My two cents on used tanks

[jrwands]

Let me begin by saying that I don't wish this to be malicious but at the same time I hope others may learn from this and avoid having a similar experience. I was looking for a couple of scuba tanks and I was trying to pick some up cheap because I was concerned that they might not get much use. I do most of my diving with a group of guys and there are usually plenty of tanks to go around, but some family members said they wanted to get back in the water and I would not have access to those tanks when diving with them. I placed a wanted add on craigslist, and found someone with tanks for sale. I purchased 4 tanks from (Ted L. of New Brunswick). When I purchased the tanks he told me he would refund my money for any that failed hydro testing, which all 4 needed. One of the tanks failed a visual plus inspection, which was required for all four tanks as they were all made of the older 6351 aluminum alloy. I have been diving since 1990 and have never purchased used tanks before so I had not come across this issue previously and did not read up on it until after I had paid for the tanks and testing. Whether he was aware of the issues with these older tanks or not when he sold them to me I cannot say, but his response since suggests to me that he may have been fully aware. My guess at this point is that I was completely duped. When I notified him that one had failed visual inspection he said and I quote "I'll chalk it up to your being rather new to the sport, but if a tank flunks a "visual" one simply has it cleaned! Furthermore the whole "visual inspection" thing is simply a concept manufactured by the dive industry; visuals are not required via legal code unlike hydros which come under the DOT. Lastly, as you may recall, are arrangement was specifically about tanks failing hydro. Nothing was said about visual inspections." In response to this smug answer, I am not new to diving and the visual plus test is required by the DOT on these tanks. Now I am out what I paid for the tank and the cost of the visual plus inspection. He had a lot more gear he wanted to get rid of as well so this may not be last case where this will happen. If you choose to do business with Provo Ted at hotmail, be warned that he is not a man of his word and you will likely have no recourse if there are any issues with any items you may purchase from him. As far as used tanks are concerned, having looked into it further I would not purchase anything older than a few years or I would avoid used tanks all together in the future. Absolutely avoid anything with an original hydro date prior to 1990 to be safe.

 

[vshearer]

Your last comment about avoiding any ALUMINUM tanks older than 1990 is the key. And yes, I have run into a couple of people trying to pass off older tanks who I believe were well aware of the issues (Not here on SB though)

 

[deepstops]

Only buy Catalina cylinders if they're older than 1990. Any dive shop that makes "blanket statements" about all makes of pre-1990 tanks isn't the one where I'll be spending my money.

 

[spectrum]

jrwands,

The seller may have stood behind semantics but you didn't do your homework when you bought those cylinders. At best they are expensive to certify with the additional eddy current test and it is unpredictable who will be willing to fill them even fully stickered. If you cut an appropriate deal even with your losses you should have good value in the 3 cylinders that passed.

The whole aluminum thing has turned into a whipping boy. As you mention the 6351 cylinders most commonly from Luxfer are prone to sustained load cracking but per Luxfer can be safely used if checked with an eddy current tester (visual plus) at VIP. Prior to this extra step there were a number of failures on just a year (or 2?) ago in Rhode Island. Anyhow many have decided they don't even want to touch these things. To celebrate the 20th anniversary of the demise of 6351 we are starting to see shops blackball cylinders when they hit 20 years of age regardless of alloy or manufacturer. This is rooted in ignorance or underhanded cylinder marketing but as you said it's unregulated and it's they who own the compressors for most of us.

Sorry you got short sheeted but we always have to assume some risk when bottom feeding.

Pete

 

[spectrum]

Only buy Catalina cylinders if they're older than 1990. Any dive shop that makes "blanket statements" about all makes of pre-1990 tanks isn't the one where I'll be spending my money.

Unfortunately in some areas compressors are far and few and divers can't always be so independent.

 

[Jim Lapenta]

It's also why I only buy steel tanks. I have one al80 and I bought it new two years ago. I know it'll be alright for a good long time. Especially sinc I fill my own and it's just a backup anyway and will eventually get relegated to use as a stage.

 

[divebostonforcharity]

I've bought used tank a couple of times but I will only buy them if they don't need a hydro for at least a year and if the seller has them partially full. Before handing over any money I hook them up to an old reg to make sure nothing is wrong with the valve. Then I empty them, take off the valve, and shine a flashlight inside to make sure there are no obvious rust spots. Although this isn't foolproof, I have never had one fail a vis. I do usually have to pay more for used tanks in good condition though.

 

[DA Aquamaster]

The information below is extracted from DOT Advisory 94-7 regarding what tanks are made from 6351-T6 alloy and are subject to eddy current inspection:

The following are the Luxfer tanks made from 6351-T6 alloy and the dates they switched to 6351-T6 allloy.

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


In addition:

1. All Walter Kidde DOT-3AL cylinders, of which production ceased in
January 1990, are made of alloy 6351-T6.

2. Cliff Impact DOT-3AL cylinders were made from alloy 6351-T6 before July 1990, at which time Cliff Impact changed to alloy 6061-T6.

3. Catalina Cylinders did not produce any DOT-3AL cylinders from alloy 6351-T6; therefore, cylinders manufactured by Catalina are not subject to this notice.

4. Until determined otherwise, any DOT-3AL or DOT-E 7235 cylinder
should be assumed to be made of alloy 6351-T6, if it was:
a. Manufactured by Luxfer USA before the applicable date listed in
the chart above;
b. Manufactured by Cliff-Impact before July 1990;
c. Manufactured by any other company in the United States,
excluding Catalina, before February 1990; or
d. Manufactured outside the United States.

5. Aluminum alloy 6351-T6 has been used in the
manufacture of the following DOT high pressure cylinders:
Cylinders (seamless aluminum) marked ``DOT 3AL'', including
those marked with ``DOT 3AL'' above or near one of the following
exemption or special permit numbers:

6498
7042
8107
8364
8422

---------

There has not been an SLC related failure of a 6351-T6 tank in service since the adoption of Eddy Current inspections that began in 2000. It is not unusual for 6351-T6 tanks to develop cracks, but they propogate so slowly that they will be detected long before they progress to the point of posing a risk of tank explosion. That was the reason the DOT finally adopted the requirement that the eddy current/visual plus inspection be part of the rewualification process. The dive industry still requires it as part of the annual VIP process. So in effect, a tank with a crack would have to have that cracked missed at a hydro test and up to 5 annual inspections before it would have enough time to pose a hazard. Thats pretty redundant and as a result properly inspected scuba tanks made from 6351-T6 alloy do not pose any additional fill risk.

------------

As for the seller stating he was only guarenteeing the tanks passed hydro, the eddy curent/visual plus inspection is a required part of the hydro test/requalification process for any cylinder made of 6351-T6 alloy, so if it fails the visual due to a neck crack it cannot be requalified and fails the common definition of "hydro" test.

 

[Scared Silly]

Here is the advisory that DA notes:

http://hazmat.dot.gov/pubs/reports/cylinder/3al_advisory.pdf


Here are the rules for 6351 Cylinders:

http://a257.g.akamaitech.net/7/257/2422/01jan20061800/edocket.access.gpo.gov/2006/pdf/E6-14255.pdf


I would present the later to the OP's sellers and note that technically the cylinder failed the hydro as the eddy current test is part of the hydro.

As for those selling and those buying cylinders - unfortunately both can be naive about the 6351 cylinders.

 

[jrwands]

Thanks to you all for your input. I was really restating numerous things that have already been said elsewhere. I also wanted caution others about doing business with this individual since he had a lot of other gear that he was looking to get rid of.