tank age help

[insane04]

found a guy with 25 AL80 tanks. gonna go look and have looked at other threads about tanks too old to get hydroed. 1990 or newer?

 

[pasley]

Any tank can get a hydro test. But the issue is the AL Alloy used. See this link for infor about the issue: http://www.scubabomb.freeservers.com/List.htm

Many dive shops (for example here in Los Angeles that is most of the dive shops) refuse to fill any pre 1990 AL tank regardless of who made it or the alloy used. Those that will fill them often require you have an eddy-current test done with the annual Visual Inspection which of course cost more money. I don't blame them. It is a safety issue for them and an chance to sell more tanks.

Bottom line, if they are pre 1990, unless you have identified seveal shops in the area (just in case the only one in town that would fill goes out of business), they are worth about scrape metal price ($15 the last time I scraped one).

The issue is not age it is the Alloy they are made of. If they are pre-1990 Luxfer, Walter-Kiddie, or any other brand but Catalina, they are of the alloy that had issues with exploding (mostly in Florida where "cave fills" of +10% were supposedly common.). The theroy is the repeated heating of the metal in these plus fills allegedly changed the composition of the alloy. This is turned resulted in spontainous cracks that would appear even within weeks of Visual Inspection and cause a catastropic failure of the tank. These failures resulted in destruction property, loss of limbs and in at least one case a death. Value of pre 1990 non-catalia tank is about $15 (check local AL scrap prices) for the scrape metal and then my local recycling centes require you to cut the tank in half before the local recycler will take it.

For more about the issue of exploding (rare occurance) tanks read:
http://www.scubabomb.freeservers.com/
http://www.scubabomb.freeservers.com/Scubadag.htm
http://www2.tbo.com/news/breaking-n...man-dies-after-scuba-tank-explodes-ar-256967/

Bottom line, I am culling these tanks from my fleet. Not because of any issue other than too hard to get them filled.

 

[insane04]

thanks . that was what i was looking for

---------- Post Merged at 11:14 PM ---------- Previous Post was at 12:44 PM ----------

well ended up with 5 good AL80s born on date 02 1997

 

[Culcuhain]

Any tank can get a hydro test. But the issue is the AL Alloy used. See this link for infor about the issue: List of Scuba Tanks Made From 6351-T6 Alloy

Many dive shops (for example here in Los Angeles that is most of the dive shops) refuse to fill any pre 1990 AL tank regardless of who made it or the alloy used. Those that will fill them often require you have an eddy-current test done with the annual Visual Inspection which of course cost more money. I don't blame them. It is a safety issue for them and an chance to sell more tanks.

Bottom line, if they are pre 1990, unless you have identified seveal shops in the area (just in case the only one in town that would fill goes out of business), they are worth about scrape metal price ($15 the last time I scraped one).

The issue is not age it is the Alloy they are made of. If they are pre-1990 Luxfer, Walter-Kiddie, or any other brand but Catalina, they are of the alloy that had issues with exploding (mostly in Florida where "cave fills" of +10% were supposedly common.). The theroy is the repeated heating of the metal in these plus fills allegedly changed the composition of the alloy. This is turned resulted in spontainous cracks that would appear even within weeks of Visual Inspection and cause a catastropic failure of the tank. These failures resulted in destruction property, loss of limbs and in at least one case a death. Value of pre 1990 non-catalia tank is about $15 (check local AL scrap prices) for the scrape metal and then my local recycling centes require you to cut the tank in half before the local recycler will take it.

For more about the issue of exploding (rare occurance) tanks read:
The Latest Victim of 6351-T6 Scuba Tanks
Scuba Tank Explodes!
St. Pete veteran killed by exploding scuba tank | TBO.com

Bottom line, I am culling these tanks from my fleet. Not because of any issue other than too hard to get them filled.

