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

[Sludge]

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.

[DA Aquamaster]

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.

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.

[DA Aquamaster]

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.

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.

[Sludge]

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.

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.

[DA Aquamaster]

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.

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.

[FloridaCaveDiver]

SOLD - As scrap. Thanks everyone.