally assembled and disassembled away from water, I take great care that everything is dry when assembling on the boat after a top-up.

+ The dive shops are laying it on a bit.
I don?t for one minute suspect this of Kent Divers. But it has got me thinking - just what is ?acceptable? rust? Has there been a ?drift? in that the very slightest brown mark warrants a shot blast, at the customers expense of course! Of course it will probably be argued that all this rust ?proves? the need for an annual clean!

+ There are a lot of badly maintained compressors out there.
I am beginning to wonder. I actually know where my cylinders have been filled in the past year - DiveLine in Ipswich, DiveCare in Braintree and Kent Divers. When I asked Kent Divers about this they of course correctly said their compressor is perfect, it is fully tested at every service. But is this enough I am now asking?

So just a quick straw poll about the shot blasting of cylinders - how many divers find that they need this? 10%, 50%, 75%???

There could be something wrong here. If we are not capable of looking after our cylinders then will somebody please tell us how it should be done. Just how much real rust is out there? what is the ?standard?? does this ?standard? vary between dive shops? And are we getting what we pay for in our fills? Are the testing standards on commercial compressors good enough? I do not expect commercial fill stations to fill my cylinders with enough vapour to land me with an annual bill, should there be better monitoring?

Food for thought - comments please.

Keith L

[matt]

Twin 10s, 6 years old, mixes from 21 to 40%. Never blasted.
Twin 12s. 4 years old air only. Never blasted.
Twin 7ltr 300bar. 10+ years old. Mixes 21 to 100%. Never needed a blast.
3ltr Pony. 7 years old, mixes 21 to 90%. Never blasted.
7Ltr stage. Ex SBA 15+ years old. 3 years diving use. Mixes 70 to 90%. Never blasted.

All cylinders are used regularly and rarely stored full for longer than a couple weeks. Air fills are mainly off our club compressor. Nx fills from wherever.

I am pretty sure I am using the same test station as TerryH.


Regards
Matt

[Phil Laughton]

:Hi Keith,
Sorry to hear you have had to get your cylinders shot blasted, however,if you think the fault is with the air supply, ie. wet, then ask to see the latest air analysis from the compressor and look for the water vapour reading. Commercial air supplies should be tested every month and be to the BS EN requirements.
Phil
=I?ve just got my cylinders back from their annual O2 clean. ?90 this year for three cylinders and valves, my small 3L actually failed (rust) and I?m replacing it. The cost breaks down as ?22 per cylinder plus ?8 each for a shot clean, all three of them!

This year I used Kent Divers, a very well known and respected firm who I have no cause to doubt. But they informed me that all three cylinders had rust and needed shot blasting, one failed due to rust.

Now this has got me thinking. Just =WHY= do all three of my cylinders need shot blasting? More to the point how common is this? So a quick straw poll - of those of us who use Nitrox just how many of us have needed this?

Now I can only think of three reasons why all of a sudden, after many years, my cylinders suddenly rust -

+ I don?t take care of them.
VERY unlikely, I?m doing nothing now that I haven?t always done. The cylinders are never stored empty, even when draining down for a fill I leave a BAR or two in there just in case the shop leaves them open. They are normally assembled and disassembled away from water, I take great care that everything is dry when assembling on the boat after a top-up.

+ The dive shops are laying it on a bit.
I don?t for one minute suspect this of Kent Divers. But it has got me thinking - just what is ?acceptable? rust? Has there been a ?drift? in that the very slightest brown mark warrants a shot blast, at the customers expense of course! Of course it will probably be argued that all this rust ?proves? the need for an annual clean!

+ There are a lot of badly maintained compressors out there.
I am beginning to wonder. I actually know where my cylinders have been filled in the past year - DiveLine in Ipswich, DiveCare in Braintree and Kent Divers. When I asked Kent Divers about this they of course correctly said their compressor is perfect, it is fully tested at every service. But is this enough I am now asking?

So just a quick straw poll about the shot blasting of cylinders - how many divers find that they need this? 10%, 50%, 75%???

There could be something wrong here. If we are not capable of looking after our cylinders then will somebody please tell us how it should be done. Just how much real rust is out there? what is the ?standard?? does this ?standard? vary between dive shops? And are we getting what we pay for in our fills? Are the testing standards on commercial compressors good enough? I do not expect commercial fill stations to fill my cylinders with enough vapour to land me with an annual bill, should there be better monitoring?

Food for thought - comments please.

Keith L

[Darren Woodward]

I had two one year old ponies put in for O2 cleaning. Previously only used with air. Both needed internal blasting due to rust. They had only been filled 6 or 7 times (dont usually plan on using the air in the pony). I was told that for O2 clean there is a much lower threshold of acceptable rust as the elevated level of O2 will speed up rusting.

[Nick McV]

I generally use nitrox for my second dive, so I only have one in O2 test at a time, (Saves on the cost a bit) but have not had them blasted ever - one is about 10ys, the other about 5ys.
My Partners two non nitrox cyls have never been blasted either - one (2nd hand) about 12ys, other 4ys.

I did have my non nitrox pony blasted, however, and blame this on water trapped behind the DIN to A clamp adapter insert when I topped it up (I had an A clamp pony reg, so the insert was never removed).

OTOH, a single damp fill will do the damage, since the elevated O2 pressures will work on the water in the cylinder for ever more (especially with an O2 first blending technique)....or at least until the next clean.

[Chris Cherrington]

I had two one year old ponies put in for O2 cleaning. Previously only used with air. Both needed internal blasting due to rust. They had only been filled 6 or 7 times (dont usually plan on using the air in the pony). I was told that for O2 clean there is a much lower threshold of acceptable rust as the elevated level of O2 will speed up rusting.

The FO2 makes no difference to the speed of oxidization. Whoever told you that is after your money.... !!!!

[Tony Dwyer]

A member of our club has retired and has offered kit for sale. This included two 10 ltr cylinders (one Heiser - one Faber). Handy think I, would make two nice nitrox training cylinders for second dives. They were both quite a way out of test.
Off they go to a dive shop in Chelmsford with instructions to test and if passed O2 clean. What did it cost?

Cylinder 1
Oops! needed a Hydro test = ?25
Ah! O2 clean that will be = ?20
Oh dear, can't get O2 compatible bits for that pillar valve, have a new MDE one at ?40!!! (was not asked about this, they simply swapped it).

Cylinder 2
A visual test = ?20
O2 clean that will be = ?20
O2 conversion kit for pillar valve = ?15 (bloody expensive O rings!)

No shot blasting needed, luckily.

Total cost for two cylinders ?140 and that does not include paying the retired member for the cylinders.

I bought two new Faber 12 ltr cylinders from the same shop only 4 months ago @ ?110 each including O2 cleaning.