Please get your facts straight about the age of the tanks. AL tanks made prior to the dates below are still good and still in use. They require additional testing, but are still usable tanks never-the-less.
http://www.scubaboard.com/forums/ta...66-my-cylinder-made-bad-alloy-aka-al6351.html

All Walter Kidde DOT-3AL cylinders, of which production ceased in
January 1990, are made of alloy 6351-T6. Cliff Impact DOT-3AL cylinders
were made from alloy 6351-T6 before July 1990, at which time Cliff
Impact changed to alloy 6061-T6. Catalina Cylinders did not produce any
DOT-3AL cylinders from alloy 6351-T6; therefore, cylinders manufactured
by Catalina are not subject to this notice.
Until determined otherwise, any DOT-3AL or DOT-E 7235 cylinder
should be assumed to be made of alloy 6351-T6, if it was:
1. Manufactured by Luxfer USA before the applicable date listed in
the chart below;
2. Manufactured by Cliff-Impact before July 1990;
3. Manufactured by any other company in the United States,
excluding Catalina, before February 1990; or
4. Manufactured outside the United States.


Now lets focus on cylinders made by Luxfer as they are the most predominate scuba cylinder made with AL6351:

30 and 63 cu. ft............................. S30, S63 .... mfg date 5-88
40 cu. ft....................................... S40 ........... mfg date 6-88
50 and 92 cu. ft............................. S50, S92 .... mfg date 4-88
72 and 100 cu. ft........................... S72, S100 ... mfg date 8-87
80 cu. ft....................................... S80 ........... mfg date 1-88
80.8 cu. ft.................................... S80.8 ......... mfg date 5-87

 

[DA Aquamaster]

Any tank can get a hydro test. But the issue is the AL Alloy used. See this link for infor about the issue: List of Scuba Tanks Made From 6351-T6 Alloy

Many dive shops (for example here in Los Angeles that is most of the dive shops) refuse to fill any pre 1990 AL tank regardless of who made it or the alloy used. Those that will fill them often require you have an eddy-current test done with the annual Visual Inspection which of course cost more money. I don't blame them. It is a safety issue for them and an chance to sell more tanks.

Bottom line, if they are pre 1990, unless you have identified seveal shops in the area (just in case the only one in town that would fill goes out of business), they are worth about scrape metal price ($15 the last time I scraped one).

The issue is not age it is the Alloy they are made of. If they are pre-1990 Luxfer, Walter-Kiddie, or any other brand but Catalina, they are of the alloy that had issues with exploding (mostly in Florida where "cave fills" of +10% were supposedly common.). The theroy is the repeated heating of the metal in these plus fills allegedly changed the composition of the alloy. This is turned resulted in spontainous cracks that would appear even within weeks of Visual Inspection and cause a catastropic failure of the tank. These failures resulted in destruction property, loss of limbs and in at least one case a death. Value of pre 1990 non-catalia tank is about $15 (check local AL scrap prices) for the scrape metal and then my local recycling centes require you to cut the tank in half before the local recycler will take it.

For more about the issue of exploding (rare occurance) tanks read:
The Latest Victim of 6351-T6 Scuba Tanks
Scuba Tank Explodes!
St. Pete veteran killed by exploding scuba tank | TBO.com

Bottom line, I am culling these tanks from my fleet. Not because of any issue other than too hard to get them filled.

Thanks for perpetuating the general ignorance about 6351-T6 alloy tanks.

The fact is that there are millions of these tanks still in service, yet there has not been a single catastrophic failure of a 6351-T6 alloy tank since eddy current test protocols were implemented over a decade ago.

The DOT has concluded based on testing and field reports that SLC cracks take on average 8 years to propagate from detectability to the point of potential failure. And despite the "theory" you quote above, absolutely no evidence of or substantiated incidents of sudden crack propagation have ever been found. Consequently requires the eddy current/visual plus testing only at the tank's 5 year re-qualification.

The Scuba industry requires annual eddy current inspections however, so for a 6351-T6 alloy tank to fail due to SLC, it would have to be improperly inspected during at least one and possibly 2 (depending on timing) DOT re-qualifications (what divers call hydro tests - which is only a part of the re-qualification process) and it would also have to be improperly inspected 7 or 8 times by dive shops completing annual VIPs and eddy current inspections on the tank.

The only thing I agree with you on is that most shops that refuse to fill 6351-T6 tanks are ignorant of the facts and/or dogmatically maintain a bias from the era when the facts surrounding SLC were less clear. And most of them paint old tanks with the same broad (1990 or older = bad) brush, ignoring the fact that Catalina never made an aluminum tank from anything other than 6061-T6 alloy, and thus no Catalina tank has the SLC cautions that apply to 6351-T6 alloy, or that the Luxfer began switching to 6061-T6 alloy in May 1987, meaning a number of pre-1990 tanks are in fact 6061-T6 and again don't warrant or require the special testing for SLC.

