Phil
What Ray said, and;
There are certain alloys from older AL tanks that are slightly more prone
to fail than others,
http://www.psicylinders.com/library/Current/cracking.htm
These guys are about the first and last word in scuba tank inspection:
http://www.psicylinders.com/
If any common AL tank has that kind of "expiration date", it's the first
I've heard of it.
Back in the 90's, there were a few, and I mean few, AL tank explosions
related to filling, and it set off a spur of all sorts of people simply
inventing all sorts of guidelines, mostly related to selling new tanks.
--
--
Popeye
"If one does as God does enough times, one
will become as God is." -Dr. Hannibal Lector.
www.finalprotectivefire.com
http://picasaweb.google.com/Popeye8762
I appreciate the info, guys
So, if I buy a new aluminum tank, I won't have to worry about a shop
refusing to fill a tank when it gets so old? I understand that a tank
could fail hydrotesting (I used to service and repair fire
extinguishers and stuff). I just don't want to buy a tank for a few
years.
Thanks.
Phil
I would be more concerned with getting a tank that would not pass hydro.
This is an interesting article on the tank failures from almost 20 years
ago. It mentions 12 failures, 6 of them firefighter SCBA (not scuba),
out of how many thousands of tanks out there?
While this doesn't address your question I found this interesting.
Just a side note, there are still thousands of those 6351 tanks in
service and, if not stored full and they get frequent inspections for
neck cracking, should offer their owners years of service ... I have
several. It is just that many dive shops don't want to mess with them
anymore. Doesn't bother me ... I have more compressors than 6351
tanks! ;-)
--
Ray
====================
www.compressorstuff.com
I had a set of Walter Kiddes that I used to get jacked to 4k while they were
on my back..
I'm retiring a couple of aluminum tanks this year that just squeaked by
the eddy current testing in the spring (and then hit their hydro dates a
month ago). The cracks in the threads are visible under magnification.
They are 20+ years old. Had they been better treated by their prior
owner and me, and not left full for extended periods, they would
probably still be fine, but that's how the cookie crumbles. I've got my
money's worth out of them (they were free but needed hydro several years
back) and am not complaining. Tanks are cheap and people are not.
Also, by the time they are hydrotested and O2 cleaned again and the
valves serviced I'm halfway or more to the cost of new tanks.
I have an aluminum tank made in 1972 out of the "bad" alloy. It's still
fine but it's never stored full. I rarely use it these days but this is
because it's an AL72 (kind of rare) and it's quite long and 5 lbs
buoyant when empty, both of which are inconvenient when it's used as a
travel gas or deco bottle.
My other aluminum tanks range in age from 10-15 years and as long as I
treat them well I expect them to last until I'm tired of them. YMMV...
--
John Eells
Hello from Europe/Norway:
I had a really bad experience with a French scuba tank of 10,3litres/200
BAR, - made of the same kind of alloy as the AA-7351-T6.
It was on May 27th. 1997. It flattened out my parets garage in Vestfold
County, South Norway. Luckily nobody was present at the time of the blast.
See this link for info and pictures of this event:
http://www.scubabomb.freeservers.com/Scubadag.htm.
See also the mainsite made after Chris Hawkins' bad accident in Florida
February 1st. 1998, - made by his uncle Dennis Hawkins.
http://www.scubabomb.freeservers.com.
Since then, several tank ruptures has occured with similar tankes made prior
to about 1988. Most all over Europe and EU, such aluminum scuba tanks are
BANNED by national "working safety boards", diving centers, diveshops,
fire-fighters and the rest of the diving communities.
Why risk yourown or your dive buddy's life and lims for just some "bucks"?
Don't use them! You can very well be the next victime since this kind of
aluminium alloy have prooven to weaken over time.
If you own and use such items beware that you risk your lims and/or even
your life if you still fill, use or store them! Get them scrapped A.S.A.P.!
Best wishes from
Dag Deberitz, Stavern Vestfold county, Norway
Mail adress: dagbritz(AT)tele2.no
- nowadays never seen with ALUMINIUM scuba tanks!
I handed one of those in for testing in 01 or 02 (years slip by these
days).
Went to get it back a week later and was given a brand new one instead.
Old one was retired and I got a newie, no questions asked.
Hoges in WA
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