FS: Aluminum Cylinder - Unknown Size - Pictures and Data Enclosed

I have an aluminum cylinder that has the following data:

Last Hydro: 05-03
Manu Date: 10-81
Manufacturer: Unknown
ID: E6498-3000 .... now 3AL-3000
Estimated Band Size: 7"

Measuring with a tape the cylinder is 22 inches around (wrapping the tank).
From Base to tip of neck (valve not included) is about 20 Inches

Tank has pressure in it.

PICTURES INCLUDED. Make Offer. Highest offer in the next week will get the tank.

PM me your offers.

Pickup in North Florida, High Springs Area

http://techniquest.net/ebay/small-1.jpg

http://techniquest.net/ebay/small-2.jpg

E6498 was the exemption number for tanks made by Luxfer using Alcan 6351-T6 alloy.

So based on that exemption number, it is a Luxfer tank that was later stamped "3AL" when the various aluminum tank exemptions were incorporated into a single "3AL" standard. This particular tank is also marked "USD" indicating it was made for and sold by US Divers. The valve knob looks like the US Divers valve knobs of the era, so I would not be surprised if it has a US Divers valve in it.

The Luxfer 50 was 6.9" in diameter, 19" tall and held 48.4 cu ft, so that's the probable volume of the tank.

Thank you for the info! :)

Happy to help, hopefully you'll find a buyer for it.

If I recall they are about a pound and a half positive when empty (meaning basically neutral with a reg attached) and about 2.5 pounds negative when full (i.e. about 4 pounds negative with a reg attached), so they work ok as a deco bottle.

But they really shine as a tank for kids as the weight is only around 20 pounds and they are short enough to not cause issues for smaller statured people.

But isn't that the bad 6351 alloy?

6351-T6 alloy is susceptible to sustained load cracking and requires an additional Visual Eddy inspection as part of the requalification process that, assuming it passes, will result in an additional "VE" stamp on the tank behind the hydro date.

The scuba industry standard also requires a Visual Plus/visual Eddy inspection at each annual visual inpsection. In practice, in the eleven or so years since visual plus inspections have been implemented at the dive shop level, there have been no catastrophic failures of 6351-T6 scuba tanks in service due to sustained load cracking. Dropping them etc, is a separate issue.

Consequently I'm not sure "bad" alloy is the right term. However a fair number of these tanks have been removed from service during requalification (hydro) testing due to incipent or developing SLCs, so the major risk is that the tank could fail the next requalification or a furture requalification due to an SLC. The other big issue is that many shops won't fill them. Either outcome would be "bad" if you just bought the tank.

Selling the tank with a fresh hydro and visual inspection, or contingent upon successfully passing requalification would probably make most people feel more comfortable buying a 6351-T6 alloy tank.

"Bad alloy" is the term I used because the shops refusing to fill them is a huge problem. I would guess more 6351 tanks have been taken out of service because shops (and individuals) don't want to fill them than for SLC. I do my own fills and recently got rid of my last 6351 tanks. Just not worth the headache or risk.

I understand that you can get $20-$30 for them as scrap metal.

Quote:

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Originally Posted by DA Aquamaster

Selling the tank with a fresh hydro and visual inspection, or contingent upon successfully passing requalification would probably make most people feel more comfortable buying a 6351-T6 alloy tank.

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Either way, whom ever is taking it in for hydro should verify with the shop what their policies are on charging for the tests if the tank fails. I took a pair of 6351 tanks in for hydro (under the impression they were 6061, long story, should have paid more attention, I do know better). Thinking for $30 I would have 2 hydro'd 6061 tanks... one failed VE. VE tests were an extra $15, regardless of passing. So for a total of $45 I have one good 6351 tanks... NOT WORTH IT.

FWIW, the guy VE tests them, then hydros them, then VE tests them again. It passed the first and failed the second. No crack was ever visible but was obvious on the report. He didn't charge me for the hydro.

I am happy to dive/fill/store/handle properly maintained 6351 tanks, but I am no longer willing to deal with the bull **** around filling and testing.

Quote:

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Originally Posted by FW

I understand that you can get $20-$30 for them as scrap metal.

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I have heard it's really around $15 each, unless you have them cut in half first. A 50 would likely be $10-$15 anyways. WK cylinders are actually worth a bit more, because they used a bit more metal.

Yeah, our owner regardless of VE or not, will not fill this tank. Most of the shops in my immediate area are the same way.