I need to point out here that posts like yours that mis-state the facts only perpetuate the ignorance as well as the "sky is falling" attitudes about 6351-T6 alloy and that contributes to the inability to get them filled in a number of shops.

 

[toliver66]

Hello, sorry to revive an old thread, but I thought it better than starting a new tread on an old beaten dead horse. I'm just getting back into diving after a 12 year SI. I have a Sherwood AL80 I purchased back in 1990, most current hydro/VIS is marked 9 b9/88 00.
Original tank markings:
CTC/DOT-3AL3000P465486LUXFER02^90-S80

Correct me if I'm wrong, but this number is interpreted as:

CTC/DOT - Under Department of Transportation regulations.
3AL - Type of material (aluminium)
3000 - Working Pressure in PSI.
P465486 - Serial number
LUXFER - Manufacturer
2^90 - Born on/first hydro date
S80 - Max air capacity in cubic feet?

Now I have researched this on the internet and by all indications in this thread and other info on the net this is not one of the bad alloy tanks but I haven't been able to find any info to allow me to deduce the alloy this tank is made from. With a current VIS and hydro would this tank be good to go? I'm pretty sure it is but just thought I'd ask the experts for peace of mind.

 

[herman]

You almost have it correct, S80 is the model number, not the capacity of the tank but it is a 80 cf tank.
Luxfer stopped using the 6361 in mid 88 so any tank past that date is not 6361 however many shops use "older than 90" as a guidle line because it's easier. If you read DA's post above, even older tanks are OK to use, they just need a little extra checking at hydro. There is a lot more BS spread around about the problem than there were actual problems. Bottom line is ANY al tank (with a few exceptions that have nothing to do with the 6361 alloy issue) that have passed vis, hydro and if older than 90 has passed a eddie current test it are good to go. This is not to say a dive shop might not be willing to fill them but that is a different matter, store policy as opposed to a leagal issue.

 

[DA Aquamaster]

As Herman indicates the S80 is the model number.

The regular Luxfer 80 is about 26" tall with a 7.25" diameter and is what everyone visualizes when they think "aluminum 80". The Luxfer S80 is a few inches shorter, has an 8" diameter and is a couple pounds less buoyant, being about 2 pounds positive when empty.

It can be confusing as the Catalina S80 is virtually identical to the Luxfer 80 in terms of dimension and buoyancy and is also what people view as an "aluminum 80" , while the Catalina C80 is the same size but has a 3300 psi service pressure and thicker tank walls giving it less internal capacity but the same 80 cu ft capacity and making it neutral when empty rather than being 4 pounds positive like an "aluminum 80".

 

[toliver66]

@--> Herman and DA Aquamaster. Thanks for your responses and clearing up the S80 model designation. I'm relatively new to this forum. I've made a few post but mostly lurking and reading up on changes in scuba diving since I last dove. I've run across quite a few post by you guys and it is obvious you fellas know your stuff. You have earned my respect and I greatly appreciate your help and advise.

I found this site "Scuba Cylinders" after making the above post and it has a section in red about the middle of the page about the Luxfer 6351 aluminum alloy tanks that backs up the info you guys have given here.

Very useful info on the Catalina C80s. I plan to buy a couple more tanks and knowing they are negative when empty they will be Catalina C80s. I should be able to shave a few ponds off my weight belt for a couple of dives anyway.

Thanks again.

---------- Post Merged at 10:46 AM ---------- Previous Post was at 08:30 AM ----------

... I plan to buy a couple more tanks and knowing they are negative when empty they will be Catalina C80s. I should be able to shave a few ponds off my weight belt for a couple of dives anyway.

Then again I probably should just save some bucks and get 2 more S80s and not have to fiddle with my weight belt between dives as all i would be doing is transferring weight from weight-belt to tank and back again. Either way is not going to change my trim as I start a dive negative and end neutral anyway. So, other than SI entertainment there's no point in it.