All you people talking about 6351 this, 6351 that - can you not see "6498" staring you in the face?

Which is beside the point - sand it down, put a nice coat of paint on it, drill a hole in the bottom for the cord, and make a lamp out of it. It's thirty years old and made of aluminum, for crying out loud.

Quote:

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Originally Posted by Slüdge

All you people talking about 6351 this, 6351 that - can you not see "6498" staring you in the face?

Which is beside the point - sand it down, put a nice coat of paint on it, drill a hole in the bottom for the cord, and make a lamp out of it. It's thirty years old and made of aluminum, for crying out loud.

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Russel, "6498" is the exemption number for the engineering specifications under which it was made. 6498 refers to the exemption given to Luxfer to make the tanks to said engineering specification from, in this case, 6351 alloy and a T6 heat treatment process.

It's confusing, but that's the federal government for you. I do agree howeveer that life would be simpler if the alloy and heat treatment used in various early AL tanks had been stamped on the tank.

Quote:

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Originally Posted by Greenwood_60

Either way, whom ever is taking it in for hydro should verify with the shop what their policies are on charging for the tests if the tank fails. I took a pair of 6351 tanks in for hydro (under the impression they were 6061, long story, should have paid more attention, I do know better). Thinking for $30 I would have 2 hydro'd 6061 tanks... one failed VE. VE tests were an extra $15, regardless of passing. So for a total of $45 I have one good 6351 tanks... NOT WORTH IT.

FWIW, the guy VE tests them, then hydros them, then VE tests them again. It passed the first and failed the second. No crack was ever visible but was obvious on the report. He didn't charge me for the hydro.

I am happy to dive/fill/store/handle properly maintained 6351 tanks, but I am no longer willing to deal with the bull **** around filling and testing.



I have heard it's really around $15 each, unless you have them cut in half first. A 50 would likely be $10-$15 anyways. WK cylinders are actually worth a bit more, because they used a bit more metal.

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I am impressed with the before and after visual eddy test. For reasons related to not wasting time and expense hydro testing tanks that would fail a visual inspection anyway, visual testing precedes hydro testing in the requalification process. However with aluminum tanks and SLC, I have seen tanks with no detectable cracks undergo hydro testing whihc then caused enough propogation for a crack to be detected. In that case, particularly with Aluminum tansk that will not be condemned on a visual inspection for rust, as is often the case for a steel tank, it makes more sense for the visual eddy to be done after they hydro test. This tester is obviously meeting the regulatory requirement to cover his ass, but is then also doing the test post hydro to ensure maximum effectiveness of the Visual Eddy test in catching incipent SLCs.

However, it's also redundant as the dive shop putting a VIP sticker on the tank after it comes back from hydro will also do their own visual plus/visual eddy inspection.

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Some recyclers will not accept tanks unless they are cut in half. My understanding is that the reasons often cited are to 1) ensure there are no contaminants or chemical waste in the tank and/or 2) because any air trapped in the tank when it is dropped in a smelter could rapidly expand and blow molten aluminum all over the place.

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Personally I don't have any issues filling or using a properly inspected 6351-T6 tank, but again that includes a visual plus/visual eddy inspection done after the hydro test and repeated annually. In that regard, if this tank had a current requalification and in addition the scuba industry standard Visual Plus/Visual Eddy inspection, I'd have no issue with buying it.

Quote:

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Originally Posted by DA Aquamaster

6498 refers to the exemption given to Luxfer to make the tanks to said engineering specification from, in this case, 6351 alloy and a T6 heat treatment process.

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I agree, it's confusing. But when I was trained on the Visual Plus machine (from AIT), I was told 6498s didn't have the SLC problems - which is not enough to convince me to fill a thirty-year-old aluminum cylinder that's sitting crotch-level.

Quote:

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Originally Posted by Slüdge

I agree, it's confusing. But when I was trained on the Visual Plus machine (from AIT), I was told 6498s didn't have the SLC problems - which is not enough to convince me to fill a thirty-year-old aluminum cylinder that's sitting crotch-level.

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Someone told you wrong as that exemption used 6351-T6 and belonged to Luxfer who used 6351-T6 at that time.

The only company that made aluminum scuba tanks in that era that did not use 6351-T6 alloy was Catalina - they have always used 6061-T6 aluminum.

SOLD - As scrap. Thanks everyone.